hybridfree/eevblog-posts huggingface dataset:
USB Type E Key-A Connector Manufacturer Search (...again) - Page 1
Forum section: electronics / projects

author: zaan
author_rank: Newbie
timestamp: October 24, 2022, 04:16:09 pm
content: I am searching the manufacturer for a specific USB connector called USB Key-A (official name) or USB Type E (unofficial name).It is an Internal USB 3.2 (Gen2) Type C, 20 pin connector.Part of the question was answered here:https://www.eevblog.com/forum/projects/where-to-get-a-usb-3-1-type-e-front-panel-header/The female part of the connector was searched here.Now, I need the male part for it as I want a cable manufacturer to create our own cable for it. The specs are mentioned in the USB spec:https://www.usb.org/sites/default/files/USB3p1_Front_Panel_CabCon_Implment_Doc_Rev1p1.pdf#page=10(Page 10, "Figure 2-5: Reference Design of Key-A 20-Pin Cable Plug Interface Dimensions")I attached a picture of the needed connector. So, there are manufacturers for it, but I can´t find them.
USB Typet-C Orientation Detection for Power Delivery - Page 1
Forum section: electronics / projects

author: AJollet
author_rank: Newbie
timestamp: October 19, 2017, 03:47:08 pm
content: Hey everyone,I'm basically trying to make a USB rechargeable device that will be charged through a Type-C connector (purely for ease of use) and possibly by a Type-C hub on the host side.From what I gathered so far, the power lines are purely symmetrical on the connector so they're not a problem.I also read that the CC pins are used for cable orientation detection to allow proper routing of the different differential signals.I for battery charging purposes I don't really care about that but I was wondering if a Type-C hub needed to detect cable orientation in order to supply power to the device.To put it in more simple words, can I just leave all pins but the power pins floating on the device side and expect any power to be delivered ?

author: Dave
author_rank: Super Contributor
timestamp: October 19, 2017, 04:18:52 pm
content: It depends on the host, but as far as I'm aware, you need the device to be enumerated to get the host to provide power. You're going to need some sort of chip that tells the host: "Hey, I need this much power, feed me!"

author: HKJ
author_rank: Super Contributor
timestamp: October 19, 2017, 05:30:51 pm
content: Quote from: AJollet on October 19, 2017, 03:47:08 pmNo, you need a resistor to say you are a downstream device.Technically this gives you access to lowest power level and by checking the voltage at the resistor you can see if you can draw more power.You can also look for the usual usb data bus codes.

author: lucazader
author_rank: Regular Contributor
timestamp: October 20, 2017, 07:52:30 am
content: Yea all you need is a pull down resistor on on of the two CC lines.For default usb power (5v 500/900ma) it is a 5.1k pulldown resistor.I am not sure what the values for the following are, but they are also available power options, using resistors.5V 1.5A5V 3AIn testing I have found that most USB wall chargers dont need the resistors to provide power, howver most properly implemented ports do need one of these resistors to start providing power.For any power levels over 5v or over 3A, you would need to get a Power Delivery chip than can communicate with the power provider to negotiate the higher power levels.

author: HKJ
author_rank: Super Contributor
timestamp: October 20, 2017, 02:31:36 pm
content: Quote from: lucazader on October 20, 2017, 07:52:30 amIt is the power supply that need different resistor, depending on the power level. You check the voltage across the pulldown resistor to see what resistor is in the power supply.Quote from: lucazader on October 20, 2017, 07:52:30 amNot always, today you will often find QuickCharge (or other usb protocol) on usb-c chargers or usb charger with conversion cable.
USB UART and charging chipset - Page 1
Forum section: electronics / projects

author: rexxar
author_rank: Frequent Contributor
timestamp: September 13, 2018, 02:28:26 pm
content: Hi all, I'm having a pretty frustrating time trying to find the best solution for a project I'm working on. It's a lighting gizmo that runs on Li-ion cells, and needs UART over serial (it's running arduino core because I'm a lazy programmer). I need some combination of chips that provides the following:UART over serial, preferably using built in Windows drivers (likely FTDI brand)USB charge port detection, to support fast chargingI2C communication for setting charge current and reading back status (no free GPIO pins)Right now I'm using a TI BQ24257 for charging, and a Cypress CY7C65213 for UART. Both parts are expensive, and both include charge port detection. However, the TI part won't function unless the USB pins are connected, and the Cypress part requires two GPIO to read the current capacity of the port (and it only tells me 500mA or 1500mA). Plus Windows doesn't include drivers for the Cypress part, and I have to bundle that with my software, which isn't a killer, but I'd like to avoid it if I can.Any advice is appreciated. So far I've just been flicking through the Mouser catalogue trying to find suitable parts, so if there's a better way, for the love of god let me know about it
USB2.0 cable requirements - Page 1
Forum section: electronics / projects

author: IconicPCB
author_rank: Super Contributor
timestamp: December 05, 2019, 10:34:55 pm
content: A USB 2.0 camera is located on a robotic arm. It is connected to a USB port via a non standard ( highly flexible ) USB cable due to continuous movement of the arm.In general are there specific electrical requirements the USB cable has to meet ( say pF/unit length between conductors, nH/ unit length etc )

author: IconicPCB
author_rank: Super Contributor
timestamp: December 05, 2019, 10:59:01 pm
content: D+ and D- form a twisted pair transmission line with differential characteristic impedance of 90 +/-15% ohm .
USBC - Page 1
Forum section: electronics / projects

author: mjordan
author_rank: Newbie
timestamp: December 18, 2024, 12:51:43 am
content: I have a product powered from a iPad (the iPad is enclosed in a case, the USBC plug on the iPad is no longer accessible from the outside of the case).Internally (of the case) I have an 8pin USBC cable from the iPads USBC port to a custom PCB. From the iPad USBC/PCB connection I wish to tap power from the iPad to power the PCB (a low current design, ~100ma)On the custom PCB I also have a female "external USBC" which I require to charge the iPad.D-/D+ is not being used. No data transfer, this is strictly power only applicationMy problem is that upon plugging in the "external USBC" into the PCB, the iPad is not charging. I believe it's because the iPad is never leaving is "source" role to become the power "consumer". I believe this is controlled with the resistors on the CC pins and I have tried to handle that, but I am missing something...Rather than post what is not working (basically 5K1 on CC and P-Channel MOSFET with the "external USBC" VBUS on the gate)... I was hoping someone could point me to an existing solution. I can't be the first person trying to tap power from a iPad, but then also charge the iPad without removing the iPad's existing USBC connection.Thanks in advance for your help.

author: fchk
author_rank: Frequent Contributor
timestamp: December 18, 2024, 02:39:46 pm
content: You will need a dual role USB-C power controller. Such as:https://www.st.com/en/interfaces-and-transceivers/stusb1600.htmlhttps://www.ti.com/lit/ds/symlink/tusb320lai.pdf

author: mjordan
author_rank: Newbie
timestamp: December 18, 2024, 03:57:47 pm
content: Thanks for your reply! I've been reading up on the TUSB320 this morning. I agree this is the way to go, but I am unsure how to use it. Do you know of any references that would help me use the TUSB320 to do something like in the image?
USB/CAN-FD Interface - Page 1
Forum section: electronics / projects

author: Rudolph Riedel
author_rank: Regular Contributor
timestamp: December 12, 2021, 08:50:48 pm
content: Hello,it is definately not a good time for open source hardware projects and probably will not be for at least annother year.But well, this has been in the making for quite some time now and I started to use it more regulary.I built a USB/CAN-FD interface with two isolated channels capable of doing up to 8MBit/s.https://github.com/RudolphRiedel/USB_CAN-FDAnd it is all open source down to the Altium Designer design files.The firmware is not by me:https://github.com/jgressmann/supercanThis is a close cooperation though.And there is a free Windows application supporting the interface as well:https://github.com/TDahlmann/canppWe three work for the same company in the automotive sector and we are using CAN++ as wellas proprietary software to test automotive control units.I do develop CAN nodes from hardware to software but these are usually tools for test-automation like specialized relay boards or prototypes for a proof-of-concept.But we also started using our interfaces in bigger projects to complement our usual tools.So, I am aware that you could not currently build your own units and I am not planning on selling any.Well, maybe you are already sitting on ATSAME51J and wonder what to do with these.Have fun, Rudolph
USBLC6-2SC6Y - which ethernet lines go where? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: January 30, 2018, 12:53:39 am
content: http://www.st.com/content/ccc/resource/technical/document/datasheet/group0/94/15/6c/58/ba/91/46/42/DM00055262/files/DM00055262.pdf/jcr:content/translations/en.DM00055262.pdfIt says it can be used for 10/100 Ethernet. The datasheet shows 1/6 connected internally and 3/4 connected internally. I am looking at someone's sch where they have TD+ on 3 and TD- on 4, RD+ on 1 and RD- on 6. Is this right? Wouldn't the internal connection short the TD+/TD- together? The datasheet didn't give an Ethernet example...

author: Phoenix
author_rank: Frequent Contributor
timestamp: January 30, 2018, 12:59:26 am
content: I'd expect you'd need of those 2 chips for ethernet. Were they using a different chip with 4 signal inputs instead?

author: wraper
author_rank: Unknown
timestamp: January 30, 2018, 01:09:58 am
content: They are meant for signal to be routed THROUGH the device. You'll need 2 of these for ethernet.Did you try to reading a few very first words in the datasheet?Quote

author: alank2
author_rank: Super Contributor
timestamp: January 30, 2018, 01:25:14 am
content: Thanks guys; I appreciate the help.

author: John Heath
author_rank: Frequent Contributor
timestamp: January 30, 2018, 02:11:19 am
content: What is TR and what is RD can be confusing. What is transmit to one unit is receive to another , it is relative. A rule of thumb to sort this out is the audio standard that came before. For whatever diagram you are looking at the label receive or transmit is always relative to the schematic you are looking at. In the case of a data cables it is both receiver and transmit. The added confusion from this led to the auto detect cross over vs standard patch cable. A switch box and most computers is smart enough to test for wrong type cable and adjust automatically. Not all laptops will do this , maybe 50/50. Does this help?

author: alank2
author_rank: Super Contributor
timestamp: January 30, 2018, 02:41:15 am
content: Thanks John - I've definitely run into RX/TX and which is input or output based on the point of view.
USB/RS485 with FTDI extra byte - Page 1
Forum section: electronics / projects

author: roymesi
author_rank: Newbie
timestamp: June 19, 2017, 10:40:57 am
content: Hi all,I've found this link:https://www.eevblog.com/forum/projects/ftdi-usb-rs485-pcb-and-cables-receive-00h-because-ftdi-has-chosen-a-crap-driver/which pretty much sums what I'm experiencing. Nevertheless, at first, I did not have bias resistors, and my controller board (using K64 of NXP) answered with alot of exception messages due to error messages coming into it. Then I've places bias resistors and things got better.I have a half duplex driver/reciever with no fail safe. I've placed bias resistors on the RS485 lines passing into it. It did managed to quiet down all the error messages, but still I receive an extra byte of "00" after each message I sent from the controller to the PC.Since my transceiver is 3.3, and my controller is 3.3, I've calculated the resistors to be of different values than 750ohm (which fit to 5v), but my DC bias is 300mv.Any idea how to solve the extra byte?The SW guys are using libmodbus library (we're using modbus protocol) so they can, theoretically, disregard this last byte, but still, I prefer not alter the libmodbus library.Interesting to say, when using this product by MOXA:https://www.moxa.com/product/CP-132UL_V2.htmeverything works well. It just costs twice as much than the USB dongle of FTDI...Thanks!

author: tatus1969
author_rank: Super Contributor
timestamp: June 19, 2017, 02:34:32 pm
content: is it possible that the bias has wrong polarity, causing BREAK condition instead of IDLE/STOP?

author: voltsandjolts
author_rank: Unknown
timestamp: June 19, 2017, 03:25:15 pm
content: I had this extra 00h byte problem on an adapter that had the RS485 driver TXEN and RXEN shorted together (as per FTDI datasheet) but I think that is part of the problem. For me the easiest fix was to have RXEN continually enabled such that the transmit bytes were echoed (not necessarily bad thing because you then know the transmit went OK) and the 00h extra byte problem disappeared. Of course your software has to be changed to allow for the transmit chars being echoed but a lot of commercial software has a tick box for that.

author: voltsandjolts
author_rank: Unknown
timestamp: June 19, 2017, 03:30:42 pm
content: Looking again it seems some FTDI schematics drive TXEN and RXEN separately, I bet they don't have the extra 00h byte (?)e.g. page 12:http://www.ftdichip.com/Support/Documents/DataSheets/Cables/DS_USB_RS485_PCB.pdf

author: roymesi
author_rank: Newbie
timestamp: June 21, 2017, 05:04:26 am
content: Ok, guys. I'll check all your ideas and update. Thank you very much.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 21, 2017, 08:36:16 am
content: Also use a scope to see what is actually hapenning on the bus
USBscope(dot)eu - Page 1
Forum section: electronics / projects

author: moby
author_rank: Contributor
timestamp: May 17, 2019, 01:55:27 am
content: Does anyone out there use a USBscope.eu scope/datalogger?. I bought one almost a decade ago to track PV panel output, battery voltage and a couple of other parameters in a test mockup of a solar installation which was going to live in a highly inaccessable place. It worked a treat and generated pretty pictures and graphs of 4 input voltages. The situation has reared its ugly head again and I need to do a repeat set of tests (different panels, batteries etc) but inexplicably my datalogger has died. There seems to be only one way of contacting USBscope.eu and that is via a dialog box on their website, and that gives server error 500. Given that their web page was last updated 2010, I suspect they may no longer exist. Does anyone know how to contact them or have a functional unit for sale?. Ideas, folks please (or am I going to have to emulate it with a Rigol 1054).Cheers, Mike

author: KaneTW
author_rank: Frequent Contributor
timestamp: May 17, 2019, 04:44:44 am
content: The company behind it is Scope2k4 B.V, according to WHOIS. It gives a contact email matthijsfh@planet.nl.
USB/VIN Switch Mechanism for Custom ESP32 Board - Page 1
Forum section: electronics / projects

author: czagrzebski
author_rank: Newbie
timestamp: April 14, 2024, 05:48:55 pm
content: Hello.I am designing a PCB for an ESP32 that features an LM2596 switching regulator to power the chip using a 7 to 12v DC input. I am also allowing the board to be powered through the USB-C port when VIN is not present. As a result, I designed a switching mechanism to toggle between VIN and VBUS to prevent power from going back onto the USB-C port when VIN is present. I have a P-Channel FET for the VBUS that is toggled off by a divider when VIN is present. However, I have a concern regarding when VIN is not plugged in and VBUS is.My main concern is the 5V from VBUS that will be present on the output of the switching regulator when VIN is not present (i.e., Vin < Vout). Will this be a problem? I have seen designs that use the AMS1117 LDO (https://learn.adafruit.com/assets/98525) that put voltage back on the output of the regulator when VIN is not present, but I was wondering if this is ok for the LM2596. Attached is the schematic of the LM2596/switching mechanism.Thanks,

author: PlainName
author_rank: Super Contributor
timestamp: April 14, 2024, 06:33:57 pm
content: Why not just post the netlist?Seriously, you have USB_PORT_D_N label right next to a USB_PORT_D_N label! Just join the things up and then you canvisuallysee that the former is joined to the latter. As it is, you have to read the damn label and then go looking for where (on the entire sheet) it might be used.Similarly, where the Vin 5V meets the USB 5V it would be more obvious what's going on if it were actually visually connected. You can still put boxes around the appropriate parts, but for pities sake joined up the dots.

author: xvr
author_rank: Frequent Contributor
timestamp: April 14, 2024, 06:44:15 pm
content: On 7V Vin your MOSFET will not be closed - after divider you got 3.5V that less, than 5V of VBUS. MOSFET got 1.5V on gate and will be  open.Why not just put 2 diodes and ored both power source?

author: fchk
author_rank: Frequent Contributor
timestamp: April 14, 2024, 06:47:09 pm
content: This problem calls for an ideal diode. Ideal diodes have got only very small forward voltages.This would solve your problem:https://www.analog.com/media/en/technical-documentation/data-sheets/4413fd.pdffchk
uSD card with STM32 - Page 1
Forum section: electronics / projects

author: spanacc
author_rank: Newbie
timestamp: January 04, 2018, 05:43:47 am
content: Hi guys,I have a problem while trying to access a Sandisk uSD HC card using a STM32 micro in SPI mode.I have everything wired up correctly, I am using 250Kbps SPI speed, I have pull-ups set and still my card won't return anything else except 0xFFI am sending more than 80 clocks with FF on MOSI and CS high, I am sending a proper idle command with a valid CRC : 0x40, 0, 0, 0, 0, 0x95I only get 0xFF back.I attached a SUMP capture for reference.Have you encountered something like this before ?

author: thm_w
author_rank: Super Contributor
timestamp: January 05, 2018, 01:16:38 am
content: Have you tried a number of cards? Try an older 2GB or 4GB card, see if any work.Is there any way you can display a waveform capture instead of a table?http://www.chlazza.net/imgs/SDcardInitFlowchart_3.01.pngbtw which STM32 out of curiousity
uSD too bulky, what other storage is there? - Page 1
Forum section: electronics / projects

author: cdwijs
author_rank: Regular Contributor
timestamp: April 09, 2016, 04:13:34 pm
content: Hi All,I would like to build a very small datalogger. So small in fact, that I'm looking for something that can hold some (megabytes of) data, but is smaller than an uSD card.I have found a chip that's 5x6mm, but I would like to know what other options are out there:http://nl.farnell.com/spansion/s25fl164k0xnfi011/ic-memory-flash-64mbit-wson-8/dp/2363324Kind regards,Cedric

author: exmadscientist
author_rank: Frequent Contributor
timestamp: April 09, 2016, 05:07:55 pm
content: What are your requirements (both minimum and goal)? Size and preferred interface are both important.There are plenty of truly tiny memories out there, some even below 1 mm². But the really small ones can't store much: there's both a die size limitation and a minimum pin count for the interfaces on the larger (parallel) memories.The 5 mm×6 mm size serial flashes are quite common, with options from many manufacturers. There are also several available in 2 mm×3 mm, but the selection there does decrease.

author: ajb
author_rank: Super Contributor
timestamp: April 09, 2016, 05:54:11 pm
content: Note that with the larger serial memories, the minimum erasable size may get to be a bit large (4kbyte in the one you linked), so if you want to do a circular log (write until full, then start overwriting the oldest data) you will need to either give up an entire sector of data at a time or be able to hold a 4kB (or whatever) buffer in your MCU's memory before writing to the external memory.
use a 74595 as a 74164? - Page 1
Forum section: electronics / projects

author: ralphd
author_rank: Frequent Contributor
timestamp: September 14, 2015, 03:35:22 am
content: I'm looking to use a 74HC595 in a circuit instead of a 164. Keeping OE low is the easy part. To delay STCP, I'm thinking of putting a 2.2K resistor in series from SHCP. I figure with about 10pf of input capacitance the pulse will be delayed more than the 15ns setup time specified in the datasheet.Should this work?

author: eetech00
author_rank: Regular Contributor
timestamp: September 14, 2015, 02:23:35 pm
content: Post your circuit.
Use a 74HC595 as a 164 - Page 1
Forum section: electronics / projects

author: ralphd
author_rank: Frequent Contributor
timestamp: October 27, 2015, 07:00:15 pm
content: Building a circuit that calls for a 74164 but you only have 595s in your parts bin? Just connect RCLK to SRCLK with a 10K resistor.http://nerdralph.blogspot.ca/2015/10/using-74hc595-as-74hc164-shift-register.html
use battery charger IC MAX1811 with dc wall adapter - Page 1
Forum section: electronics / projects

author: alexscep
author_rank: Contributor
timestamp: May 31, 2015, 01:57:42 pm
content: Dear forum-members,i was wondering if i could use the MAX1811 lithium-polymer charger ic with a simple dc wall adapter instead of powering it through USB wall adapter with micro-sd connection. Is there a difference between these two kinds of wall adapters or is it just a matter of connection? And if i use a regular dc wall adapter, shouldn't i include a 5 volt regulator? Or would this be unnecessary?

author: Christopher
author_rank: Frequent Contributor
timestamp: May 31, 2015, 05:33:00 pm
content: The first line of the datasheet goes something like this:QuoteSo you have to regulate the input uing a buck converter or linear regulator if the power is small enough (doubtful) to less than 6.5V, personally would recommend 5V to no piss away excess heat in the battery charger chip.--You can get switching regulator battery charger ICs from both maxim and linear, i've used the latter in the past. This increases the overall efficiency and will probably reduce cost & increase ease of implementation
Use BLE to configure Dual-band WiFi Microcontroller - Page 1
Forum section: electronics / projects

author: dakamaster
author_rank: Newbie
timestamp: May 28, 2021, 10:40:46 am
content: Here we introduce another way to download firmware to your microcontroller board.With a BLE5.0 & Dual-band WiFi microcontroller, you will never have to worry about re-compiling the code just to change the WiFi SSID and password.The working principle of BLE5.0 is working as follows:1. the Ameba RTL8722DM board will send BLE information to your phone;2. the phone will send the corresponding WiFi configuration including SSID and password to the RTL8722DM board;3. the board is able to connect to the WiFi with the same SSID as your phone;Please follow our GitHub: "ambiot" for more information and the most updated features:https://github.com/ambiot.YouTube demo video for you to enhance the understanding:
USE GPSDO 10 MHz to make super accurate DDS siggen? - Page 1
Forum section: electronics / projects

author: cdev
author_rank: Super Contributor
timestamp: August 16, 2017, 08:52:25 pm
content: The HackRF one seems to implement something like this internally with its DDS clock generation. This seems like one of the most useful things that can be done with a GPSDO.Has anybody implemented this and if so, how was it done. How did you control it?

author: Rerouter
author_rank: Super Contributor
timestamp: August 17, 2017, 03:00:49 am
content: Find a DDS with a frequency in, hook it up to a GPSDO 10Mhz output, and away you go, be aware that because of the constant tuning of the oscillator there can be some jitter introduced, vs a rubidium Oscialltor, where its stable, but not garenteed to be exactly 10Mhz

author: cdev
author_rank: Super Contributor
timestamp: August 17, 2017, 03:29:42 am
content: Which DDS would you recommend?

author: DaJMasta
author_rank: Super Contributor
timestamp: August 17, 2017, 04:31:35 am
content: If you're looking to make your own, there's a number of standards from Analog Devices and a few projects on the forum that have used them. In a commercial function gen, you'd have the 10MHz input be a reference for the internal oscillator PLL, but if you selected the frequency right, you could always just clock the DDS chip directly from the oscillator input.A basic DDS generator is not going to be too hard to build up (and you can get some cheap on ebay as single boards with a screen), but as the speed increases you run into more and more issues with layout and parasitics. Selecting the right output amp is also very important if you want more than a basic TTL range or similar, since typically function generators that can be hooked up to various things need a decent amount of drive current available.

author: DimitriP
author_rank: Super Contributor
timestamp: August 17, 2017, 05:27:21 am
content: W3PM GPS referenced DDS VFOhttp://www.knology.net/~gmarcus/VFO/GPS_Sig_Gen_v1_1.pdfhttp://www.knology.net/~gmarcus/VFO/Enjoy!

author: bingo600
author_rank: Super Contributor
timestamp: August 17, 2017, 08:41:04 pm
content: Quote from: DimitriP on August 17, 2017, 05:27:21 amI'd get a AD9851 Module instead , has an internal 6x clock multiplier.Making it usefull to 60MHz w. 10MHz in./Bingo
using the LT3081's ILIM pin in current-source mode - Page 1
Forum section: electronics / projects

author: RustyShackleford
author_rank: Regular Contributor
timestamp: April 07, 2018, 09:01:03 pm
content: I'm building an LT3081-based digitally-adjustable current source (as described in OP ofhttps://www.eevblog.com/forum/projects/digitally-adjustable-lt3081-based-current-source/msg1338751/#msg1338751). In the circuit, the potentiometer attached to SET is actually an MCP4162 digital pot, controlled using SPI interface from an Arduino. And the load is a series connected string of up to 10 LEDs.Modifying the circuit in that post (see attached), I'd like to use a 2K resistor between ILIM and OUT (as shown in the data sheet) to limit the current to 500ma or so. But they are pretty cagey about whether it's ok to use the ILIM pin when configured as a current source; p.13, see link below: "In a current source configuration, programmable current limit and current monitoring functions are often unused. When not used, tie IMON to OUT and leave ILIM open. The TEMP pin is still available for use...". But it seems a perfectly reasonable thing to want to do - for example, if the SET pin becomes open, its voltage could rise high enough to cause the current source to provide more current than one's application might tolerate.Also, it occurred to me that by shorting ILIM to OUT, with a FET or some other simple way, I could implement an "enable" function for the circuit. When enableBar is high, the FET shorts ILIM to OUT and the LT3081 sources no current. Does this seem reasonable ? I see nothing in the data sheet that forbids shorting ILIM to OUT: p.11 states "Shorting this resistor out disables all output current to the load, only bias currents remain". The nFET might not be the best way to accomplish the shorting function though.The data sheet for the LT3081 is at:http://www.analog.com/media/en/technical-documentation/data-sheets/3081fc.pdf
Use Macbook retina screen as a monitor? - Page 1
Forum section: electronics / projects

author: lufihengr
author_rank: Contributor
timestamp: March 19, 2014, 06:32:42 pm
content: So my idea was inspired by OSCAR (the open source iPad display adapter thing) and I was wondering if a Macbook Pro retina display interfaces the same way as an iPad one? I had a look at a bare display and the connector looked pretty different, but could it still be eDisplayport? If so, maybe oscar could be modified to use an even higher res Mac retina display?Or maybe a whole new adapter needs to be designed. I hope someone would have some info on this, as I would love to have a 3 screen setup with my mac, and why not even with my gaming PC! High res displays for cheap sounds like a good deal to me.PS. I hope this is not in the wrong place since I am new here, I apologise if this is misplaced.

author: amyk
author_rank: Super Contributor
timestamp: March 19, 2014, 07:37:57 pm
content: Which Macbook Pro, exactly?AFAIR from reading schematics most of them used LVDS.

author: lufihengr
author_rank: Contributor
timestamp: March 19, 2014, 07:41:48 pm
content: Quote from: amyk on March 19, 2014, 07:37:57 pmWell I have a late 2013 13 inch Macbook Pro.Edit: You seem to be right about the interface being LVDS. So I need a LVDS to thunderbolt/displayport or hdmi adapter... I wonder if it's possible.

author: amyk
author_rank: Super Contributor
timestamp: March 19, 2014, 10:00:11 pm
content: You can find one of those inside any LCD monitor (ones with cracked panels are a good candidate)... although the scaler will probably need to be reprogrammed to fit the timing and resolution of the panel. (As a bonus, you get the OSD controls for free.)There are also some companies thatmake these boards specifically, although it'll probably cost you a bit.

author: daedalus
author_rank: Regular Contributor
timestamp: March 19, 2014, 11:00:22 pm
content: I was under the impression all the retina panels are eDP, and as such should require a cable adapter and possibly a backlight driver / power supply. Heres a page that might be of interesthttp://mikesmods.com/mm-wp/?p=212edit: heres a finished one:http://dp2mbpr.rozsnyo.com/

author: lufihengr
author_rank: Contributor
timestamp: March 20, 2014, 02:24:32 pm
content: Wow, thanks for the replies! I will have to find one of these controllers for as cheap as I can get. 149$ for the controller + the screen + shipping will be quite a lot.I wonder if oscar can be manipulated to drive one of these mac displays?
use of coupled inductors in CÛK (inverting) DC/DC Converter possible? - Page 1
Forum section: electronics / projects

author: Andree Henkel
author_rank: Regular Contributor
timestamp: January 04, 2023, 11:50:31 am
content: I want to use a CÛK topology to create an inverted voltage.So clear is I need two inductors.With sepic topology I know it is possible to either use 2 single inductors, or a double coupled one.but how is it with CÛK topology? I would prefer to use a double coupled one in a toroid configuration to avoid stray magnetic fields, but does that work?

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 04, 2023, 01:55:20 pm
content: Coupled inductor will work just fine. In fact, it will work better than separate inductors. Note that SEPIC and Cuk are basically the same, only difference is the way the output is connected.

author: Picuino
author_rank: Super Contributor
timestamp: January 04, 2023, 01:58:23 pm
content: With coupled inductors you can get the output current to be almost constant, just like with SEPIC.Edit:Benefits of the Coupled Inductors Combined Cuk-SEPIC (CI-CCS) Converterhttps://core.ac.uk/download/pdf/162912855.pdf

author: Andree Henkel
author_rank: Regular Contributor
timestamp: January 06, 2023, 09:12:33 am
content: what about the dot markers of the two inductors?my guess is they should both either be on left side in drawing or both on right side of inductor, but should not be on oposite sides.Is this correct?

author: Picuino
author_rank: Super Contributor
timestamp: January 06, 2023, 05:48:42 pm
content: Attached image.

author: minifloat
author_rank: Contributor
timestamp: January 08, 2023, 08:47:04 am
content: Quote from: Picuino on January 06, 2023, 05:48:42 pmC2 will go BANG because wrong polaritybr mf
Use of twisted pairs with fundamentally single-ended DUT - Page 1
Forum section: electronics / projects

author: ezalys
author_rank: Frequent Contributor
timestamp: August 25, 2020, 05:34:49 am
content: Let's suppose I'm interested in measuring the voltage response of a DUT to some imposed voltages. The DUT takes V1, V2, V3 as inputs relative to some GND, and outputs V4 relative to the same GND. All signals are below 100 kHz, and there's a 4 m run of wire. Is there any benefit in using four twisted pairs (V1, GND), (V2, GND), (V3, GND), (V4, GND), where for each twisted pair, one of the leads is bonded to ground, and the twisted pair is either stimulated (in the case of an input) or sensed (in the case of an output) by a differential circuit. The DUT can not be extended with differential drivers (it will be deep inside a cryostat at 300 millikelvin.)

author: Berni
author_rank: Super Contributor
timestamp: August 25, 2020, 06:22:01 am
content: It depends.If the voltages in question are very small then having separate twisted wires for each might be a lot of help. This avoids voltage drops in the ground wire causing offsets, minimizes the chance of accidental thermocouple voltages along the way (They still happen but are close together where the cable is connected as a pair) and reduces the magnetic loop area so that the cable is less likely to pick up noise.With large clear signals you are probably fine at 100KHz using just normal cables as long as they are sensibly routed. But Using twisted pair never hurts.

author: KT88
author_rank: Frequent Contributor
timestamp: August 25, 2020, 06:46:41 pm
content: Idividual twisted pair connections will very likely improve the signal integrity for two reasons:1. Having AC signals makes the Impedance of the signal return (aka GND) more relevant. It will be higher than just the resistance. Even the weakest signal will have some influence on this return lead no matter how massive it is. Sharing this return with another signal would superimpose these return signals from different channels.2. Different impedances of signal- and return path would cause mode conversion: Common mode iterferences will cause different voltage drops for the signal- and return leads.The remedy for these effects is in fact using individual twisted pairs. It doesn't matter (a lot) if the signals are fully differential or single ended. You only need a (very) good instrumentation amp (or in case of AC only a tranformer) to receive the difference while suppressing common mode noise. Connecting the returns at the receive side is a nono b.t.w.... In case of strong interferences a shielded twisted pair would be a further improvement.
Use Parallax 2X16 Display Driver with 4X20 Display? - Page 1
Forum section: electronics / projects

author: jpanhalt
author_rank: Super Contributor
timestamp: February 21, 2018, 05:20:08 am
content: Does anyone know whether the display driver board for a 2X16 Parallax display will work with a 4x20 display? By work, I mean give a 4X20 display.Both boards from Parallax seem to be identical, have an Atmega MEGA48PA chip, and the display controllers are apparently Hitachi HD44780 or compatible.John

author: ZomBiE80
author_rank: Contributor
timestamp: February 21, 2018, 10:42:25 am
content: Should work. At the beginning of libraries should be initialisation lines stating lcd config. eg. 16.2 etc.
Use Two digital pots in 1 IC at different voltages - Page 1
Forum section: electronics / projects

author: Willemg12
author_rank: Newbie
timestamp: August 02, 2017, 05:05:32 pm
content: To do a modernization of an old lab supply I want to replace the old pots with digital potentiometers.TI and Linear Technology have good choices in that.I want to steer these over SPI/I2C. The problem I face is that the digital potentiometer ICs cannot be used out of the rail to rail voltages. E.g. 0V-5VWhere I want to be one at the GND and the other at the VCC level. +24VUPDATE. In the figure a schematic is shown with the two pots in.So as this is out of spec for most ICswhat could be a solution for this?Thank you

author: Benta
author_rank: Super Contributor
timestamp: August 02, 2017, 05:15:27 pm
content: I'd check ON Semiconductor. ON acquired Catalyst, who were famous for their digital pots.

author: Willemg12
author_rank: Newbie
timestamp: August 02, 2017, 06:54:41 pm
content: I did. ON has a pot that has Vh up to 16 V.But in my case that will be not enough, as i work with 24 volts.Should i use extra Elements..Dunno...

author: tszaboo
author_rank: Super Contributor
timestamp: August 02, 2017, 07:04:11 pm
content: Some AD parts, like AD7376 goes up to 30V. They dont work outside the suply rails, because they have FETs built in, switching stuff.

author: Howardlong
author_rank: Super Contributor
timestamp: August 02, 2017, 09:33:37 pm
content: Microchip MCP41HV31/51 for SPI, MCP45HV31/51 for I2C, but they are only single pot per package. Up to 36V, or +/-18V.

author: Zero999
author_rank: Super Contributor
timestamp: August 02, 2017, 10:11:45 pm
content: The schematics don't look right. Are they direct extracts from the service manual or the product of reverse engineering?Is it not possible to use a DAC and suitable amplifier? Normally the voltage and current limits are controlled by a reference which is set by potentiometers. You can probably replace the potentiometers with voltage sources.

author: Willemg12
author_rank: Newbie
timestamp: August 03, 2017, 08:39:26 pm
content: Thanks hero999 and all othersYou were right. At first the only thing that i wanted was a direct change from analog to digital.I included the schematic of my trustworthy old bench supply.The pot P2 is easily interchangable (though i not favor the value of 1k) But what about P1....Geven the fact that i want one uP control the device ...

author: Benta
author_rank: Super Contributor
timestamp: August 03, 2017, 09:34:44 pm
content: Something's still wrong... the power stage has no base drive.Scratch that, I just untangled the 723 ground connection.
Use USB PD capable power sources as custom power supply - Page 1
Forum section: electronics / projects

author: itami
author_rank: Newbie
timestamp: July 11, 2019, 07:55:08 pm
content: Hello,I need to draw 15V from USB C Power Delivery capable devices such as power banks or chargers.So I need a rather small tool or build which will send the request for 15V to the power supplying device.This tool or build should be built to last and work with around 40W during long periods of time as I'm building a portable special lamp.Thank you so much for your help!

author: TimNJ
author_rank: Super Contributor
timestamp: July 12, 2019, 04:21:22 am
content: I've been getting into the nitty gritty with USB PD for the last week or so (at work).Tis quite a mess indeed. Not terrible once you've spent 50 hours reading the specs and supporting documents, but pretty confusing if you haven't.Are you looking for an IC?I noticed this one recently: STUSB4500https://www.st.com/en/interfaces-and-transceivers/stusb4500.htmlSeems pretty straightforward to use/implement if QFN package is okay for you. (Note: Most of the PD stuff is QFN or chip-scale because USB PD finds most of its use on highly integrated systems like smartphones, computers, etc.)

author: viperidae
author_rank: Frequent Contributor
timestamp: July 12, 2019, 05:13:47 am
content: I heard you can save half a cent off your bom if you combine the CC1 and CC2 resistors...

author: ptricks
author_rank: Frequent Contributor
timestamp: July 12, 2019, 11:17:39 am
content: Quote from: viperidae on July 12, 2019, 05:13:47 amRaspberry Pi4

author: LapTop006
author_rank: Unknown
timestamp: July 14, 2019, 07:58:51 am
content: The PD buddy sinkshould at least get you started.Any current rev PD supply that outputs at least 30W should have a 15v output if negotiated.
Use xtal or oscillator module? - Page 1
Forum section: electronics / projects

author: Circlotron
author_rank: Super Contributor
timestamp: November 08, 2014, 01:13:30 pm
content: I'm updating an old board. It uses three 'HC908 micros that all run at the same frequency. In the older version I had an 8MHz crystal on the first one then a 22pF cap coupling to the next osc input and the same to the third. 10M resistor across each set of osc pins. Now I'm thinking if I use an oscillator module that has a full rail-to-rail square wave output rather than a more or less sinewave from the crystal oscillators I could ditch the extra 22pF caps and 10M resistors and just connect each OSC output directly to the next OSC input.Are there any other good reasons for using an oscillator module instead of a crystal? Stability is not an issue. Having 4 mounting pins seems good because it is for an automotive environment.

author: dannyf
author_rank: Super Contributor
timestamp: November 08, 2014, 02:29:59 pm
content: You can save the capacitors and resistors without using external oscillators.

author: Kjelt
author_rank: Super Contributor
timestamp: November 08, 2014, 04:29:52 pm
content: Quote from: Circlotron on November 08, 2014, 01:13:30 pmAFAIK correct me if i am wrong : you have a Guaranteed startup, less prone to be influenced from outside signals, but since it is a square wave it is a bit worse for other signals (EMC).
Uses for a broken Tablet - Page 1
Forum section: electronics / projects

author: Richard1972
author_rank: Contributor
timestamp: November 08, 2019, 09:08:15 pm
content: Hi everyone, this is my first post so apologies if it’s in the wrong forum. I just wanted to ask if anyone has found any interesting uses for an old broken tablet. I have a Lenovo 10inch one that has a broken lcd. I don’t really want to replace the screen so I just wondered if anyone has any cool ideas of what can be done with it? Should I maybe just salvage parts or stick it on flea bay for spares? Any ideas will be much appreciated.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 09, 2019, 12:00:34 am
content: You could try crypto mining with it, although that's nowhere as profitable as it was in the past. At this point, the only coin (that I'm aware of) still worth mining on a tablet is Swagbucks.

author: Renate
author_rank: Super Contributor
timestamp: November 09, 2019, 01:31:11 am
content: Broken screen? Try adbgrab.exe (google it).It will allow you to view the screen and click on it.(This is all presuming that you had ADB enabled on it already. It's a bit trickier if you haven't.)Ok, it's not rocket science, but at least it will allow you to play with it and maybe get some ideas.

author: Matty
author_rank: Contributor
timestamp: November 09, 2019, 10:18:44 am
content: You could use it as a security camera. Point the camera though the peep hole of the door. So you don't need move from your main computer to see who is at the door?.Connect the power button to the door bell (not directly) to bring it out of standby a little quicker.Silly idea but heck.. I thought I'll mention it.

author: m3vuv
author_rank: Super Contributor
timestamp: November 09, 2019, 08:29:39 pm
content: door stop?

author: Richard1972
author_rank: Contributor
timestamp: November 13, 2019, 11:57:27 pm
content: Thank you for your ideas. Might just hold onto it for a while and see if anymore come in that need parts.

author: rvalente
author_rank: Frequent Contributor
timestamp: November 14, 2019, 09:54:51 am
content: Add a usb otg cable and use it as usb battery.
Uses for cell phone screens - Page 1
Forum section: electronics / projects

author: jrevard
author_rank: Newbie
timestamp: December 11, 2015, 07:59:44 am
content: Hey all, I have old phones (e.g.Samsung Note 3) and am looking for ideas to put them to use. I am fairly technical but am a beginner considering my audience. I thought the screen would be neat to build a project around, but then was thinking even with the best case scenario with hardware there may be some software nightmares (not sure about any of that).Has anyone done anything cool with old phones?Thanks!!

author: l0rd_hex
author_rank: Regular Contributor
timestamp: December 11, 2015, 08:20:20 am
content: Perhaps a networked music player (hooked up to AUX in on your jambox. Or maybe a slimmed down "camera" only Android bud for a handy wireless camera?I have an old Samsung Galaxy lying around too, I've thought of both but haven't done either project

author: amyk
author_rank: Super Contributor
timestamp: December 11, 2015, 10:35:17 am
content: I thought you were referring to the 128x128 and similar-sized CSTNs used in infamous Nokia phones... those are pretty easy to interface with an MCU as they have their own display RAM and controller.A Galaxy Note 3 is not so old and likely uses MIPI, it's possible to drive one but more difficult due to the much higher speed (although they may work down to lower speeds too.) Seemikeselectricstuff iPod nano display articlefor more information on that.
Uses for MAX4090? - Page 1
Forum section: electronics / projects

author: james_s
author_rank: Super Contributor
timestamp: February 18, 2017, 09:02:39 pm
content: So I have a few MAX4090 ICs, "3V/5V, 6dB Video Buffer with Sync-Tip Clamp and 150nA Shutdown Current" that I rescued from the e-waste bin, and by "a few" I mean 12,500 of them. I've used a couple for their intended purpose as a composite video buffer but I have at least hundreds of lifetime supplies of these things. Can anyone think of a novel or creative use for them? Anyone want any? Pay for postage and I'll stuff a few strips of them in an envelope.

author: james_s
author_rank: Super Contributor
timestamp: February 19, 2017, 02:06:22 am
content: Well PM me if you want some, I can take paypal for postage or you can do pre-internet style and send me a self addressed stamped envelope. I can probably stuff 100 or so into a regular envelope. If I lived another 100 years I would never manage to consume 12,500 of them.
[SOLVED] USI SPI data not in sync with the clock - Page 1
Forum section: electronics / projects

author: Kalcifer
author_rank: Regular Contributor
timestamp: September 06, 2020, 09:42:59 pm
content: I'm trying out the ATTiny84A's SPI mode for a quick test, and I'm running into a strange issue. I'm transmitting a byte of FF so I would expect the data line to be held high for 8 clock cycles, then to go low after transmitting. What appears to happen is that yes the microcontroller is transmitting the 8 1s and its clocking 8 times, but whats happening is that the data is offset from the clock pulses. The data appears to begin in the middle of one set of 8 clock pulses and end in the second. So for some reason there's a strange buffer delay or something idk. How do I fix this?Here's a quick snippet of the code that sends the data:Code:intmain(void){setupSPI();while (1){transmit();}}void setupSPI(void){//Puts the USI into 3-Wire mode. Uses DO, DI, and USCK pins for SPI communication.USICR|=(1 << USIWM0);USICR&= ~(1 << USIWM1);USICR&= ~(1 << USICS0);USICR|=(1 << USICS1);USICR|=(1 << USICLK);DDRA|=(1 << DDA4);//Set Pin 9 (USCK) to output the clock signal.DDRA|=(1 << DDA5);//Sets Pin 8 (DO) to transmit the Master's data.DDRA&= ~(1 << DDA6);//Sets Pin 7 (DI) to Receive the Slave's data.//Set PortA0 as an output pin for SS functionality. (May not need this later)DDRA|=(1 << DDA0);//Sets the pin as an output.PORTA&= ~(1 << PORTA0);//Defaults the output oft he SS (Slave-Select) pin to be a logical 0.}void transmit(/*uint8_t data*/void)//Transmits the 8 data bits.{//Use a loop to clock and shift the data register for transmission. Use a timer module?USIDR = 11111111;for (int i = 0; i < 8; i++){USICR|=(1 << USITC);USICR|=(1 << USITC);}}Here's what I see on the scope. You can see that the data begins in the middle of the clock pulses.

author: Kalcifer
author_rank: Regular Contributor
timestamp: September 07, 2020, 01:56:18 am
content: Never mind, I think that I just need some sleep. I wrote 11111111 as the data instead of 0b11111111 or 0xFF. Works fine now.Problem is solved.