hybridfree/eevblog-posts huggingface dataset:
Serious ringing on U_GS in BLDC MOSFET bridge - Page 1
Forum section: electronics / projects

author: Jake the Snake
author_rank: Newbie
timestamp: September 26, 2019, 06:01:30 pm
content: Hi Everyone!I am currently designing a motor inverter for a PMSM Motor and have some trouble with ringing on U_GS on the low-side MOSFETs when they turn off.The specs for the inverter are as follows:- ~29V Input from Lithium Battery- Standard three phase design with three phase low-side current sensing- Max. Phase current ist around 60A- Full 4Q-Operation (forward and reverse with regenerative braking and accelerating)- Incremental Encoder for rotor position sensing- 28kHz switching frequencyI am using the following setup:- STM32F415 with ST CubeMX Motor control Library- TI DRV8323RS Smart Gate Driver and current sense amplifier- 5mOhm Shunts below each low-side FET- Nexperia BUK9Y7R2-60E MOSFET (60V, 7.2mOhm, 12nC, LogicLevel)Please see the attached schematic and the layout for more details. To increase the cross-section in the positive supply rail (left side of layout) we have soldered some copper that reaches out directly to the MOSFETS. I know that the layout might not be perfect but we have some constraints regarding component placement. Phase terminals HAVE to be on the very left and mosfets should be on the right.Exact problem description:We encounter a lot of ringing on U_GS when we turn off the low side MOSFETs. I dont have a picture handy (no USB drive in lab to copy from scope), but the overshoot is around 100% of the supply voltage at 20A phase current. So U_GS spikes are around 60V at 30V Supply. As soon as I increase the current to lets say 30A, we blow one of the FETs (kind of expected).The measurement was done with a Rigol DS1054Z with a probe and the clip on spring directly over drain and source. So no large ground loop or anything that could have influenced the measurement?I have some questions regarding possible solutions...- Decreasing gate drive current should help in theory (same dI, larger dt), but did not really help. I tried changing from 2A to 500mA. Will check with 100mA again tomorrow.- Ceramic Caps from Supply+ to GND near the FETs should also help, according to most people. We already have plenty of caps there (5 * 4.7µF, 50V, X7R per phase) and I struggle to understand the theory why they should help?- Changing dead time should have no effect. Right?- Any Ideas to change the layout to decrease inductance?- Any obvious mistakes I might have done?Thanks and best regards,Jake

author: Jake the Snake
author_rank: Newbie
timestamp: September 26, 2019, 06:57:41 pm
content: Hi Blueskull,thanks for your reply!I am not sure, if I understand you correctly. The gates are not driven by the battery rail directly! This would turn them on all the time.I am generating 6 PWM Signals to the TI DRV8323 Gate driver. The DRV8323 has an integrated charge pump and takes care of the high-side MOSFETs.Gate signals should be alright, as the bridge runs great on lower currents.Thanks,Jake
Server VRM Module - Page 1
Forum section: electronics / projects

author: Tinkerlad
author_rank: Newbie
timestamp: July 08, 2016, 01:57:14 pm
content: Hi all,I recently acquired a heap of 290560-001 VRM modules from a set of old servers. I know that they all take 12v DC input, but I cannot find a pinout for them anywhere.Anyone had any experience with these?Thanks

author: David Hess
author_rank: Super Contributor
timestamp: July 09, 2016, 04:15:51 am
content: Do they have thick collet pins on one side?I think Intel had standards for the replaceable VRM modules back in the Pentium II and Pentium III generation. The Intel ones are incredibly reliable in my experience.
Service Manual for Kindle Keyboard - Page 1
Forum section: electronics / projects

author: MikeNye
author_rank: Contributor
timestamp: May 22, 2013, 11:12:10 am
content: Hi everyone,I'm troubleshooting a friend's Kindle Keyboard, and I'm having some issues... I've been digging around for a service manual however haven't had much luck. Can anyone help me out?Thanks all.Kind regards,Mike Nye

author: amyk
author_rank: Super Contributor
timestamp: May 22, 2013, 11:31:27 am
content: You'd be lucky to find even a leaked schematic for this sort of device... reverse-engineering skills are your friend. What sort of issues are you having exactly?

author: MikeNye
author_rank: Contributor
timestamp: May 24, 2013, 03:34:16 pm
content: Just won't turn on. Sliding power switch doesn't give green LED. I replaced the battery as the old pack was dead. It now charges (and I get the amber LED when charging), but still the same issue. I was hoping to find out what the test points are so I had a better idea of where to look.Thanks for responding.
Service Manual Template in Word or Open Office? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: September 30, 2018, 11:25:48 am
content: Hi!Just a quickie one!Can anyone point me in the direction of a free, high–quality template of a Service/Maintainence Manual, or an editable ready–written Service Manual in Word, Open Office I can re–write to suit my needs, or similar please?I'm looking for something with an attractive illustrated cover, a ready written contents page, several written sections in the middle for theory of operation, adjustments & setting up, flowcharts for faultfinding, tabular parts lists and pages for circuit–diagrams at the back.Chris Williams
Servicing first gen Motorola 8000x analouge mobile phones - Page 1
Forum section: electronics / projects

author: chickenlipss66
author_rank: Newbie
timestamp: March 17, 2013, 10:20:54 am
content: Hi, i collect early analouge Motorola phones (8000x - 1983-1985). I have opened a few handsets to swap boards, but i am now having probelms re starting a handset. I have the orginal moto service manauls, but no one i speak to has any experience working on these handsets. Has anyone out there ever worked on moto 8000x ?

author: qno
author_rank: Frequent Contributor
timestamp: March 17, 2013, 08:17:14 pm
content: Is the network it has to connect to still in service?As far as I can remember these phones worked in the 400 MHz range.The supporting network has been dismantled a few years after the GSM phones arrived.Old analog phone base stations are used as a relay station for in the HAM radio scene.Maybe try your luck there?

author: justcarkits2
author_rank: Newbie
timestamp: July 21, 2013, 04:38:46 pm
content: Hi, yes have worked on the 8000X, 8000S, 8500X, 8800X, 9800X and used to work at a Motorola service centre.The 8000S & X were my speciality and was the first person outside of Motorola UK allowed to repair them.The UK TACS model 8000X was launched from mid/late '85 onwards and operated in the 900Mhz band with a 45Mhz offset

author: Spectreman
author_rank: Newbie
timestamp: August 29, 2013, 12:57:45 am
content: Hi Chickenlipps.I collect Motorola analogue mobile phones too.I only have two Dynatac brick phones so far, 8000s & an America Series 865.The 8000s is a non worker, internals are damaged from battery pack leakage (bit of a problem with these old phones if the battpack is left on the phone). The 865 works fine.I found the 8000s quite hard to take apart. I do not have any service manuals at all for these phones.Any chance I could get a copy of one of your Dynatac service manuals ?Cheers, Chris.
Servo angle - Page 1
Forum section: electronics / projects

author: abdulsamaddabu
author_rank: Contributor
timestamp: September 06, 2017, 08:43:45 pm
content: hey i was trying to control the servo using joystick(potentiometer).i am but stuck at a problemwhen joystick is at center servo is at 90° when i move the joystick to left, servo sets at 0° and when i release the joystick it came back to its 90° but when i move the joystick to right, the server does sets to 180° but does not come back to 90° on release the joystick, it sets to a little more than 90° like 100°what could be the problem ?#include <Servo.h>Servo servo;int sp ;int js_x;void setup(){servo.attach(3);}void loop(){sp= map(js_x ,0 ,1023, 0, 180);servo.write(sp);}

author: janoc
author_rank: Super Contributor
timestamp: September 06, 2017, 10:04:19 pm
content: Are you sure that your joystick actually returns the same value? Some crappy ones will not return the same value when centered, having a large "dead zone".Also the servo could be junk - common cheap RC servos are not precision devices, the feedback is simply a potentiometer inside the casing and if the gears have backlash it may not return to exactly the same position. Basically a mechanical hysteresis.BTW, the code above is unlikely what you are using because it doesn't read the joystick anywhere ...

author: langwadt
author_rank: Super Contributor
timestamp: September 06, 2017, 10:30:25 pm
content: Quote from: janoc on September 06, 2017, 10:04:19 pmThe RC servos I've had apart all had the pot connected to the output shaft so backlash in the gears wouldn't affect the position
SERVO CONTROL FOR MOTORCYCLE CLUTCH - please help - Page 1
Forum section: electronics / projects

author: Ronsta
author_rank: Newbie
timestamp: May 24, 2022, 12:30:49 am
content: Hi there, I'm after some advice/parts..I have a friend who lost his arm in a motorcycle accident but still loves to ride so I've been modifying his bikes for quite a few years now.Up until now they have been semi automatic gearbox bikes like the Honda CRF1000 but now he has a new Yamaha MT09 with a regular clutch.We have tried several ideas with hydraulics but the lever (thumb) is always too heavy.Anyway, I've decided on a 60kg RC servo which I've hooked up through my RC car and it looks like it's going to work fine to actuate the clutch however I want to eliminate the radio control side of things and have it hard wired with the servo, the bikes battery, a servo controller and a potentiometer mounted on the handlebar for his thumb.I've found several 555 circuit diagrams on the internet, servo testers and also arduino plans but I want to steer clear of complexity and the 555 or servo tester route only seems to work from 5v..Here's what I'm working with:12v motorcycle battery.8.4v 60kg digital servo.Any advice would be greatly appreciatedRon Cooper
Servo Controller Board Critiques - Page 1
Forum section: electronics / projects

author: anvoice
author_rank: Frequent Contributor
timestamp: August 12, 2018, 11:25:17 pm
content: I've designed a modest BLDC servo controller that I'd like to put forth for your critique. I by no means ask you to evaluate the whole thing, but I welcome all criticisms, suggestions and corrections since I'd like to minimize the number of prototype boards I have to make. The PDF of the schematic and Kicad files are attached.The design is based around the ATSAMD21 MCU with a DRV8323SRTAR BLDC driver. Using 3 dual N-channel mosfets and a AS5048A magnetic encoder for position sensing. The encoder dictates the layout of the PCB since it must be right under the motor center, hence the awkward-looking board. I tried to make the routing as neat as possible, but some layer-hopping was inevitable.One of the unknowns is the motor current draw, estimated to be about 30A: the Chinese vendor I got the motors from ignored my email asking for that parameter, so I was thinking of measuring that myself using the first boards I make (since I have current sense resistors), soft-starting the motors so as not to burn out the board, and then adjusting the design accordingly if necessary.Also, I'd be glad to hear suggestions as to which board manufacturer would be good to use for this project. I've gone with OSH Park before but I heard that their copper isn't as thick as it could be, and I'll have high currents going through the trace going to the current sense resistors and the motor to mosfet connections. Thanks in advance.
Servo Controller Board with 2 Power Supplies - Page 1
Forum section: electronics / projects

author: butters
author_rank: Newbie
timestamp: August 14, 2010, 11:26:51 pm
content: Hi guys, I've been working on this board for awhile now and it's basically designed to control a quad 2-input multiplexer (74AC157MTC) to switch between an external set of servo control signals (coming from another board) and servo control from the on-board ATMega1281. The board has to be reduntantly powered (it's essentially a failsafe system) with its own little battery (I'm gonna use a single cell LiPo), but I am at odds with how to deal with the servo power lines. The servos are powered by their own high-capacity 5V NiMH battery and will pull quite a few amps at times.I initially thought that I would be able to power the servos seperately from the board with their own battery as long as I keep a common ground between the two voltage sources, however some preliminary testing is suggesting that this won't work. Is having the servo control signal driven by a different voltage source from the servo power source going to be an issue when I try to control the servos with the on-board microcontroller?

author: RayJones
author_rank: Frequent Contributor
timestamp: August 15, 2010, 12:22:43 am
content: By the "servo" I presume you mean the model type with a nominal 1.5ms PWM control?There are many and varied servo systems in the worldIf so, obtaining a PWM signal from another system will not cause an issue, so long as your grounds are commoned.You could use an opto coupler if you really desire isolation...
servo motor control problem - Page 1
Forum section: electronics / projects

author: amangg
author_rank: Newbie
timestamp: February 01, 2018, 09:56:12 am
content: hello everyone,I am working on the objective of using IR sensor to control the movement of a servo motor on an arduino unoThe motor responds to the value but not every time.It moves on random signals but most of the time does not respond. It continuously produces knocking/clicking sounds without any movement of the gear.The servo independently has been tested and works totally fine.Any ideas why i am facing this problem ? I am also thinking of timing the signals for better monitoring . How can I do that?Here are the components :1. IR sensor - Sharp IR sensorhttp://www.sharp-world.com/products/device/lineup/data/pdf/datasheet/gp2y0a21yk_e.pdf2. servo motor - tower pro 996Rhere is the code :-Code:#include<Servo.h>Servo servo1;int analogPin = 3 ;int dist = 0 ;int i =0 ;void setup() {Serial.begin(9600);servo1.attach(9);// digitalWrite(A3, INPUT_PULLUP);}void loop() {dist = analogRead(analogPin);dist = map (dist,0,1023,0,20);Serial.println(dist);{for (i=0;i<20;i++){if (dist==i)servo1.write(dist*10);}}delay(2000);}

author: paulca
author_rank: Super Contributor
timestamp: February 01, 2018, 02:55:47 pm
content: Emm...Serial.println(dist);servo1.write(dist*10);delay(2000);Try that.Also check in the servo library that it is not sending a high frequency. PWM frequency 50-100Hz is more than enough.Do you have an oscilloscope? If you do, probe the signal pin on the servo.You might also need to calibrate the servo to find it's max and min positions.Simplify your code back and move the servo through 0-255 in a loop with a 100ms delayfor( int pos=0; pos<255; pos++) {servo.write(pos);delay(100);}You will find it won't move immediately but will buzz and it will stop before 255 at the other end and buzz.

author: phil from seattle
author_rank: Super Contributor
timestamp: February 02, 2018, 12:58:44 am
content: Are you sure you have the servo pins right? Signal and Vdd being switched could be a cause.The library has a lot of users so I suspect it's not the problem. The PWM frequency will be 50 hz and the duty cycle is 10 to 20%.I agree with paulca that you should write a little test program. You only need to go from 0 to 180 degrees. You might want to make the delay a little smaller - I'd use 10. 100 will take 5 minutes to run through 180 degrees. Though, I'd first do a servo1.write(0); followed by a 2 second delay to allow it to return to the 0 position and then step from 0 to 180.

author: hussamaldean
author_rank: Unknown
timestamp: February 02, 2018, 06:13:52 am
content: could you please elaborate ?
SesCom  SIP modules - Page 1
Forum section: electronics / projects

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 06, 2024, 05:48:27 pm
content: Does anyone have any info about the "SIP" modules from SesCom?There were around 20 different postage-stamp-size modules: SIP-1, SIP-2, etc.....They were (mostly/all) audio-related.SesCom is no longer in the business of selling these modules and other "maker"-type products.I would like to revive these modules and make them available open-source on the popular PCB vendors.

author: GLouie
author_rank: Regular Contributor
timestamp: November 06, 2024, 09:52:17 pm
content: Don't know much about them, and can't find my catalogs from that period, but I have a Sescom RS-SB dual balanced-unbalance box that has a SIP-1 in it. I think it says copyright 1991.I was given the RS-SB and was looking for info on it some years ago. I recall seeing an old catalog with some modules listed, but I think the modules were only around for a short time.
Set of four TL866II-Plus programmer stopped working - Page 1
Forum section: electronics / projects

author: Circlotron
author_rank: Super Contributor
timestamp: February 17, 2024, 10:44:43 am
content: I have a set of four TL866II-Plus programmers running off my Linux Mint pc and for several years everything has been working okay. Just tonight they have all stopped working. The programming software was bugging me to update it so I did but no improvement. It is now version 12.66The individual programmers are TL866II-Plus Ver: 04.02.132The PC recognises them as being connected. Used USBview.Code:Xingong XGecu USB Prog.. DeviceManufacturer: Xingong Electronicg Co..Speed: 12Mb/s (full)Bus: 1Address: 57USB Version: 2.00Device Class: 00(>ifc )Device Subclass: 00Device Protocol: 00Maximum Default Endpoint Size: 8Number of Configurations: 1Vendor Id: a466Product Id: 0a53Revision Number: 0.00Config Number: 1Number of Interfaces: 1Attributes: c0MaxPower Needed: 100mAInterface Number: 0Name: usbfsAlternate Number: 0Class: ff(vend.)Sub Class: ffProtocol: ffNumber of Endpoints: 6Endpoint Address: 01Direction: outAttribute: 2Type: BulkMax Packet Size: 64Interval: 0msEndpoint Address: 81Direction: inAttribute: 2Type: BulkMax Packet Size: 64Interval: 0msEndpoint Address: 02Direction: outAttribute: 2Type: BulkMax Packet Size: 64Interval: 0msEndpoint Address: 82Direction: inAttribute: 2Type: BulkMax Packet Size: 64Interval: 0msEndpoint Address: 03Direction: outAttribute: 2Type: BulkMax Packet Size: 64Interval: 0msEndpoint Address: 83Direction: inAttribute: 2Type: BulkMax Packet Size: 64Interval: 0msI remember some time ago I had to reflash the programmers after upgrading the software but I can't remember how I did it.Actually if I disconnect and reconnect the programmers multiple times the software eventually sees them, but if I run Tools / System Self check it comes up with VPP Testing... Write device error.What should I do now?Edit -> They *seem* to be running okay in Win7 in VirtualBox.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: February 17, 2024, 10:57:44 am
content: If you are trying all of them from one PC then I think the PC is the more likely suspect? Try another PC?

author: jonpaul
author_rank: Super Contributor
timestamp: February 17, 2024, 11:29:01 am
content: ChiCom form XGeu has history of "bricking" working products with a FW "upgrade"Try to flash back one FW rev earlier.j

author: pienari
author_rank: Regular Contributor
timestamp: February 17, 2024, 11:59:00 am
content: Windows driver issue.

author: Circlotron
author_rank: Super Contributor
timestamp: February 17, 2024, 12:19:28 pm
content: As above, they work okay on Win7 in VirtualBox on the same PC, so the issue lies entirely with Linux.Update -> tried it once again on Linux after doing 40 eproms on win7 and the darn things work just fine now...Previously when I ran I run Tools / System Self check it would come up with "VPP Testing... Write device error" but now it checks out okay.
setting pull-down bias on userspace GPIO in embedded linux - Page 1
Forum section: electronics / projects

author: davegravy
author_rank: Regular Contributor
timestamp: October 26, 2024, 11:17:55 pm
content: It seems the pins onthis SBCdefault to pull-up, which I need to change. I spent a while modifying the device tree but while it's easy to configure pins that you're binding to a device with a driver (like gpio-keys) it seems impossible to do it for GPIO that you want to use in userspace. I hope I'm wrong and someone knows of a way.I tried to set bias using gpiod, which involved needing to compile the latest version in order for gpioset to support the --bias parameter. It doesn't throw an error but it also doesn't work. I read some rather negative things about libgpiod in my quest for an answer.The only success I've had is using busybox devmem to directly write to the memory address that controls the pin config. I feel like direct memory manipulation like this is kind of dangerous but as it stands running this on startup is the only option I see.Please let me know if there's a better way you know about.
Setting the bounds for integration LTSpice - Page 1
Forum section: electronics / projects

author: Etesla
author_rank: Regular Contributor
timestamp: October 29, 2019, 02:13:15 pm
content: Hi allIs it possible to set the bounds for the LTSpice idt() function? I am trying to use the average value of a waveform. The average I am talking about is the moving average calculated from the most recent 5 seconds of the waveform. It would be easy if I could integrate the waveform from (time-5) to (time), but I don't see an easy way to do it. Any suggestions?

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 29, 2019, 02:34:00 pm
content: The idt() function integrates from the beginning of the simulation, although there are means of resetting the integration (see the online help, 'a' parameter). There's also an alternate way of resetting it with the idtmod() function.For a moving average, neither would be very helpful. (You could use them to compute averages in "chunks", but that's not what you asked for.)I think you could use the following "trick" though (assuming 'x' here is the expression in question):Code:idt(x - delay(x, 5))The delay() function yields a delayed version of its parameter. The above would just be equivalent to subtracting the integral of the signal 'x' delayed by 5s from the integral of the signal 'x', which should give you what you want.Don't hesitate to report back if it works fine or if you need further help.

author: iMo
author_rank: Super Contributor
timestamp: October 29, 2019, 05:41:38 pm
content: Not sure this is what you are looking for, but you may do average from time A to B in the waveform viewer (ctrl leftclick on the waveform's label on top).
Setting up KiCad gerbers - Page 1
Forum section: electronics / projects

author: Dajgoro
author_rank: Frequent Contributor
timestamp: January 13, 2015, 11:20:38 am
content: Hi.I want to get into proper pcb design, and have pcb-s manufactured not only homebrew.I used to use eagle, but being limited in the free version I gave up since I often need more area.Now I decided to give a try to KiCad, but now I have another problem.Pcb manufacturers tend to give design rule files for eagle, and me being still a newbie when it come to that i have no idea how those rules actually work with pcb editors.So how do I set up KiCad so that I can generate gerbers that would work for something like Electrow or imall?http://www.elecrow.com/5pcs-2-layer-pcb-p-1174.htmlhttp://imall.iteadstudio.com/im120418001.html

author: kingofkya
author_rank: Regular Contributor
timestamp: January 14, 2015, 12:37:01 am
content: Elecrow is very good about telling you were you messed up.But basically you want to setup a reasonable clearances .20 mm minimum trace and clearance will put you near the 8mils range they specify. That is what they recommend on elecrow and before you produce the gerbers you want to hit the DRC button to make sure you didn't miss something.If i recall correctly kicads defualt setup is .251mm so it shoudl be good out of the box.Also the silkscreen text is always smaller than you think it is make it larger as you can:)
Setting up TFT LCD using STM32, FT810 and Eve Screen designer  - Page 1
Forum section: electronics / projects

author: ALPR76
author_rank: Newbie
timestamp: January 13, 2024, 06:11:56 am
content: Hello to allI am planning to setup a TFT LCD with FT810 driver and Eve Screen Designer software output with STM32 or ESP32 microcontroller.I got help from the help file in the link below, but in the end, I don't know what functions I should call in the Main file and in the While() section to display the output on the LCD.I would be grateful if you could help mefile:///D:/TFT-LCD-HT810/ESD-4.10-Exported-Project-Porting-Guide-for-STM32L4-Discovery-Board-and-FreeRTOS.pdf

author: DavidAlfa
author_rank: Super Contributor
timestamp: January 13, 2024, 07:00:27 am
content: https://github.com/RudolphRiedel/FT800-FT813/tree/5.x/examples
Setting VME control registers with a uC? - Page 1
Forum section: electronics / projects

author: macona
author_rank: Regular Contributor
timestamp: October 22, 2020, 09:32:53 am
content: I have a Zygo ZMI-1000A VME board I am going to be running in standalone mode. Manual :https://drive.google.com/file/d/1BdC5PO9Ez9nzBIuFvZiN9O6MMSnOlnyf/view?usp=sharingBy default at powerup the board starts in a mode where it dumps 32bit positional data on the P2 bus where I am planning on reading out with a NI 96 channel USB digital IO unit.But there are a few other modes that would be nice to access but to do that I have to write to a couple control registers on the VME side of things. So I was thinking of taking a teensy and just have it write those registers at power on.I have never messed with VME before, so this is what I think I need to do, I am hoping someone will be able to sanity check this. I have been reading various VME tutorials and I came up with this.The plan is:Set the address switches to 0000Set the Address Modifers bits AM5-AM0 to 101101 ($2D) Probably just hard wire this. This puts the board in 16 bit addressing modeSet LWORD* highSet address bits A15-A1 all low (Offset $00)Pull AS* lowSet data bits D15-D0 0001000000000000 (Turn on user LED on front panel)Pull DS0* and DS1* low util DTACK* goes lowBring DS0* and DS1* highBring AS* high after DTACK* goes highSet address bits A15-A1 000000000001100 (Offset $18)Pull AS* lowSet data bits D15-D0 0000000000001000 (Turn on controlled data rate mode)Pull DS0* and DS1* low util DTACK* goes lowBring DS0* and DS1* highBring AS* high after DTACK* goes highAnd so on...I see VME is big endian, is this going to screw me up?

author: Benta
author_rank: Super Contributor
timestamp: October 22, 2020, 05:06:32 pm
content: VME is basically the Motorola (today NXP) M68k bus, buffered and with additional help signals. A good start for understanding operation is to study the MC68020 user manual.https://www.nxp.com/docs/en/data-sheet/MC68020UM.pdfSection 5.Why the MC68020? Because it implements the full-fledged M68k architecture and bus operation. Earlier and later CPUs were either multiplexed or had modified bus operation.
Settling Time Measurement Equipment - Page 1
Forum section: electronics / projects

author: Tdeball
author_rank: Contributor
timestamp: January 05, 2025, 09:13:12 pm
content: Hi,This idea spawned on a beginner question posthttps://www.eevblog.com/forum/beginners/settling-time-measurement-assistance/new/?topicseen#newand I have been batting around the idea in my head. I would really love some feedback on if this project/product would be of value to a wider audience or if it is a niche need of mine.The problem: I am designing an extremely sensitive piece of test equipment and require a moderate rise time but more importantly I need to validate the settling time to high accuracy (time to 99.9-99.99% of flat top voltage). The linked topic sent me down a path of app notes for measurement techniques for this application but there is no existing product or open source project for this type of measurement.The idea: I am envisioning an inline dynamic range extender(?), similar to an active probe, with the functionality to take in a signal via BNC connection and dynamically null a user-set DC offset such that the top of the waveform could be more easily measured. Either potentiometers or programmable DAC would set the DC null offset and rise time or a “setup pulse” could auto-configure. A trigger line or self-triggering mechanism would “turn off” the output during the majority of the rise time (~10-90%). An instrumentation amp would compare the 90%-100% signal to the DAC and the output of that instrumentation amp would go to the oscilloscope.I would love some feedback to see if this would be useful to anyone else.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 06, 2025, 02:40:11 pm
content: Settling time referred to what?Your "extender" will have its own settling time, no?You need a high quality scope to do this kind of measurment

author: tggzzz
author_rank: Super Contributor
timestamp: January 06, 2025, 05:19:22 pm
content: Quote from: Tdeball on January 05, 2025, 09:13:12 pmI suggest "numbers, not adjectives".ps, ns, µs, ms, s?nV, µV, mV, V, kV?Dribbling out the specifications little by little is a waste of people's time.I suggest continuing the discussion where it started, to keep everything together. Alternatively, if you really want to re-start from a new fixed point, then re-state everything you now no to be relevant. Expecting viewers to read and remember two threads is unlikely to be productive.
Seven Segment Display (with BCD Decoder) - Page 1
Forum section: electronics / projects

author: rdbanks
author_rank: Contributor
timestamp: June 26, 2018, 07:16:16 pm
content: Hi all!Just a quick one, I'm looking for a 7 Seg Display with a decoder all built into one unit, im just wondering if anyone knows of such device, Ideally the unit will have a connector to just run the output of my device to.I've designed it with the 74HC4511 however if anyone knows of an off the shelf unit or has any other ideas that would be great.The unit ive designed is expansive however this part is essentially a 'shift indicator', this is a small part of the project. The display ideally needs to be a single digit, waterproof (splash proof) unit.Thhhhaaanks!!!Ryan

author: Twoflower
author_rank: Frequent Contributor
timestamp: June 26, 2018, 07:21:48 pm
content: How about this one of these:http://www.ti.com/lit/ds/symlink/sn74ls47.pdfOr a modern one:HEF4543BEdit: I think I misunderstood the question. You're looking for a 7-segment LED with build in BCD decoder? Not sure if such thing exists. Sorry.

author: rdbanks
author_rank: Contributor
timestamp: June 26, 2018, 07:29:50 pm
content: No worries, the HEF4543B might be a good shout though!Thanks!

author: TK
author_rank: Super Contributor
timestamp: June 26, 2018, 07:58:14 pm
content: The old TIL311 is a display with BCD decoder

author: miceuz
author_rank: Frequent Contributor
timestamp: June 27, 2018, 04:44:08 am
content: Just built one recently:https://www.tindie.com/products/miceuz/huge-7-segment-display-module/It's not BCD, but serial, can be daisy-chainedSources are here:https://github.com/Technariumas/7-segment-block
SFP calibration - Page 1
Forum section: electronics / projects

author: alamwte
author_rank: Regular Contributor
timestamp: January 09, 2021, 10:33:08 am
content: Hello everyone,I have a SFP module.I don't have many information about it. I know it consist of a programmable IC that convert electrical signal to optical signal. And also a laser diode that convert optical signal to fiber.Now I want to know that is the TX power defined in IC or in laser diode?And if I want to change the TX power, what thing should I change in my module? Do I need to change my laser diode or can I change these parameter with changing in my IC programming?Thanks.
SFP Datarates - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: November 18, 2021, 08:26:00 pm
content: I need to re-source an SFP due to it going EOL and I'm getting ready to order a handful of options to try.My primary question is if anyone here knows how forgiving these are in regards to their data rates. The system is currently configured for a 2.125Gbps module could I use a multiple of say 8.5Gbps and it should translate fine? Or would the system need to be reconfigured to work with the newer module?

author: ZigmundRat
author_rank: Regular Contributor
timestamp: November 19, 2021, 04:48:14 am
content: From the 2.125G rate I assume this is fiber channel? You should find many available options for this SFP without much difficulty. You might find multi-rate SFPs which cover this and many other rates but they will likely be more expensive. But you can get 1/2/4 gig fiber channel SFP for $50 so it’s not like they are very expensive.But to answer your question directly - no, trying to use 8.5Gbps SFP will not ‘translate fine’. The exception may be a multi-rate SFP, such as the afore mentioned 1/2/4G unit. These have PLL which will allow operation over wider rates.When choosing a replacement you also need to be aware of the other characteristics: multi-mode or single mode; gray or colored; reach, etc.
SFP power supply specs - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 12, 2014, 06:59:19 pm
content: Hello,I am reading this specftp://ftp.seagate.com/sff/INF-8074.PDFwhich I got through wikipedia.How do I interpret this"VccR and VccT are the receiver and transmitter power supplies. They are defined as 3.3V ±5% at the SFP connector pin. Maximum supply current is 300 mA."but"VccR and VccT may be internally connected within the SFP transceiver module."So is it 300mA per pin, or 300mA all together? For my board it would be the difference between adding a linear regulator at the cage, or needing a dedicated switcher for the SFPs, especially if I add more SFPs...I also worry about the rather slack nature of the spec, in that I'm sure the day the PCB gets built someone will find a SFP that needs 400mA per pin...TIA!

author: calmtron
author_rank: Regular Contributor
timestamp: August 13, 2014, 08:09:34 am
content: Check out some SFP datasheets. I had a quick look in one I had on hand and it specified a current consumption of 330 mA, another SFP was specced at 375 mA and some random ones on the Internet had 1.2 W or 1.5 W as max power consumption, so 300 mA per pin seems reasonable.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 13, 2014, 03:37:03 pm
content: Yeah I'm going with 300mA per pin, it's the only interpretation that makes sense, because they don't give a ratio. Could it be 1mA for VccR and 299mA for VccR?Anyhow the module datasheets usually give VccT+R as a total and I've never seen it exceed 600mA, yet.
Sfuminator - Page 1
Forum section: electronics / projects

author: Ax_6
author_rank: Contributor
timestamp: September 19, 2013, 04:45:07 pm
content: Hey guys, I wanted to share with you my latest project that I proudly made from scratch, all the software is wrote by me and I'm planning on putting a little bluetooth board to connect an mp3 player wirelessly. What do you think about it? Do you may have also any suggestion on which module I could use?Still have to find a nice big diffuser... but it finally should look like this

author: gibbled
author_rank: Regular Contributor
timestamp: September 19, 2013, 05:44:54 pm
content: The content owner has not made this video available on mobile.Nice project!
SG1468T voltage regulator - voltage adjust - Page 1
Forum section: electronics / projects

author: jeroen79
author_rank: Frequent Contributor
timestamp: December 18, 2014, 12:48:12 am
content: I found this voltage regulator.Normally it will give +/- 15V but according to the datasheet it has a voltage adjust pin that can adjust both outputs between 9 and 20V.In the circuit diagram the voltage adjust goes to the base of one of a pair of transistors.The other transistor's base is linked to a zener diode going to ground and a resistor going to positive supply.As far as I can see this pair will control the current mirror above it.With the voltage adjust not connected the right transistor would always be off, right?How do I use the voltage adjust? The datasheet doesn't specify this.I can use it to turn the right transistor on before or alongside the left transistor but I cannot force the left transistor open or closed.This puzzles me as the datasheet says I can adjust the voltage up and down.Datasheet:http://www.eoo-bv.nl/documentatie/SG1468T.pdfExtra question: How does this regulator compare to an LM78xx or LM317 and their negative counterparts?Is it useful to make a small split rail powersupply?

author: Unknown
author_rank: Unknown
timestamp: December 18, 2014, 02:45:19 am
content: Check out the datasheet for the equivalent (original?)Motorola MC1468/MC1568, which has some little detail on using it as an adjustable regulator.Though, from the application circuits it looks like it can only be configured for 8v-14.5v or 14.5v-20v, not 9-20v - which makes sense from your understanding/explanation of the internals.

author: jeroen79
author_rank: Frequent Contributor
timestamp: December 18, 2014, 09:10:29 am
content: Thank you.That datasheet has some more information.Here there is connection between the transistor's base, the voltage adjust pin and a stack of zeners and resistors between Vsense and ground indicated by a little 'knot' that is not there on the SG datasheet.I suppose the potentiometer can be used to tweak this stack.
sg3525 fiber splice termination device - Page 1
Forum section: electronics / projects

author: Hypsjw61
author_rank: Newbie
timestamp: November 12, 2024, 01:05:35 am
content: We need to make a fiber termination device using SG3525, TC4427 and 1000V MOSFETs. There will be a 24/750 V transformer at the output of the MOSFETs. Since this is my first physical project, I need your help. Can you help me with a design scheme, especially for the part up to the transformer?

author: jonpaul
author_rank: Super Contributor
timestamp: November 12, 2024, 04:41:06 am
content: Very dangerous to work at 1000V SMPS.Get experience in a lab or firm doing off line SMPS forst, take safety precautions and protect your equipment and life.Minimum equip: 240:240 isolatio trsf, variac, scope, proper current and voltage probes.Jon
sgmg-09A2AB yaskawa  connector pinout - Page 1
Forum section: electronics / projects

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: April 14, 2017, 07:12:52 am
content: Himy friend have an old CNC machine with these sgmg-09A2AB yaskawa motors on it, I wanted to design a brand new board for it. the problem is that It seems I can not find the motor drive pinout, does anybody have it? or how can I figure it out?
Shape of relay contact faces - flat vs convex - Page 1
Forum section: electronics / projects

author: Circlotron
author_rank: Super Contributor
timestamp: December 22, 2015, 03:02:12 am
content: Was looking at an Omron relay and the contact faces of the N/O side are flat but the N/C side are convex toward flat. The lever does appear to have a slight bow so the contact faces may not be parallel but wouldn't this be the same for both sides? Maybe an example of what appears to be mundane is actually a whole lot more high-tech?

author: SeanB
author_rank: Super Contributor
timestamp: December 22, 2015, 04:51:58 pm
content: The faces are designed so they slip slightly when contacting, so that they wipe off any oxide film from the faces. The NC side has the dome so the pressure to wipe is higher, as it is only got the tension in the return spring to wipe the contact surfaces past each other. The NO contacts close with a lot more force, so can have a larger area to get a similar surface pressure.This also explains the difference in contact ratings for the better spec relays, as the NO configuration has a larger wiped area and thus a higher contact rating, while the NC is lower because of both the lower pressure and smaller area.Your one is either new or only has had a low non inductive load applied with low cycles, as the contacts still have the gold flash applied to them to protect against oxidising in storage, as high current use burns this off pretty fast,, depositing it on the clear case as a black film along with vaporised silver alloy of the contact materials.
Share pins for audio input + UART - Page 1
Forum section: electronics / projects

author: jrs45
author_rank: Regular Contributor
timestamp: May 06, 2022, 12:51:07 pm
content: I'm designing an audio amp (w/DSP) with a few input pins (stereo balanced) and thought it would be handy to use a couple of these pins for UART I/O as well, mostly for factory testing, maybe for customer use. I don't want to add another socket or anything.Is there a clean way to do this?The audio goes through a standard RF filter/TVS/DC block into a codec (320AIC3204). The UART would go through an RC filter + protection diodes for microcontroller pin protection, then to the microcontroller.In software, I can set the microcontroller pins to input of course, but I have to worry about the loading effects of this RC network and protection diodes or imposing noise on the audio signal. Maybe it will be OK?I'd rather avoid adding a switch for this.Is there a "standard" way of doing this sort of thing?
shared heatsink between regulators - Page 1
Forum section: electronics / projects

author: Asim
author_rank: Regular Contributor
timestamp: August 10, 2013, 09:13:33 am
content: Hi guys,I built a power supply based on the linear regulators lm317, lm337, 7805 and 7905so I would have positive and negative variable voltages and fixed positive and negative 5 volts.I used a shared heatsink between lm317 and 7805 <<< my mistakeand another heatsink for lm337 and 7905. <<< wasn't a problem by luckafter powering the circuit, the protection in lm317 kept kicking so i checked the PCB with a multimeter to check if there is a short circuitbetween the output and the ground and there was but i couldn't find it in the PCB, then it hit me in the face that the regulators tabs are also one of the terminals (input, output or ground depending on the regulator type), after checking the datasheets i found out the lm317 tab is the output and the 7805 tab is the ground.That was my mistake. By using a shared heatsink between them the heatsink itself shorted them out.After fixing that everything went well.I thought I should post this so people don't do this silly mistake.A QUESTION: Is there something can be put between the regulators and the heatsink to prevent shorting the tabstogether (good material) and if there is what is its name?.

author: ovnr
author_rank: Frequent Contributor
timestamp: August 10, 2013, 09:27:02 am
content: You'd usually use a silpad and an insulating washer for the screw. Try to get the washers specifically made for the purpose - profile looks like a T, so there is a thin tube that fits down into the TO-220 package to prevent the screw from shorting to the tab sideways.You will also find small alumina plates and various clamping mechanisms (pushing on the plastic body of the TO-220 as opposed to the metal tab) used in practice, but they're often more complicated.

author: M. András
author_rank: Super Contributor
timestamp: August 10, 2013, 09:29:28 am
content: silicon thermal conductive pads

author: Asim
author_rank: Regular Contributor
timestamp: August 10, 2013, 11:05:00 am
content: Thanks for the fast response.I found this on Ebay, is it any good ?http://www.ebay.com/itm/TO-220-Transistor-Mica-Insulation-full-set-for-TO-220-Transistor-X-10-/261144589902?pt=LH_DefaultDomain_0&hash=item3ccd6e364eif not can you suggest something for me ?
Shared heatsink grounding - Page 1
Forum section: electronics / projects

author: BorisRap
author_rank: Contributor
timestamp: October 14, 2022, 09:29:09 am
content: Good day.I'm designing a power supply composed of 3 stages:-a PFC with line filter-an isolated LLC resonant converter-a constant current/constant voltage DC/DC converterAll three stages are in series.All switching mode stages are on the same board (it's a fairly large board) and the board is inside an aluminum case without any airflow. For this reason it must be a good thermal connection between all the heat-generating elements and the case.So I've designed it in a way which all switching transistors and switching inductors are thermally coupled to the case. This noisy components are electrically insulated but they are really close to the metal.That's why I'm worrying about switching noise coupling to the case, especially between switching components of two switching converter that are insulated.Do you have any idea how should I connect the case?Of course it must be connected to mains earth. And mains earth is coupled to the PFC ground via the inline filter Y capacitors.Do you have any guidelines on how should I (or shouldn't) couple the two grounds and mains earth?Thank you very much

author: Benta
author_rank: Super Contributor
timestamp: October 14, 2022, 07:05:01 pm
content: I'd be more worried about killing someone touching the case.
Sharing 12mhz oscillator between multiple uC's - Page 1
Forum section: electronics / projects

author: gsm2k
author_rank: Newbie
timestamp: October 24, 2018, 09:17:52 pm
content: Hi!I am using an 12MHz oscillator in my design providing clock to a FT4232 quad uart chip and have recently added a new USB hub controller also requiring a 12MHz clock. The oscillator I'm using is a 3.3V HCMOS typehttps://abracon.com/Oscillators/ASFL1.pdfCan I safely share this oscillator between the IC's or are there some potential issues I'm not considering? I will off course keep the lines as short as possible.

author: Bassman59
author_rank: Super Contributor
timestamp: October 24, 2018, 10:01:42 pm
content: Quote from: gsm2k on October 24, 2018, 09:17:52 pmUse a multi-out buffer such asthis.

author: BocaDev
author_rank: Contributor
timestamp: October 25, 2018, 12:03:30 am
content: QuoteI have in the past taken the output (xtal) drive pin of one chip that has the xtal connected to it and coupled it to the input pin (xtal) though a 100pf cap. The output (xtal) pin is left unused. If you look at the data sheet of each IC, there are two pins for connecting an external xtal to the IC. One pin is xtal input, and the other pin is labeled as xtal output.
Sharing a current shunt? - Page 1
Forum section: electronics / projects

author: Things
author_rank: Regular Contributor
timestamp: December 10, 2012, 03:01:12 pm
content: Hey guys,I'm working on an electric scooter project, and seeing as it'll use LiPo packs (And lots of them!), I'm taking protection very seriously. I have found a battery protection/monitoring IC from TI that fits my needs perfectly.However, on this same board I also want a uC, to do various things like current, speed, temp readouts etc.So what I'm wondering, is the battery monitoring IC has inputs for a current shunt, which it can monitor and shut off the discharge FET, but I also want to be able to give a current readout on a LCD from the uC.Is there any accurate way I could share readings from a current shunt between both devices? 2 shunts in series possibly, one for each device?Cheers,Dan

author: grenert
author_rank: Frequent Contributor
timestamp: December 10, 2012, 03:54:08 pm
content: Since the measurement of a current shunt is voltage, as long as your voltage measuring device is reasonably high impedance you should not have a problem.

author: Things
author_rank: Regular Contributor
timestamp: December 10, 2012, 04:10:09 pm
content: Oddly enough neither chips seem to specify input impedance.

author: c4757p
author_rank: Super Contributor
timestamp: December 10, 2012, 05:23:42 pm
content: Measure it. Ohm's law is your friend.

author: Neilm
author_rank: Super Contributor
timestamp: December 10, 2012, 05:28:25 pm
content: Some of the battery monitor chips TI do can report the current value to a supervisor MCU. If you want to share the current shunt there should be no problem provided you have a high impedance. If you are not sure, you could always use an op-amp to buffer it.Neil