hybridfree/eevblog-posts huggingface dataset:
Asking for Help Identifying a Magnetic Bubble Memory Board - Page 1
Forum section: electronics / projects

author: TurboTom
author_rank: Super Contributor
timestamp: October 25, 2024, 11:48:46 am
content: Basically, the title tells it allBut to go into a little more detail and to explain my motivation, here we go...Being the type of guy that likes playing around with obscure items (like many around here probably), I felt to want to explor into "historic" memory technology and some time ago got myself the little bubble memory board shown in the attachment. It's conformally coated and most of the chips used are of the military / extended temperature range variety. Thus, I've got the impression that this item belonged to some "serious" application.Since I would like to interface to it and get it to work one way or the other, I thought to ask here for hints -- maybe someone may have an idea where this board might have been removed from. Moreover, I still couldn't find a datasheet for the Plessey sense amplifier (CL9001-3). Maybe someone got an old data book that actually contains information on that chip? All my web searches came out unsuccessful, yet I could identify the chip as a sense amplifier by means of logical thinking (of course) and an ad in the 02/82 issue of "Digital Design" (attached).I'ld also like to know if someone recognizes the logo on the three magnetics components (pulse transformers or whatever) and can assign it to a company. It looks somewhat familiar to me but I couldn't actually identify the (probably long-gone) company that it belonged to.So thanks a lot for any information that you may contribute!Cheers,Thomas

author: ebastler
author_rank: Super Contributor
timestamp: October 25, 2024, 12:05:54 pm
content: Google says the logo is Newport Components, acquired by C&D Technologies and then Murata.Some other NOS products here:https://www.silicon-ark.co.uk/newport-componentsAnd a brief press statement on the Murata acquisition:https://www.procureinc.com/manufacturer/Newport_Components_-_C_and_D_Technologies_-_Murata_PS/Can't help with the PCB and the Plessey chip, I'm afraid.EDIT: This backplane is labelled "TES QCO-749". Your module has "TES QCO747" in the lower right. Could they be related?https://aeliyamarinetech.com/products/honeywell-51401477-100-d-backpanel-51401475-100-rev-c
ASK/OOK implementation with discreet logic - Page 1
Forum section: electronics / projects

author: smoothVTer
author_rank: Regular Contributor
timestamp: September 13, 2019, 05:17:37 pm
content: In a current project I am working on, I am stuck with using a family of uC's that do not have built-in IR modulation logic. I know I can use timers & compare registers to do ASK/OOK modulation, albeit the solution is messy to make the carrier & envelope signals work together in the uC & firmware. So I thought of a possible solution that may make the modulation easier using external discreet external logic, but precisely what logic to use in what combination confuses me.Thus I am asking for help from all you digitally-minded folk out there in EEV-Land!Assuming that:(a) There is always present a 36kHz carrier signal on a uC pin;(b) The envelope signal would have a minimum HIGH or LOW time of >= 1 ms;(c) If the envelope signal goes high in the middle of a carrier pulse HIGH time, the output is latched low until the next rising edge of the carrier, at which point the output goes high(d) If the envelope signal goes low in the middle of a carrier pulse HIGH time, the output is latched high until the next falling edge of the carrier, at which point the output goes lowTo illustrate this behavior with a diagram:Area labeled #1: Output waits until the next rising edge of the carrier before it is assertedArea labeled #2: Output waits until the next falling edge of the carrier before it is de-assertedArea labeled #3 & #4: Normal gating operation of envelope on carrierGiven that the carrier and envelope already exist on the uC pins, how would the output waveform be constructed using the minimum number of flip-flops & logic gates?

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 13, 2019, 07:09:20 pm
content: Sure. This is a typical thing. You only need a flip-flop and an AND gate. Like so:For the flip-flop, you can use a 74LVC1G74 for instance, and a 74LVC1G08 for the AND gate.

author: smoothVTer
author_rank: Regular Contributor
timestamp: September 13, 2019, 09:16:09 pm
content: Thank you!Simulation works out; I forgot LTSpice allows logic sims like this. Neat.Just for clarification: The DFF is required to be rising-edge triggered in this implementation, correct?

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 13, 2019, 09:25:03 pm
content: Quote from: smoothVTer on September 13, 2019, 09:16:09 pmYes and yes. For LTSpice, yes it has basic logic gates in the Digital category. Just one thing to know is that they have a default logic high level of 1V. You can change this in the component attributes dialog (but for just logic simulation, you don't care about that...)Due to the propagation delay of the flip-flop (however small), this circuit should be actually glitch-less. I'll leave it as an exercise to figure out the corner cases.
Assembled 2N3906-transitor based temperature sensor - Page 1
Forum section: electronics / projects

author: prasimix
author_rank: Unknown
timestamp: January 26, 2019, 04:50:45 pm
content: I'm wondering if anyone is aware of ready-made (assembled, ready for mounting) 2N3906-transitor based temperature sensor, i.e. that is not intended for PCB temperature measurement, but as standalone sensor that can be mounted somewhere inside enclosure. I'd like to use it with I2C fan controller. Ideally, it has to be similar to thisonebut with transistor instead of NTC. Thanks in advance.

author: nsrmagazin
author_rank: Regular Contributor
timestamp: January 27, 2019, 07:11:14 am
content: Whats wrong with using LM335? Its used for batteries and power supplies.

author: prasimix
author_rank: Unknown
timestamp: January 27, 2019, 07:16:25 am
content: Nothing is wrong with LM335, but I need external sensor that is going to be connected to I2C fan controller that is expecting 2N3906 "diode" temperature sensor. I'd like to skip soldering of mentioned part to the wires and connector but looking if such assembled solution exists.

author: zitt
author_rank: Regular Contributor
timestamp: January 31, 2019, 09:07:55 pm
content: Confused... it's three pins soldered in a diode configuration (IE two wires).I don't see any value in complicating that. It's intended to be "easy".Just make a quick PCB with a 2pin connector and the 3pin transistor and wire it. Done.What am I missing?

author: mvs
author_rank: Frequent Contributor
timestamp: January 31, 2019, 09:58:52 pm
content: Quote from: zitt on January 31, 2019, 09:07:55 pmIts too much effort... I would use some BJT in TO-126 package (like BD-139) and solder wires directly to pins.

author: prasimix
author_rank: Unknown
timestamp: January 31, 2019, 09:59:31 pm
content: You're just missing a quantity: try to do that few hundred times, together with making cable assembly.

author: prasimix
author_rank: Unknown
timestamp: January 31, 2019, 10:00:37 pm
content: Quote from: mvs on January 31, 2019, 09:58:52 pmYeah, that is much convenient then SMT part, and it already has a mounting hole.

author: Yansi
author_rank: Super Contributor
timestamp: January 31, 2019, 10:05:44 pm
content: I don't see anything particularly complicated on hand-assembling a panel of 100 SOT23 transistor plus 100 connectors. That is just 200 components. Way less than some single-unit test PCBs I am used to hand assemble (500 components on a single board).Quick search turned nothing, so I would go down the route of having a custom PCB panel made, probably it could even be extremely cheap to get assembled using the JLCpcb service.You could even get custom cable assemblies crimped and prepared. There are cheap enough services for that already available for bargain.
assembly drawings, diode polarity and pin 1 indication? - Page 1
Forum section: electronics / projects

author: incf
author_rank: Frequent Contributor
timestamp: April 08, 2025, 11:50:20 am
content: I'm looking to minimize the number of questions that a manufacturer needs to ask when building prototypes.What steps do you take to clarify things like diode polarities and pin 1 locations? (in assembly drawings or elsewhere)

author: electron_plumber
author_rank: Regular Contributor
timestamp: April 08, 2025, 01:55:36 pm
content: A silkscreen/assembly drawing dot is universally understood to mark pin 1.Confirm which pin is 1 on the datasheet (usually the cathode) and configure the symbol/footprint accordingly. I prefer the dot over the line because it takes up less space and can be more easily moved if its in the way.

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 08, 2025, 02:02:55 pm
content: A dot is universally pin 1 but pin 1 is not universally the cathode (sadly). A bar on the silkscreen is my prefered solution...

author: incf
author_rank: Frequent Contributor
timestamp: April 08, 2025, 02:38:26 pm
content: Suppose they ask for clarification anyways despite the silkscreen being marked? (because maybe they only look at the assembly drawing)

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 08, 2025, 07:27:18 pm
content: Depends on the "they" in question? PCBWay sends pictures of a sample assembled board with polarities of diodes and LEDs etc marked.

author: incf
author_rank: Frequent Contributor
timestamp: April 09, 2025, 12:10:35 pm
content: Does anyone draw diode symbols in the assembly drawing?Or write the word "CATHODE" on each symbol in the assembly drawing?I'd really like board houses to be able to confidently (and correctly) ascertain which end is the cathode from the drawings without having to ask each time.

author: bson
author_rank: Unknown
timestamp: April 09, 2025, 11:55:44 pm
content: Quote from: incf on April 09, 2025, 12:10:35 pmYou can update the footprint to have a "K" on the cathode pad in the FAB layer.Yes, it should be the one with the bar. This bar should line up with the bar printed on the package (whether SMT or axial THT).The square pad is usually pad 1 and whether pad 1 is A or K varies. My personal preference is for A to be pad 1 (square) and K to be pad 2 (round), but the silkscreen bar is a more reliable indicator.

author: PGPG
author_rank: Frequent Contributor
timestamp: April 10, 2025, 03:40:45 pm
content: Quote from: incf on April 09, 2025, 12:10:35 pmThere are so many people making assembly drawing that I would be surprised if the answer here would be: No, nobody does it.For many years (2005 to 2017) at PCBs we send to contract manufacturer we were not using silk at all. We marked cathode with bar at assembly drawing and never had any problem with it.
Assembly Houses - Page 1
Forum section: electronics / projects

author: Strube09
author_rank: Regular Contributor
timestamp: December 09, 2010, 12:56:58 am
content: Hello,Dave can you tell me who you have do your assembly for small runs? I find most places to be way to expensive and my china vendors only will run my production quantities. I need to find a good assembler for some pre-production test and releases.Anyone else have a good small quantity assemblers?Thanks,Strube09

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: December 09, 2010, 01:35:18 am
content: Where are you located?

author: Strube09
author_rank: Regular Contributor
timestamp: December 09, 2010, 02:17:35 am
content: Quote from: Jon Chandler on December 09, 2010, 01:35:18 amMichigan, USA

author: EEVblog
author_rank: Unknown
timestamp: December 09, 2010, 09:19:51 pm
content: I have a guy in Melbourne who does hand assembly for me for very little cost.Works out of his garage (probably part time).There must be people in the US who do a similar thing?Try asking on the sci.electronics.design usenet group perhaps?Dave.

author: osmosis321
author_rank: Regular Contributor
timestamp: December 09, 2010, 09:41:43 pm
content: I'll do it. Message me.
assembly issue on metal core - Page 1
Forum section: electronics / projects

author: Jessie Barry
author_rank: Newbie
timestamp: June 30, 2016, 02:36:46 am
content: we have little assembly issue due to the metal core and solder melting issue.You have any idea what is the best way to assemble metal core boards?

author: Eva Liu
author_rank: Newbie
timestamp: June 30, 2016, 02:40:17 am
content: I also face the same problem, any one can help?

author: Berni
author_rank: Super Contributor
timestamp: June 30, 2016, 05:07:16 am
content: You will in most cases have to use a special temperature profile when reflow soldering them since the metal inside them takes a long time to heat up.As for hand soldering its best to get a board preheater. Its a device that you set your board on top that then uses heaters or hot air to heat the board from the bottom side. Keeping the whole board at like 100°C helps hand soldering a lot since the core wont take away heat as quickly.

author: Jessie Barry
author_rank: Newbie
timestamp: June 30, 2016, 08:05:33 am
content: Quote from: Berni on June 30, 2016, 05:07:16 amThanks Berni, we will try your suggestion.
Assignment help (A Brief overview of the theory of the P-N junction diode). - Page 1
Forum section: electronics / projects

author: garethevans177
author_rank: Newbie
timestamp: February 15, 2020, 04:40:46 pm
content: Hello,Could anyone please help, as part of my foundation degree mechanical systems engineering, I am currently working on my electronics module. As it is a distance learning degree I am finding it difficult to grasp. Could any one help me in any way with the following question?P-N junction forward bias characteristicsThe diagram in figure 1 provides the voltage and current measurements shown in table 1.Figure 1Table 1Give a brief overview of the theory of the P-N junction diode. Plot the data generated intable 1 using Microsoft Excel. Extrapolate the straight-line part of the graph to interceptthe voltage axis and estimate the turn on voltage for the diode tested. Can you estimatethe resistance of this diode? How does the theory relate to the experiment?V1D11N4148XMM1XMM2Vd (V) Id (A)0 00.1 1.04E-100.2 4.28E-100.3 1.12E-080.4 5.21E-070.5 2.40E-050.6 1.09E-030.7 1.83E-020.8 6.13E-020.9 1.14E-011 1.70E-01

author: rstofer
author_rank: Super Contributor
timestamp: February 15, 2020, 05:47:50 pm
content: This w2aew video may help

author: rstofer
author_rank: Super Contributor
timestamp: February 15, 2020, 08:59:35 pm
content: Here is the spreadsheet. I didn't add all the fancy labels because graphs with Excel are a PITA. Learn MATLAB or, for free, learn Octave, an opensource work-alike.In any event, it shows the characteristic curve we expect as a diode gets increasingly forward biased. Print the graph and just use a pencil and straightedge to estimate the resistance R = E / I. You pick a couple of points on the slope of the line, figure out the change in current and the change in forward voltage. Do a little division and you get the dynamic resistance. It will be a low value of Ohms. Around 4:30 in the video...As to the theory of the junction, that stuff is all over the Internet.
Assistance for protection on an inductive, polarity switching load. - Page 1
Forum section: electronics / projects

author: ApexM0Eng
author_rank: Contributor
timestamp: June 10, 2015, 07:56:45 pm
content: This section of a circuit I have has two relays switching the contacts of an inductive load.Now for a normal inductive load, I understand you would use a flyback diode for protection.I am puzzled how the protection would change for a case such as this.Has anyone dealt with this before or know what might be done?

author: Ian.M
author_rank: Super Contributor
timestamp: June 10, 2015, 08:38:58 pm
content: I assume the supply is DC. Take a bridge rectifier and connect the AC terminals across the inductor and the + terminal to the incoming +12V and the - terminal to 0V.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 10, 2015, 10:11:11 pm
content: ^^The most general case, with AC power as well (e.g., "three way switch" for house wiring), has to use a bidirectional device, like an R+C snubber or MOV. The latter would be good for very heavy loads; the former is popular for small things like relay coils.Tim

author: ApexM0Eng
author_rank: Contributor
timestamp: June 10, 2015, 10:36:23 pm
content: Quote from: Ian.M on June 10, 2015, 08:38:58 pmYes its a DC Source.Something like this?*That should read 1n4004

author: calexanian
author_rank: Super Contributor
timestamp: June 10, 2015, 11:00:00 pm
content: You can go that route. You could also just use a TVS or an MOV of appropriate voltage and joule across the coil. We actually use both in various places in our designs.
Astable oscillator + H bridge in one IC? - Page 1
Forum section: electronics / projects

author: tinkrmind
author_rank: Newbie
timestamp: October 24, 2019, 08:11:39 pm
content: Hello everyone! I'm designing a piezo buzzer driver circuit. I want a GPIO pin to drive the piezo, to switch it on and off. The constraints of the design are to have minimal size and quiescent current. I'm think a good solution would be to use a 555 timer to generate a square wave, use a not gate to get the logically opposite signal, and feed these to an H bridge that drives the piezo. But this would require two large ICs(555 and H Bridge). Is there a chip that combines this functionality so it has two logically opposite signals?I searched digikey for H -bridge oscillator, and similar terms but didn't find anything.I know that this would be easily done with a small microcontroller, but I'd rather not have to code 500 microcontrollers!Thanks in advance!

author: magic
author_rank: Super Contributor
timestamp: October 24, 2019, 08:38:32 pm
content: I was recently thinking about similar problem and an idea I came up with but not tested yet is to use an integrated half bridge driver.Those things have one input and two outputs. If the input is low, the "low" output is driven high and the "high" input is driven low. If the input is high, vice versa. This is intended to drive a pair of FETs implementing a half bridge, but connecting load directly between the two driver outputs makes it a full bridge. There will be "dead time" during transitions when both outputs are held low for a microsecond or so.An RC network between the low output and input will ensure oscillation if the driver has input hysteresis. They usually do.Then there is IR2151, a self-oscillating half bridge driver, designed for self-clocking. Not sure if there are alternatives for 5V, though. You can certainly get normal drivers rated for 5V operation and do the input hysteresis trick.The "high" output has separate supply, called Vs and Vb in IR datasheets. This would go to GND and VCC.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 24, 2019, 08:43:14 pm
content: You can drive many small piezo buzzers with digital outputs directly.

author: jkran
author_rank: Newbie
timestamp: July 01, 2021, 02:02:12 pm
content: Old thread but I tested this (using IRS21531D) and wanted to share results.I attached the schematic I used tieing ground to VS and Vcc to Vb. This worked to get the desired waveform with Vcc from 11V to 15V. It triggered the PDLC but not fully clear as the film needs closer to 18V+. Does anyone have advice on an IC that I can run at 24V DC?@magic Thank you for the tip!

author: Zero999
author_rank: Super Contributor
timestamp: July 01, 2021, 02:49:30 pm
content: Piezo buzzers don't require much driver. A Schmitt trigger logic IC will do. Here's an example with the 74HC14. If you want to use a higher voltage, change it for the HEF40106B. The spare gates, in the hex package, can be connected in parallel with those driving the piezo, to provide a little extra drive.
Asteroid Impact Warning Device - Page 1
Forum section: electronics / projects

author: Len
author_rank: Frequent Contributor
timestamp: June 19, 2024, 07:05:24 pm
content: Know when to panic! 🌎🌠😱I built a device to warn of potential Earth-threatening asteroids. It monitors NASA JPL’sSentry web serviceusing a Raspberry Pi Pico W and CircuitPython.Click here for details.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 20, 2024, 09:11:31 pm
content: Nice project, but why such a measly blue botton?This needs a:

author: Phil1977
author_rank: Frequent Contributor
timestamp: June 21, 2024, 08:23:40 am
content: Or you could turn it into a relaxation helper:Let a big *green* light blink up each minute if the number of asteroids has not increased.You will instantanously be relaxed knowing:- Your wifi is working- The city has power- NASA has their servers running- Theres no DOS-attack on your internet- civilization is still there

author: CaptDon
author_rank: Super Contributor
timestamp: June 21, 2024, 01:28:40 pm
content: Most folks are more likely to encounter Hemmroid Impacts.

author: Len
author_rank: Frequent Contributor
timestamp: June 21, 2024, 03:45:51 pm
content: Quote from: Doctorandus_P on June 20, 2024, 09:11:31 pmThere will be plenty of PANIC the first time this thing goes off in the middle of the night.It makes quite a loud red-alert sound.

author: Bud
author_rank: Super Contributor
timestamp: June 21, 2024, 03:53:08 pm
content: Sweet Jesus, that is one of the projects that would never crossed my mind

author: Len
author_rank: Frequent Contributor
timestamp: June 21, 2024, 03:54:07 pm
content: But now you're worried about asteroid impacts, aren't you?

author: shakalnokturn
author_rank: Super Contributor
timestamp: June 21, 2024, 09:02:23 pm
content: In the other great ideas category I stumbled on this one in the early morning hours...
AT25SF081B identification?! (Atmel/Adesto) - Page 1
Forum section: electronics / projects

author: ebastler
author_rank: Super Contributor
timestamp: May 20, 2023, 10:38:21 am
content: Atmel have done a nice job confusing their customers in the serial flash business: Atmel > Adesto > Dialog Semiconductor > Renesas within 10 years, with the last two acquisitions happening within just a 2-year space.Along the way, they have also made a brilliant version change to the AT25SF081, replacing it with the AT25SF081B. Both are largely standard SPI serial flash chips, but with three extra "Security Register" pages of 256 bytes each. I use them in an FPGA design to be compatible with the "TinyProg" open source in-system programming solution; TinyProg puts board and configuration meta-data into the security pages.When Adesto replaced the AT25SF081 with the updated AT25SF081B, they decided to keep the device ID unchanged, but make the chip incompatible. (The security registers are addressed differently now, with addresses shifted by 4 bit.)They also released an application note which mentions that the SFDP Table (Serial Flash Discoverable Parameters) is an option to distinguish the two versions -- but does not document what the SFDP table for the B version actually looks like, or what to expect from the non-B version (which does not support SFDP at all). Neither do the datasheets -- "contact Adesto".Has anyone, by any chance, found a simple and reliable way to distinguish these two chips in software? I could start fiddling around, but don't feel comfortable relying on undocumented behavior: Which aspects are stable, which ones might change from batch to batch? (Response of the older chip to an invalid command; response of the newer chip with some unknown data structure -- which may contain parts that are always the same and parts which are batch-specific?)Thanks for any pointers you might have!

author: ebastler
author_rank: Super Contributor
timestamp: May 21, 2023, 03:12:36 pm
content: Quick follow-up for future reference: I found a description of the SFDP (Serial Flash Discoverable Parameters) from a 3rd party, Macronix. JEDEC apparently wants to limit access to the parameter definitions and Adesto is playing by their rules, but Macronix seems less concerned. Macronix application note AN-114 if anyone is curious.Anyway, after sending the SFDP read command ($5A) and a 4-byte address, the device's response always starts with a header which begins with the 4 bytes 'S', 'F', 'D', 'P'. That is definitely universal and stable. And since all I need to know is whether the device supports SFDP at all (new AT25SF081B) or doesn't (old AT25SF081), checking for those 4 bytes in the response is all that's needed. Case closed.
AT27C020 equivalent still available  - Page 1
Forum section: electronics / projects

author: Miti
author_rank: Super Contributor
timestamp: March 09, 2023, 06:19:22 pm
content: Is there any FLASH equivalent for the AM27C020 used in HP34401 that can still be purchased from Digikey/Mouser/Element 14? Bigger capacity is ok but must be 5V.Cheers,MitiEdit: AM27C020 and not AT27C020

author: BrianHG
author_rank: Super Contributor
timestamp: March 09, 2023, 10:12:38 pm
content: Sorry, I only see stock of the original at the locations listed here (click 'show all' to expand view)https://octopart.com/at27c020-90pu-microchip-77758193?gclid=Cj0KCQiApKagBhC1ARIsAFc7Mc7b4_70_DrzotFvtprDLTOT_8yhwiGRkebRmRl54WNA_S29hkOJplMaAlJUEALw_wcBIt's that 5v support and flash...For originals...Quest components has stock here:https://www.findchips.com/search/AT27C020Microchip (direct, (Now if you cannot trust the company who makes the chip, well, then I do not know what to say...)), Online Components, Rochester, Quest components, and a bunch more stock of the 4mb version here:https://www.findchips.com/search/AT27C040

author: BrianHG
author_rank: Super Contributor
timestamp: March 09, 2023, 11:13:46 pm
content: Can you explain to us why you just didn't go with the AT28C0x0 EEProm series?The 'AT28C010' has plenty of stock, though, you would need to piggyback 2 of them with a logic gate for swapping the enable on the upper address.The 020 and 040 are too hard to get and at over 100$ each, I would stick with the cheap eproms.It would be cheaper to use a serial prom to fill a static ram at power-up and simulate your parallel pages flash ram.

author: BrianHG
author_rank: Super Contributor
timestamp: March 09, 2023, 11:29:53 pm
content: What's wrong with these guys?https://www.findchips.com/search/SST39SF020https://www.findchips.com/search/SST39SF0405v variants exist, but all in surface mount. You will need to make an adapter PCB.Read the data sheet about programming, it is not like an Eprom, only reading is like an Eprom.Make sure you have a programmer which can do the writing...

author: Miti
author_rank: Super Contributor
timestamp: March 10, 2023, 01:05:07 pm
content: I don't know where AT came from, the original one is AM27C020 in PLCC 32 package.Anyway, thank you for the suggestions, I think SST39SF020 would be a good fit.Miti
AT89C2051 programmer - Page 1
Forum section: electronics / projects

author: Md Mubdiul Hasan
author_rank: Regular Contributor
timestamp: March 10, 2017, 02:48:47 am
content: Hi,Even its 1950's project, I feel interest on it. You might feel it silly!I am trying to get attraction those people, who knows its hardware well.Its a serial interface project, someone who posted it online.Take a look this schematic, I have few questions.1. Does the resistors R1 and R2 has connection with PIN4 of DM7406? Did you see those are connected with regulator input?2. Whats the reason of invert signals by buffer here?3. Does the pull-up resistors are on matched value against IN/OUT current and voltage ? I got MAX and MIN pull-up resistor value setting equation on DM7406.4. Anything wrong you could see in this design?Kindly post your comment here.
Atari Lynx Power Circuit - Page 1
Forum section: electronics / projects

author: @rt
author_rank: Super Contributor
timestamp: April 06, 2024, 12:15:40 am
content: Hi GuysI could have sworn the forum had a specific vintage computing section. Was it removed?I have an Atari Lynx with momentary pushbutton on, and a separate momentary button off.most of this circuit is a complicated latch, and some diode protection, with a suicide diode.At the end of the day though, it's just a cheap Zener regulator at the far right of the schematic.It's prone to failure, overvolting the unobtanium silicon with the ~9V battery supply.I want to replace this with one of the Tracopower switchers that are designed to replace a 7805.I'm just unsure if what I'm doing will interfere with whatever is going on for latch feedback at TP19.Should I keep the 120R, remove the Zener, and connect the reg input across where the Zener was?

author: @rt
author_rank: Super Contributor
timestamp: April 06, 2024, 12:53:25 am
content: ps. it looks to me now that TP19 controls oscillation like in some large linear power supplies.That makes things more complicated. It would be fairly easy to do a FET button switch and reg on a small board,but not as easy to integrate a reg here.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 06, 2024, 03:17:39 am
content: The simplest solution would probably be to add a TVS or zener diode for overvoltage protection and a fuse on the input. Then only minimal changes would be needed.If you're going to completely rework the power circuit, consider using 1S lithium with a boost converter.

author: @rt
author_rank: Super Contributor
timestamp: April 06, 2024, 04:54:17 am
content: I have indeed considered a crowbar. It would prevent the worst of the potential damage,but not a complete solution. It appears it's a very common problem.I might actually breadboard this circuit and experiment on the right hand side.

author: Kim Christensen
author_rank: Super Contributor
timestamp: April 06, 2024, 05:31:35 am
content: Also, be aware that the switching regulator pass transistor (Q11) is in the negative lead of the supply.If you put a 7805ish Tracopower switcher in the positive rail that may have consequences.ie: Where does the emitter of Q4 connect to? What else might be referenced to the positive rail?QuoteNo, it not that simple... The zener is part of the feedback circuit for the crude switching regulator made up of U6 (pins 1 thru 6, 8&9), Q11, L6, D14, etc. When the 5 volt output gets too high, the zener conducts, turning Q13 on, which via the feedback path, reduces the on time of Q11 so that the output voltage stays stable. Opposite happens if the 5V output drops too low.

author: Bud
author_rank: Super Contributor
timestamp: April 06, 2024, 05:38:23 am
content: Quote from: @rt on April 06, 2024, 12:15:40 amIt is a child board in "Computers" section.
Atari Punk Console with sequencer to multiple inputs  - Page 1
Forum section: electronics / projects

author: bcnx
author_rank: Newbie
timestamp: September 08, 2018, 12:57:17 pm
content: Hi all,I designed an APC circuit with two APCs on it and a step sequencer, which basically cycles through a series of potmeters with a 5V voltage to it.When I route the sequencer to one discharge pin on the 555 IC, it works fine, but I would like to be able to route it to more potmeters (4 in total).When I do that, things stop working.I figured a solution might be to use a buffering opamp. This does not work however, because the output current is too high. When I lower the current with resistors or voltage dividers, the sounds comes back, but it is different from where the sequencer connects to one discharge input on the 555.What is needed, I think, is a way to copy/buffer the voltage AND current of the sequencer to every 555 discharge input.Anyone a hint on how to do that?cheers,BCThis is the circuit:https://www.circuitsonline.net/forum/file/34912/forum-post
ATF1504 can i re-use the programming pins? - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: October 04, 2025, 09:58:35 am
content: I'm toying with a quick project using a ATF1504AS and some memory chips...But I need absolutely all the pins.On my other designs I have saved TDI, TMS, TDO and TCK exclusively for programming but this time I need to use them as I/OThe datasheet doesn't seem very clear but does suggest they are useable.Is there something simple I am missing? How do I ensure the device does or doesn't go into programming mode?Thanks in advancePSOn other devices I have seen PRG_SEL?

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2025, 03:33:00 pm
content: Seehttps://github.com/peterzieba/5Vpld/blob/main/PROGRAMMING.mdsection 'Fitters and their options'.N.B. to re-enable JTAG you need to apply acurrent limited12V supply to OE1. Seehttps://www.hackup.net/2020/01/erasing-and-programming-the-atf1504-cpld/orhttp://forum.6502.org/viewtopic.php?t=4349&start=30

author: NivagSwerdna
author_rank: Super Contributor
timestamp: October 04, 2025, 07:09:33 pm
content: >>> or you need to know about the secret that involves applying +12V to the OE1 pin to re-enable the JTAG pins temporarily.Wow! That's some dark magic.Thanks! So I can do it... although might want to get it right first time!Thanks
ATI PCI 3D RAGE II  RAM Upgrade to 4MB - Page 1
Forum section: electronics / projects

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: April 02, 2023, 10:11:27 am
content: Out of curiosity, i couldn't resist to attempt a RAM upgrade of the graphics card of my vintage DOS box. card in question is an ATI PCI 3D RAGE II with 2MB. pcb is PN 109-38200-00, video BIOS is a PCI MACH64 GT, 113-38204-102. base 2 MB RAM on card is 2 x HITACHI 1024 kB SG-RAM. i upgraded the empty footprints with two OKI SG-RAMs. i saw on photos of fully populated cards that R92 wasn't populated, so i removed resistor R92 from my card as well (which, in hindsight, is probably not required).naturally, i screwed things up and had CLK not properly connected to one of the two added RAMs. however, MACH64DIAG.EXE happily reported the card as still having only 2 MB and RAM all being OK, while the graphics test showed some almost non-visible "noise" in the screen colors. also, the card does _not_ report such a RAM fault at boot time. without knowing about the CLK fault, i also suspected that the card would probably have a 2MB limit hard-coded in its BIOS, but that's obviously not the case. finally, some continuity-checking revealed the uncconnected CLK, and after some resoldering, the RAM test reported indeed 4 MB.BIOS chip is a MACRONIX MX27C512PC-12 w/ VPP=12.5V. i attempted to extract the BIOS with my TL866II, attached is the extracted bin file for whomever might find this post useful.
ATMEG328P - Sensor Board - Page 1
Forum section: electronics / projects

author: CardCastleStudios
author_rank: Newbie
timestamp: August 05, 2020, 06:08:08 pm
content: Hey, All I am building a sensor board using a 16 port RJ45 and wondering if some of the specs that I am using are correct before I send out my Board for production.Board: 1oz CopperTrace Size: .254mmPower Trace Size: .5mmGND is filled on Top and Bottom.Power is coming in from an ATX power Supply using the 6 pin that goes to Data connection allowing for +3.3v,+5v, 12v, and GND.I have the Schematic and PNGs of the board attached.

author: OM222O
author_rank: Frequent Contributor
timestamp: August 05, 2020, 08:17:35 pm
content: Are the ethernet ports on the bottom edge of the PCB?If so I'd be worried about lenght / impedance matching of those traces, seems very willy nilly and all over the shop. Also personally I'd use 30mills for the power traces.

author: CardCastleStudios
author_rank: Newbie
timestamp: August 06, 2020, 06:02:49 am
content: The bottom is the Ethernet jacks, the traces at the bottom of the board are leds which I didn't think mattered to much other than delivering power, pin 8 which is the top most pin for the Ethernet ports is the signal wire going into the mux. As for the other 3 mux they delegate what sensor I have plugged in based on a 3 bit truth table.Is there a reason for the smaller traces on voltage or would that provide less interference?As for setup, this is the second board I have done and could not really see a much more efficient way other than using a bunch more vias which many people say to avoid?
ATmega32u2 usb serial bootloader ?? - Page 1
Forum section: electronics / projects

author: Swaroop 21
author_rank: Regular Contributor
timestamp: July 16, 2024, 12:44:05 pm
content: As per my previous post regarding the APM 2.8 Flight controller reused as a Arduino Mega. I have managed to locate the ISP pins of both the mega2560 and the 32u2. I didn't have any issue uploading the bootloader I also uploaded a blink sketch to blink the onboard led of the APM board which are connected to its PA3 pin. But had no success blinking the led even after uploading the sketch. Other thing as per the APM schematic a mux IC is used to route the uart pins from the mega2560 to either the mega32u2 or an external connector by simply pulling the PPM_PC2 pin high it will connect the uart pins from the mega32u2 to the mega2560. Now where do I find the bootloader for the 32u2 as a usb to serial converter so I can upload programs via the onboard usb rather than hooking up a usbasp programmer. Also what can be the reason for the leds not blinking with the correct pin numbers, I tried both the AVR pin number (PA3) and the arduino pin number (25) but none of them seem to blink the blue led on board where as the previous APM firmware which was in the at2560 the led were blinking when I powered the board on. But not with Blink sketch and the Arduino Mega bootloader.I have attached the Schematic diagram of the APM Board below:

author: Andy Chee
author_rank: Super Contributor
timestamp: July 16, 2024, 03:58:24 pm
content: Quote from: Swaroop 21 on July 16, 2024, 12:44:05 pmInside the Arduino IDE development software, the bootloader can be accessed from the menu, Tools -> Burn Bootloader.I used this video as a guide (despite the language accent):In my scenario was a bit complicated by the lack of a programmer, so I ended up using a second functioning Arduino that was programmed with the ArduinoISP sketch.

author: Swaroop 21
author_rank: Regular Contributor
timestamp: July 17, 2024, 05:00:24 am
content: The bootloader in the video is for 16u2 not 32u2 won't it affect its working ?? or can i upload the 16u2's bootloader to 32u2 as 32u2 just has more memory so i don't think it should have any problem ??

author: Andy Chee
author_rank: Super Contributor
timestamp: July 17, 2024, 12:44:47 pm
content: There should be a 32u2 bootloader in the Arduino IDE directory. The video instructions are the same, just use the 32u2 bootloader.
Atmega32u4. Correct way to sharing SPI pins? - Page 1
Forum section: electronics / projects

author: gmc
author_rank: Regular Contributor
timestamp: February 28, 2020, 10:13:07 pm
content: I've got a project I'm working on and about to go get some PCB's made up.It consists of a AtMega34u2 connected to a MAX3421E using SPI bus. Once all the components are soldered onto the PCB I need to program a bootloader on the atmega using the SPI inteface.What is the correct way to share the SPI pins between the programmer (USBTiny) and the other components. I've read a few posts where it ranged from using 330R resistors on the SCK/MOSIO lines, or only needing a pullup resistor on the SS lines.I've attached a schematic for my project. The atmega32u is connected to the max3421e using level shifters. Do I need to be concerned with using inline resistors? Or can I just program the chip by connecting the usbtiny to the spi bus.I would to fix any possible issues before any prototype pcb's are made up.

author: thm_w
author_rank: Super Contributor
timestamp: February 29, 2020, 01:11:59 am
content: See here:https://www.avrfreaks.net/forum/isp-spi-resistorsI think the current schematic might be OK as is, as you have the level translators and L_SS is pulled up via a resistor. So the SPI slave (max3421) should not be able to interfere with the programming lines. Debugging might be a different story, but you could use debugwire instead (uses reset line).Generic recommendations:- I would consider connecting the INT pin on the MAX3421 unless you are sure its not needed.- Add a bit of bulk capacitance on the 3.3V rail, it looks like only 100nF is present.- Check that MISO level translator is working as you expect, since signal is coming from the slave, to the master, not from master to slave as SCK/SS/MOSI are.

author: gmc
author_rank: Regular Contributor
timestamp: February 29, 2020, 09:51:13 am
content: Thanks for the tips. Good spot on the cap for the 3v3 rail. I'll get some prototype pcb's done and see how it goes.The level shifter is working on the MISO line. I've got the MAX3421E hooked up to an Arduino via a level shifter and don't have any issues.
Atmega32xx PCB footprints - Page 1
Forum section: electronics / projects

author: regimon
author_rank: Newbie
timestamp: January 28, 2015, 03:50:33 pm
content: Quick question but finding it difficult to get a definite answer; Are the footprints/ schematics the same for the atmega32u4 and the atmega32UC3B?I'm wanting to build a design based on the atmega32U4 but can only find the OrCAD libraries for the atmega32UC3B. Does anyone have experience with the atmega32U4 or have an alternative footprint/ schematic that is identical.Cheers, Reg.

author: ajb
author_rank: Super Contributor
timestamp: January 28, 2015, 06:42:15 pm
content: I don't think there's any such thing as an ATMega32UC3B. There's an AT32UC3B, but that's a 32-bit UC3, not an 8-bit AVR, let alone an ATMega. If that's what you're talking about then the pinouts will certainly be different--they don't even have the same pin count!Generally with AVRs the first number at the end indicates the flash memory size--so an ATMega32u4 should be the same as an ATMega16u4 except the former will have twice as much flash (and usually twice as much SRAM and EEPROM) as the latter. Check the datasheets to be sure, though!

author: regimon
author_rank: Newbie
timestamp: January 29, 2015, 01:54:59 pm
content: Yes sorry I was indeed referring to the AT32UC3B. Seem to have found the correct footprint on SnapEDA anyway.Thanks for your help ajb
aTmega8 or 16 joystick for PC - Page 1
Forum section: electronics / projects

author: Saulius
author_rank: Newbie
timestamp: January 16, 2015, 11:04:15 am
content: HelloI am a fan of racing games. And I was looking for keyboard with pressure sensitive arrow keys, but I couldn’t find one to buy, so I decided to make those keys with potentiometers, like two axes USB joystick. But the problem is I am quite green in electronics. Therefore I want to ask You how would You be doing about the electronic part of this project. I have aTmega8 and aTmega16 lying around, so I thought I use them to communicate with PC via USB. So if you had similar project, maybe You could link me to some schematics and code for avr mc.P. S. I have Logitech G27 racing wheel, but I like arrows better, but I want them to be pressures sensitiveThanx

author: Stonent
author_rank: Super Contributor
timestamp: January 16, 2015, 04:05:46 pm
content: PlayStation 2 controllers have pressure sensitive buttons. I assume PlayStation 3 controllers do as well.According to howstuffworks.com they do it like this:http://electronics.howstuffworks.com/ps23.htmQuoteI think the PS3 has a USB connection that can connect it to a PC, the PS2 would need an adapter.You could possibly use the ATMega8 or 16 for an interface using the V-USB library. Since they do not natively support USB, you'd be doing it all in software.

author: LaserSteve
author_rank: Super Contributor
timestamp: January 17, 2015, 02:36:24 am
content: For a Mega without built in USB Google MJOY16. Be aware it does not always enumerate correctly with all computers. When that occurs you need an external hub.Or just buy a better ATMEGA with the built in USB hardware.Steve
ATMEL ATF16V8CZ - Page 1
Forum section: electronics / projects

author: TBone1946
author_rank: Newbie
timestamp: July 14, 2023, 09:05:40 pm
content: I have the board that is shown in the attachment. (3PH PWM Brushless DC (BLDC)Motor Controller 2.jpg) It is made to drive a 24 volt DC three phase BLDC motor. The power terminals are noted. (POW) I have a 24 volt DC supply. There are 5 control terminals for the controller. (Blue terminal block) The added lines on the board show the second layer connections that are made on the bottom of the board. I see the two connections that are made to the ATMEL ATF16V8CZ from the terminal block. The controller drives the motor from a slow speed to a top speed in both the forward and the reverse directions using the two external terminals. I assume that a PWM signal is used on one of the two terminals leading to the ATMEL but I am not sure which one and I do not know how the direction determined? Any help is greatly appreciated. The project I have is to use the worm gear driven motor for a small elevator. Thank you in advance for any advice.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: July 15, 2023, 05:29:39 am
content: The ATF16V8 is a SPLD, so can have any simply logic programmed, and the clock is on a fixed pin, so you can work back from that.Drive it with clean clock pulses, and another pin is likely direction.

author: DavidAlfa
author_rank: Super Contributor
timestamp: July 15, 2023, 08:43:03 am
content: Why did you create another thread with the same thing again?https://www.eevblog.com/forum/projects/3-ph-pwm-bldc-motor-control-board/
Atmel Employees Sue, Protest Microchip - Page 1
Forum section: electronics / projects

author: diyaudio
author_rank: Frequent Contributor
timestamp: June 23, 2016, 04:45:48 pm
content: http://www.eetimes.com/document.asp?doc_id=1329971&_mc=NL_EET_EDT_EET_daily_20160623&cid=NL_EET_EDT_EET_daily_20160623&elqTrackId=9cf9d74d5eb64c35a3e93b4db8bd980c&elq=21637fa9e943496c82f022c71af43fe0&elqaid=32803&elqat=1&elqCampaignId=28652

author: uncle_bob
author_rank: Unknown
timestamp: June 23, 2016, 09:25:45 pm
content: HiOut of the giant bundle of locations and people that all got tossed together, They are talking about some very small numbers. If you expected the "old Atmel" to win out after the acquisition, you were dreaming. That's just not the way it works.Bob

author: Neganur
author_rank: Unknown
timestamp: June 23, 2016, 10:25:42 pm
content: QuoteThey sure like selling their products in high-cost regions though.

author: uncle_bob
author_rank: Unknown
timestamp: June 23, 2016, 10:39:47 pm
content: Quote from: Neganur on June 23, 2016, 10:25:42 pmHiThe shareholders of the company would expect nothing less ....Thus the "big guy" has an incentive plan to cut costs and raise prices. He makes his bonus and all is well.Bob
Atmel ICE cable stupidity - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: September 15, 2020, 03:14:53 pm
content: This is apparently well known elsewhere, but I thought that I might mention it.I've had an Atmel ICE programmer for a while.I thought that I might pick up a few spare 6" 10 pin 50 mil IDC cables since they are pretty small and get some wear and tear.The generic cables arrived (correctly made) and didn't work.It turns out that Atmel doesn't make their cables 1 to 1.So if you need a replacement cable, get a "special" Atmel one.

author: Gibson486
author_rank: Frequent Contributor
timestamp: September 15, 2020, 06:43:29 pm
content: Quote from: Renate on September 15, 2020, 03:14:53 pmIt's all about AVRdude!
Atmel u2008b ic - Page 1
Forum section: electronics / projects

author: gatoazul
author_rank: Contributor
timestamp: December 01, 2016, 11:08:09 am
content: hI,I need an Atmel /TFK U2008B IC for a speed control application.Anyone Knows where can i Buy this ics from a reputable source, even in Ebay.I bought two from Polida2008 and they dont work as expected , and probably where fakes or where salvaged parts with defects.Anyone has photos of the original markings of this ics(From Telefunken/Tfk) to compare?Thanks