hybridfree/eevblog-posts huggingface dataset:
STM32H503 USB bootloader - Page 1
Forum section: electronics / projects

author: Neilm
author_rank: Super Contributor
timestamp: May 31, 2024, 07:00:54 pm
content: Hi Guys,Has anyone every tried to use a STM32H503 processor with the USB bootloader? Specifically - I am trying to use it without a crystal and it does not seem to enumerate when I connect.The layout of the traces is not wonderful - but the total length is only 18 mm so I doubt it is an imedance issue, although the rising edge looks more like a Mayan pyramid than a smooth rise.Getting the Nucleo board has been a pain as it has not arrived. I ordered it, designed the schematic, laidout the board, bought the board, built the board, tested the board and it has still not arrived.If someone can tell me if they have been able to use it like this I can help narrow down this issue.ThanksNeil

author: aliarifat794
author_rank: Regular Contributor
timestamp: June 01, 2024, 01:17:38 pm
content: The STM32H503 does have an internal oscillator calibration feature, but this may not be sufficient for USB operation without an external crystal.

author: Neilm
author_rank: Super Contributor
timestamp: June 01, 2024, 06:20:47 pm
content: Quote from: aliarifat794 on June 01, 2024, 01:17:38 pmThe datasheet seems to suggest the clock will synchronise to the start of frame in the USB packets
stm32h750 vbat pin charging feature - Page 1
Forum section: electronics / projects

author: jealcuna
author_rank: Contributor
timestamp: September 15, 2021, 02:19:31 am
content: Hi folks,I have seen a couple of schematics to double check the design for vbat pin by using a cr2032 holder and them implements a diode from 3.3 to vbat pin, which I think is for charging purpose or for avoid to leave floating the pin in absence of a battery. However, it is no clear for me since the datasheet indicate that vbat pin can charge a battery, so diode should not be necessary. Am I missing something?
STM32L051 External oscillator pin out - Page 1
Forum section: electronics / projects

author: pyrohaz
author_rank: Regular Contributor
timestamp: April 20, 2015, 09:15:34 pm
content: Hi guys,I'm designing a low power system around the STM32L051K8 and I'm under a fair bit of confusion from the data sheet. I'm going to be using the LQFP32 version and reading the datasheet, I can't tell whether the external crystal oscillator pins (PC14 and PC15) allow for the connection of a 32.768kHz crystal or not. Reading the datasheet, it seems the pinout page is full of errors:http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00108219.pdfI'd really appreciate if someone could help clear this up for me? If not, where could I find this information?Thanks!

author: 6thimage
author_rank: Regular Contributor
timestamp: April 20, 2015, 09:51:18 pm
content: From a quick glance I can't see the errors on the pinout page. But from page 69 the OSC32 pins (PC14 and 15) are designed to be used with a 32.768 kHz crystal, which is referred to as the LSE (low speed external) clock - page 67 lists the clock characteristics.

author: pyrohaz
author_rank: Regular Contributor
timestamp: April 20, 2015, 11:53:23 pm
content: Quote from: 6thimage on April 20, 2015, 09:51:18 pmThank you for your time! On page 33, the chip is listed as an LQFP32 yet the image names it a QFN32 package (I'm assuming their the same size...) It also names PC14 as OSC_IN and PC15 as OSC32_OUT which is where the confusion is I think! Following the actual pinout table, PC14 is actuall OSC32_IN so I think it must just be that image that's incorrect.
STM32L051K8 Standard Peripheral Library - Page 1
Forum section: electronics / projects

author: pyrohaz
author_rank: Regular Contributor
timestamp: May 15, 2015, 02:55:42 pm
content: Hi all,I've posted this in the ST forum as well as here, I'm just more accustomed to this forum so I'm going to ask here too!Throughout my time programming STM32 microcontrollers, I've used the standard peripheral libraries. Having recently designed my latest product around the STM32L051K8, I thought there would be a standard peripheral library for this too. I've tried searching but can't seem to find one anywhere and everything is pointing me towards using STM32Cube.So I've downloaded STM32CubeMX but it currently seems really limiting for my application. I've developed my application on the STM32F051 (hoping the code would be relatively easily ported) and I need the ability to do things like change the SPI data size on the fly etc. I could realistically program everything in low-level register form but since I've already got everything programmed using the standard peripheral library, it seems a waste of my time to start over.Where can I find/port the standard peripheral library for the STM32L051K8?Cheers!

author: splin
author_rank: Frequent Contributor
timestamp: May 16, 2015, 06:26:52 pm
content: You'd do better posting on the 'Microcontrollers & FPGA's' forum. For example there's this thread, and earlier ones, expressing (mostly negative) opinions on 'Cube'https://www.eevblog.com/forum/microcontrollers/st%27s-%28stm32cube%29-software-ecosystem-is-terrible-how-can-we-fix-it/A std peripheral library for the STM32L051 probably doesn't exist as ST have moved to Cube.You should be able to get plenty of advice on the Microcontroller forum as to which devices with a std peripheral library, if any, have the same peripherals as the STM32L051.If you compare the reference manuals for the 051 and L051 you may find that your existing library doesn't need much tweaking - although, for example, I see the SPI device has been modified especially wrt DMA so perhaps not trivial.Middleware code often obfuscates and even complicates the user code adding several layers of indirection which you end up having to unravel when debugging - so you may have to learn what's going on at register level anyway if it doesn't work properly first time.
[SOLVED] Schematic symbol not generating and PDF pin names not copyable - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: October 28, 2024, 10:54:16 pm
content: Hi,I am using a STM32L4R9VIT6 and need the Altium symbol. Because it is a relatively large IC I would rather copy-paste the names and pin numbers pairs to avoid any errors (not out of laziness), but:- if I copy and paste the pin names (or any other data) from the PDF datasheet, when I paste them they all paste as a the same character: a question mark inside a square box- I tried downloading it from the STM32 page:https://www.st.com/en/microcontrollers-microprocessors/stm32l4r9vi.html#cad-resourcesbut it does not generate the symbol. I tried multiple browsers and multiple computer but it just does not download them.Are there any other places/resources where I can cut and past pin name and number from?Thank you

author: MarkL
author_rank: Unknown
timestamp: October 29, 2024, 02:21:22 pm
content: I had a similar problem and I found a handy list of pin mappings in the MCU database that comes with STM32CubeMX.For your processor, it's installed in ./db/mcu/STM32L4R9V(G-I)Tx.xml. This file also has all the alternative functions for each pin which was useful during layout to optimize pin location vs. AF, since many AF's can appear in several locations. Some simple parsing will be needed, but the format is simple. The pin descriptions start at line 78 or so, and the "Position" value is the pin number.I've attached the file from CubeMX 5.0.1 (that's old) to save you some time, and in case they don't provide this XML format anymore in the current tool.

author: Giaime
author_rank: Regular Contributor
timestamp: October 29, 2024, 02:38:50 pm
content: For STM32, I usually get the symbol and footprint 2 ways:download the source files for the demoboards, usually they are in Altium format, and copy the symbol and footprint from there;or internally from Altium using the built-in library ("Manufacturer Parts Search")Do you have trouble by downloading the Ultra Librarian files from ST website? Although not my preferred method, I've used this in the past, and the download works for me. Which CAD tool do you use? Depending on the CAD tool, you need to follow Ultra Librarian directions on how to import the models in your specific CAD.

author: ricko_uk
author_rank: Super Contributor
timestamp: October 29, 2024, 05:14:54 pm
content: Thank you both, all good and valid ideas/suggestionsUltra librarian generated a wrong pinout and some STM32 micros are sold for 19USD...I also found out that the pinout can be exported from CubeIDE and CubeMX. You select the micro (for example to create a new project) then there is a drop down menu with two options "Export pins" and "Export pins with alternate function".
STM32WB Flash Writting Data Alighment - Page 1
Forum section: electronics / projects

author: TrickyNekro
author_rank: Frequent Contributor
timestamp: August 30, 2023, 11:26:29 am
content: Hi!Yet again, I do have a small question about the STM32, that I can not really get around my head.The STM32WB supports writing to the Flash, the Flash access can only be done with a 32bit word. 64bit of data ( two words back to back ) have to be written in the Flash at each time.Now the question, in order for an data alignment error not to occur, the data have to be written in an address that is double word aligned.To my understanding that means that the Address has to be divisible by 8. This is a check I would like to perform before attempting to write to the Flash to minimized possibility of error.Is my assessment right?Thanks in advance,Lefteris

author: eutectique
author_rank: Frequent Contributor
timestamp: August 30, 2023, 11:45:29 am
content: Yes.I did not use STM32WB parts, but with STM32L4xx the reason for 8-byte alignment is the correct generation of internal ECC. This might be true for WB as well.

author: moffy
author_rank: Super Contributor
timestamp: August 30, 2023, 11:47:28 am
content: Your understanding appears to be correct:https://community.st.com/t5/wireless-mcu/can-we-write-1-byte-data-into-flash-in-stm32wb55/m-p/180456You write 2 by 32 bit words (8 bytes) aligned on addresses which must be a multiple of 8 bytes.

author: TrickyNekro
author_rank: Frequent Contributor
timestamp: August 30, 2023, 12:04:17 pm
content: Thanks!

author: AndyC_772
author_rank: Super Contributor
timestamp: August 30, 2023, 12:33:35 pm
content: It's the same on the newer G series parts too.

author: DavidAlfa
author_rank: Super Contributor
timestamp: August 30, 2023, 02:40:01 pm
content: Not required if the core supports unaligned access.The M4 processor will, the M0+ won'tFor the M0, declare the source variable /struct/buffer adding:__attribute__((aligned( 8 ))).For example:Code:__attribute__((aligned(8))) myStructType_t mystruct;This will align it to 8 bytes = 64bits.

author: Jeroen3
author_rank: Super Contributor
timestamp: August 30, 2023, 02:48:36 pm
content: The alignment capabilities of the cortex are irrelevant. Hardware restrictions in the flash controller of the part determine if this is possible or not.Flash is usually read and written per word and flash words are not core words. Eg: for the WB this is 72 bits, yet for the F4 it is 128 bits. It differs greatly.
STM32WB IO IO clamping on FT inputs? - Page 1
Forum section: electronics / projects

author: ConnorGames
author_rank: Regular Contributor
timestamp: July 05, 2023, 05:22:33 pm
content: I've recently been working on a design with an STM32WB module and USB-C. I want to monitor the voltage on the USB-C CC pins (across the 5.1K resistor), but it appears that in a dead-battery situation the system is not able to bootstrap because some parasitic impedance form the STM32 GPIO pins is pulling the CC lines down, but only sometimes? When I measure the CC pins with a meter on diode-test and no power supplied to the board, I sometimes get ~0.65V, and sometimes get 1.1V (the expected value for a 5.1k resistor with my meter's test current). I always get 1.1V with VDD applied to the board. I haven't been able to find a rhyme or reason why I am getting the inconsistent results, I'm guessing it depends on the voltage on some capacitance inside the chip or module. These are supposed to be FT_fla GPIOs that don't have a protection diode to VDD, but I have a feeling that there is more to the ESD protection structure than is disclosed in the datasheet (or even in AN4899). Does anyone have any idea what is going on here?EDIT: If it maters, IOs are PC0 and PC1 on the STM32WB5MMG
STN LCD Inconsistent contrast across X axis - Page 1
Forum section: electronics / projects

author: pyrohaz
author_rank: Regular Contributor
timestamp: December 06, 2014, 02:06:26 am
content: Hi all,I've been working with an LCD that I bought from the far lands of Asia and I'm having problems with an inconsistent contrast across the whole X display. The inconsistency only occurs for lots of active pixels and isn't present for only a few active pixels, therefore I'm attributing it potentially some lack of voltage somewhere?The LCD is:http://www.ebay.co.uk/itm/291044732253I'm pretty much using their initialization code on my STM32F0 with a 3.3V supply.I've attached two pictures showing this inconsistency.Any ideas?Thanks,

author: amyk
author_rank: Super Contributor
timestamp: December 06, 2014, 04:36:39 am
content: Image-dependent variations in contrast suggest that the ITO resistance is too high/driver is too weak to supply the needed current. You can try adjusting the VLCD booster voltage or the bias ratio.

author: pyrohaz
author_rank: Regular Contributor
timestamp: December 06, 2014, 11:32:37 am
content: Quote from: amyk on December 06, 2014, 04:36:39 amAha! Thank you for your input! I increased the VLCD booster voltage to higher, reduced the net contrast and its got rid of the inconsistent contrast.Thanks for the help!

author: amyk
author_rank: Super Contributor
timestamp: December 07, 2014, 05:31:02 am
content: The optimal VLCD usually varies between modules, so if you just used the default settings you'll get a display but it might not be optimal for the ITO/layout and LC material used for a particular model. Just don't go beyond the specified range (+11.5V for this one) or you can damage the IC.

author: pyrohaz
author_rank: Regular Contributor
timestamp: December 08, 2014, 10:13:04 am
content: Quote from: amyk on December 07, 2014, 05:31:02 amI was worried about this so I contacted the seller of the item and what they said agrees with what you've told me! Increasing the VLCD satisfies the contrast problem. I will calculate the actual LCD voltage to ensure that this isn't over the 11.5V limit.Thanks for the help!
Stocko Edge Connector Alternative - Page 1
Forum section: electronics / projects

author: Shay
author_rank: Regular Contributor
timestamp: September 03, 2025, 04:43:43 pm
content: Hey.I was wondering if anyone know similiar connector to this stocko 7238 edge connector:notice the key on the 2nd pin. it is important, otherwise the user can connect it backwards.I tried searching on google and it seems there are lot of alibaba lists for this but they want MOQ if 100+. I need only like 20-30 for now.Thanks
Stop me nuking my bike battery. (Dashcam, ACC, Battery Tender) - Page 1
Forum section: electronics / projects

author: freman
author_rank: Contributor
timestamp: May 14, 2021, 05:21:36 am
content: Hi,Wondering if anyone has a better way of doing the following.I have a dashcam on my bike, it has 3 wires for power (+ - ACC) the + and - are permanently connected to the battery, the acc is so it comes on with the bike. All good. Works wonderfully.Comes time to download some footage off it, and it's not in the best spot to just pop the SD card out, but has a really nice (As in fast, and functional) wifi option, also all good.If I leave the bike on ACC it has a constant current draw of close to two amps (head and tail lights), which nukes the battery quick fast, I thought sweet, I'll just plug the battery tender in, nice use for it after I went all that effort installing the plug for it (before I knew how much the bike was pulling) and the battery still went flat (cos that baby does 800ma).I could probably solve this with a SPDT switch, but I'd rather it be automatic.What I'm thinking is running the ACC line to the 12v on the battery tender, so whenever the tender is plugged in the camera is powered. but in order to stop that also back powering the ACC circuit (and constantly running the camera) I'd have to put in a couple of diodes.One of them from the battery tender to the battery, one from the acc line to the acc input.See attachedBut I'm worried about the effect of the voltage drop on the battery charging capacity of the of the rather intelligent battery tender.Is there another way of doing this that anyone knows of?

author: freman
author_rank: Contributor
timestamp: May 24, 2021, 05:47:11 pm
content: Currently leaning towards a merit connector and a DPDT relay with common ground throughout the bikes electrical system.Plug a 1amp 12v DC supply into the merit connector, it disconnects 12v from the batter and ACC from ACC, joins them with each other and the 12v from the merit connector.This leaves the charger port alone and keeps it purely for chargingMind you this post is 3 am genius and may look quite dumb after some sleep
Stop PCHAN (high side) of a totem pole driver from body-diode conducting upwards - Page 1
Forum section: electronics / projects

author: epicedium
author_rank: Newbie
timestamp: November 10, 2015, 12:42:08 pm
content: So I have a simple totem-pole driver made up of two mosfets (P high, N lowside). It drives the OUTPUT to either 3V3 (1A), GND, or float.However, sometimes the OUTPUT of the driver is connected to a weak 10V signal. In this unusual usage case, my circuit needs to float in a way which doesn't affect the external 10V signal. Obviously I disable both mosfets.In practise however, the 10V is dragged down by the 3V3 bus via the body diode on the Pchan.I've been trying to LTSpice a revised top-side with two back-to-back P channel mosfets, but I can't seem to get it work. Is it possible with minimal components? (i.e. two p chans and a resistor or two)?Or is there a better way? In my last design I gave up and replaced the top-side driver with a solid-state relay, but the footprint and cost is prohibitive for this new design. I looked into Jfets, but I'm a bit thrown by the terminology in the datasheets and the Rds-ons look pretty terrible.What's my best bet?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 10, 2015, 12:58:46 pm
content: Simple: add a diode.Kind of sucks for 3.3V, but if you can tolerate the drop...There are ICs that have to handle this. CANbus drivers are an example. They use diodes. (They only need to make a few 100mV of signal, so an extra 1.4V drop isn't a problem there.)You can use an ideal power diode circuit, which uses a MOSFET and comparator.You could also try a current limit, which can be done with one or two transistors, if you don't mind extra output resistance.Tim

author: epicedium
author_rank: Newbie
timestamp: November 10, 2015, 01:06:22 pm
content: Interesting, the diode placed from the high-side Pchan into the output? I'm pretty sure I could tolerate the drop from a little schottky like an NXP PMEG3020EH

author: suicidaleggroll
author_rank: Super Contributor
timestamp: November 10, 2015, 04:53:30 pm
content: You should be able to do it with back to back Pch MOSFETs. Attach the sources together and the gates together, run a pullup from the common gate to the common source for when your drive signal is high Z, and that should be it.
Storage and cataloging for the modern SMT "junk box" - Page 1
Forum section: electronics / projects

author: mark03
author_rank: Frequent Contributor
timestamp: July 30, 2013, 07:20:42 pm
content: Hey everyone,What's your solution for managing an inventory of spare surface-mount parts? I have some boxes with drawers and dividers holding thru-hole components sorted into decade bins, but for SMT I think I need the following:Between 10x and 100x the number of containers I had for through-hole (of course they will be 1/10 or 1/100 the size)--each value R or C in its own containerEasy to fish out tiny components like 0603 passivesAt least some bins ESD safeCheapSuggestions?

author: Unknown
author_rank: Unknown
timestamp: July 30, 2013, 07:57:08 pm
content: I like thesmtzoneSMT enclosures. Last time I looked, they had them with one layer of compartment or two layers (one in the lid) and in ESD-safe and normal versions. You should be able to find them on eBay. They were fairly affordable ($20 or so) and stackable, so hundreds to thousands is quite possible. It might get tedious to retrieve parts if you actually have ten of these enclosures stacked, though.Note that there are two versions, one of them is suited for small parts, the other may leak tiny (eg. 0603 or smaller) parts.

author: brainwash
author_rank: Frequent Contributor
timestamp: July 30, 2013, 08:22:42 pm
content: I just keep the tape parts and write the values on the back of the tape. They take less space this way and are easier to handle.You might want this:http://www.amazon.com/practical-resistor-capacitor-electronic-component/dp/B006G0ILS6

author: mark03
author_rank: Frequent Contributor
timestamp: July 31, 2013, 05:02:46 pm
content: Hmmm... those 128x arrays of micro bins look pretty nice. I wonder if they are ESD safe, for mosfets and ICs.But I think I like the idea of book-style storage in plastic sleeves even better, at least for R's and C's. Does anyone know where I can buy those plastic sleeves separately (like the ones in the parts kit in the amazon link)? I can get them for 35mm negative strips, but that's a bit wide for this purpose---you could fit twice as many compartments on a page, easy.

author: wraper
author_rank: Unknown
timestamp: July 31, 2013, 09:09:56 pm
content: http://www.ebay.co.uk/itm/300502242242The same non ESD boxes are 2x cheaper.
Storage time effects of BJTs - Page 1
Forum section: electronics / projects

author: Faringdon
author_rank: Super Contributor
timestamp: October 23, 2023, 07:02:22 pm
content: Hi,The attached shows a circuit on the LHS, which runs deeply saturated. However, it appears to switch at the same time as the one on the RHS.Does anyone agree with this?, and do you have a simulable model showing this storage time effect properly?The storage time effects seem not to be written into any simulator's BJT models.(LTspice and jpeg attached)

author: moffy
author_rank: Super Contributor
timestamp: October 23, 2023, 07:22:01 pm
content: Without waveforms and with a moderately complex circuit who can comment on what is happening?I ran a simulation to show just the saturation effect and got faster recovery for lower saturation e.g.

author: Marco
author_rank: Super Contributor
timestamp: October 23, 2023, 09:27:25 pm
content: You have to measure the recovery at the same drive strength, also base current during saturation isn't necessarily a measure of the "strength" of saturation.I think you have to find a BJT model with RCO set, that seems to be part of the saturation modeling.
Storing lithium thionyl chloride batteries on a shelf for 2 years? - Page 1
Forum section: electronics / projects

author: incf
author_rank: Frequent Contributor
timestamp: July 03, 2025, 03:39:54 pm
content: Lithium thionyl chloride batteries go bad when no load is applied to them. They must have a load applied periodically or they will go open circuit in a few months.I've got a situation where I need to store a large number of ER18505 lithium thionyl chloride batteries on a shelf for one to two years.I was wondering if any commercial products exist to accommodate this need? (something that connects to or holds the batteries and periodically applies a small load to keep them alive)

author: Gyro
author_rank: Super Contributor
timestamp: July 03, 2025, 05:39:43 pm
content: Have you a reference for that information? Lithium thionyl chloride are normally stated to have a shelf life of 10 years, one brand 40 years.

author: voltsandjolts
author_rank: Unknown
timestamp: July 03, 2025, 05:46:52 pm
content: They don't go bad, they just passivate.Depassivate before use with e.g. 50mA load for 30mins (that's what I use for bobbin AA thionyl).Or ask manufacturer for recommended procedure.

author: Gyro
author_rank: Super Contributor
timestamp: July 03, 2025, 05:59:55 pm
content: Agreed, ask the manufacturer if it is critical.The passivation shows up as an initially higher impedance, a big difference from open circuit. I would expect this to happen in a much shorter time than [1-2 yearsa few months]. It is a very brief phenomenon and doesn't take much drain to restore normal impedance.

author: tggzzz
author_rank: Super Contributor
timestamp: July 03, 2025, 06:12:55 pm
content: Quote from: incf on July 03, 2025, 03:39:54 pmI too am interested in:a decent reference for that phenomonona (vague) definition for how much load needs to be applied to avoid it - i.e. numbers not adjectivesEven mA, nA, pA, fA would be useful

author: incf
author_rank: Frequent Contributor
timestamp: July 03, 2025, 06:23:24 pm
content: Quote from: Gyro on July 03, 2025, 05:39:43 pmWe use them in a product line and have spoken with the manufacturer. I was fairly sure "going bad" when stored improperly was just how they work. Now need to reinvestigate.Quote from: voltsandjolts on July 03, 2025, 05:46:52 pmInteresting. Will tryQuote from: Gyro on July 03, 2025, 05:59:55 pmPerhaps my impression was an artifact related to the circuit implementation of the product they go into.Quote from: tggzzz on July 03, 2025, 06:12:55 pmRoughly 2% of the capacity of the cell per year is required else it goes high impedance.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 03, 2025, 06:24:20 pm
content: I never heard of this passivate / depassivate, but it does seem to be a real thing. Apparently this is both the mechanism that gives these batteries a shelf life of 20 years or more, and a mechanism that can cause some problems after long storage, or when current draw is highly variable.https://html.duckduckgo.com/html?q=Lithium+thionyl+chloride+passivatehttps://www.swe.com/media/files/files/114e6391/lithium-battery-passivation-de-passivation-whitepaper.pdf
Stp component model - Page 1
Forum section: electronics / projects

author: ebclr
author_rank: Super Contributor
timestamp: June 17, 2016, 03:30:49 am
content: I just found a free software on windows store that help you on display you Stp models on windows 10 and I would like to shareI get the program on Microsoft store for free suigested by windows while try to open file, it's simple but effectiveWedge is the software name
STP04CM05 LED driver - default register settings ? - Page 1
Forum section: electronics / projects

author: mags
author_rank: Newbie
timestamp: January 20, 2012, 01:35:49 pm
content: Hi,I have several IR LEDs to be driven in unison. Up to 4 strings will be needed.I'm considering the STP04CM05 driver:http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00177556.pdfThis has a serial input (SDI, CLK pins), so each string can be switched individually.I only want to switch them all together (using the OE pin).So my question is, what is the default state for the registers (on or off)?If they are all ON after startup, then I can do away with the need to program, which is obviously much simpler.Figure 16 of the datasheet implies that this is the case, but it's not stated explicitly.Has anyone out there used this chip (or a similar one) and know the answer?Thanks.
STP1612PW05 LED driver - Page 1
Forum section: electronics / projects

author: alizare368
author_rank: Regular Contributor
timestamp: June 19, 2019, 12:41:52 pm
content: HiI used these codes to run the RGB LED DRIVER(stp1612pw05), but it does not work.the PWCLK is 2M.Code:#define SPI_SCLK_LOW_TIME 200#define SPI_SCLK_HIGH_TIME 1uint16_t SPI_1(uint16_t byte_out){uint16_t byte_in =0;uint16_t bit;for(i=0;i<16;i++){//LE pin is lowHAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_RESET);for (bit = 0x8000; bit; bit >>= 1){/* Shift-out a bit to the MOSI line */HAL_GPIO_WritePin(GPIOB,GPIO_PIN_4,(byte_out & bit) ? GPIO_PIN_SET : GPIO_PIN_RESET);/* Delay for at least the peer's setup time */for(int i=0;i<SPI_SCLK_LOW_TIME;i++){}/* Pull the clock line high */HAL_GPIO_WritePin(GPIOB,GPIO_PIN_5,GPIO_PIN_SET);///* Shift-in a bit from the MISO line *///if(HAL_GPIO_ReadPin(GPIOC,GPIO_PIN_8)==1)//byte_in |= bit;///* Delay for at least the peer's hold time */for(int i=0;i<SPI_SCLK_HIGH_TIME;i++){}/* Pull the clock line low */HAL_GPIO_WritePin(GPIOB,GPIO_PIN_5,GPIO_PIN_RESET);}//LE pin is highHAL_GPIO_WritePin(GPIOB,GPIO_PIN_9,GPIO_PIN_SET);HAL_Delay(1);}//return byte_in;}while (1){SPI_1(0xffff);}
straight shank .8mm drill bits - Page 1
Forum section: electronics / projects

author: waytec
author_rank: Newbie
timestamp: September 23, 2017, 11:59:10 pm
content: Does anybody know of a source of these drill bits.Was able to get them off ebay ... but now searches only show them bundled with other sizes...Wayne

author: BrianHG
author_rank: Super Contributor
timestamp: September 24, 2017, 12:06:59 am
content: https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20170923160651&SearchText=0.8mm+drill+bit

author: waytec
author_rank: Newbie
timestamp: September 24, 2017, 11:42:53 am
content: Ohh thank you very much...Thought I had searched everywhere....Thanks again

author: Kleinstein
author_rank: Super Contributor
timestamp: September 24, 2017, 02:29:17 pm
content: 0.8 mm normal HS drills are not that special. One should get them from regular tools supply for metal working. In my supplier's catalog they are at 1.50 Eur for a pack of 10 (the simple type, thus no TiN, but dark FeN finish).
Strain gauge info - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: November 18, 2016, 06:49:26 am
content: I have an old strain gauge I'm trying to use for a project. I got it mostly working, but there are two problems. First, I'm having trouble deciphering the data on the label. Whoever wrote it doesn't seem to understand proper units and SI notation. I'm trying to find the gauge factor, and the scaling factor to read out force in Newtons.Second, can anyone identify the connector so I can find a proper mate? My makeshift pins won't hold up for long. It has a metal shell, is about 20 mm in diameter, 11 mm high from the top of the square base, and I can't find a manufacturer or part number anywhere on it.

author: bagnoz
author_rank: Newbie
timestamp: November 18, 2016, 02:53:44 pm
content: I have found a few heuristics when dealing with funny units:Almost every time someone writes Kg [Kelvin·gram] they mean kg likewise MM [~megameter?] probably means mm sometimes MV  means mV and so on..."cps" is cycles per second, aka Hz.The reading of Kgm [Kelvin·gram·meter] really confused me at first, but then I found that WP:EN says:"kg·m, sometimes run together as kgm (kilogram-metre, actually kilogram-force so kgf·m) is a unit of torque""kgm is sometimes an abbreviation for kilogram (proper symbol kg)"I think the latter makes more sense, but my straing-gauge-fu is not good enough to be sure.I'm assuming the kg are meant as a unit of force, so I will substitute daN .I guess what is meant is the following:maximum working range daN 500 mNdisplacement ratio mm/daN [millimeter per decanewton]2 mm/Nminimum reliable force mg  ? 10 µN 20 µNself-resonant frequency Hz 85 Hzoutput (mV/daN)/V ? this would be a ratio which could be written as (mV/V)/daN, 0.1 (V/V)/kN or just as 0.1 kN^-13 (V/V)/kNoutput (mV/mm)/V ? this would be a ratio which could be written as (mV/V)/mm, (V/V)/m or just as m^-11.5 (V/V)/mmaximum displacement mm ±1.1 mmmaximum force daN 10 daN = 1 hNmaximum applied tension V 8 VBut this all might be wrong, because I don't understand what is be meant by "FORCE RATE Kg/mm".
Stranded (not individually insulated) wire for reduced AC losses - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 20, 2022, 10:55:02 pm
content: Neat, there's a paper on it:http://inductor.thayerschool.org/papers/stranded.pdfI always figured it'd be good for ballpark 10-20% reduction in AC resistance (at frequencies where solid wire suffers skin/proximity effect losses); seems it can do quite a bit more than that, actually!Mind, the difference, relative to ideal litz cable, is a factor of 5 or more (or, including arbitrarily deep proximity effect, and eddy currents from fringing fields, the sky's the limit..), but compared to solid -- it's something!Probably a 10-20% figure is still ballpark reasonable for random hookup wire, that you don't have control over strand size/count and twist pitch; and in any case, you have the rather severe problem of wasted space due to thick plastic insulation. But on a pound-for-pound basis, say on cores where you're not space limited -- relatively oversized cores, toroids -- that can be less of an issue.Tim

author: coppercone2
author_rank: Super Contributor
timestamp: September 21, 2022, 10:18:48 pm
content: well you can actually crimp it properly without crazy stuff so thats something

author: Carel
author_rank: Regular Contributor
timestamp: November 14, 2022, 10:33:04 pm
content: I read this idea and tried it. Yes, it gave me an increase of 15 mm in range. With some tuning, thicker wire, some lower impedance I may get some more range. I am not familiar with the black magic of coils, this spoils a lot of wire, so I am not worthy of Litze wire at this moment.Thanks!
Strange analog circuit problem with grounding - Page 1
Forum section: electronics / projects

author: Mad ID
author_rank: Regular Contributor
timestamp: January 22, 2014, 09:49:19 am
content: Hello,I have developed an FSK (HDX) RFID reader which works great when it is powered by a clean isolated lab power supply. The reader has a buck converted at the input. If I ground the lab power supply it works the same.However, if I power it through an isolated low quality 12V wall adapter which is very very noisy my RFID reading range falls to 1cm. What I have noticed it that the noise itself is not a problems, it's the fact that it is isolated + noisy in combination!When I ground the system the reading range goes to normal regardless of noise. If I try to probe my analog signals with a non-isolated scope, as soon as I touch the signal ground with scope ground problem is of course gone.Please help, I want to understand the problem so that I can avoid it in the field.Cheers.

author: Mad ID
author_rank: Regular Contributor
timestamp: January 22, 2014, 12:53:03 pm
content: New info, ground potential difference between earth ground and crap power adapter is 85Vrms AC.This is the problem definitely, still not sure why this would be a problem for RFID communication. So my reader antenna is changing potential to ground at 50Hz rate. Anyone?

author: poorchava
author_rank: Super Contributor
timestamp: January 22, 2014, 06:34:19 pm
content: Have you torn apart the adapter? Maybe it's the parasitics in the adapter that cause this problem?
Strange behavior of W25Q64JVSSIQ - Page 1
Forum section: electronics / projects

author: adhoc_user
author_rank: Contributor
timestamp: October 02, 2024, 06:25:37 am
content: Normally sleep current of the system is 12uA. On some boards it reaches 20uA. After applying pressure to the flash chip and resolder it, the consumption goes down to 12 uA. What would be the problem?

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 02, 2024, 06:37:23 am
content: Quote from: adhoc_user on October 02, 2024, 06:25:37 amBad solder joint?Jokes aside, the difference in current draw seems to be roughly the difference between the standby current and power-down current of this flash chip. Which would suggest that on the problematic boards, the flash chips don't stay in power-down mode (which I assume is what you set the flash chip to when your system is in "sleep mode"?) If so, one possible cause given your symptoms could be the /CS pin, if otherwise other flash commands seem to work as expected.

author: Salitronic
author_rank: Contributor
timestamp: October 02, 2024, 10:13:01 am
content: Do you have a pull-up resistor on the CS pin? (the schematic snippet you shared does not include it)If you refer to the power-up/down section of the datasheet you'll see that the CS must always follow VCC on power-up/down. Failure to do so can result in an unknown power-up state, and even though you can typical reset the flash memory though software reset, I've observed issues in the past when I forgot that pull-up myself.Further assuming that you are putting the entire circuit in sleep mode, you need to make sure that the GPIO pin of the MCU is not floating that CS pin, it needs to be held high during the sleep mode.If you don't have the pull-up, I'd suggest adding it and retesting the power consumption.

author: adhoc_user
author_rank: Contributor
timestamp: October 02, 2024, 10:26:43 am
content: recently found out when i put oscilloscope probe on SPI_MISO line consumption drops 12uA.https://lowpowerlab.com/forum/moteino-m0/spi-miso-needs-pull-resistor/After reading this entry, I added pullup resistor on MISO line. It seems worked.
Strange Behavior on DC/DC Converter - Page 1
Forum section: electronics / projects

author: tyguy2
author_rank: Unknown
timestamp: August 19, 2018, 06:47:38 pm
content: Hello,I've been tinkering with the PAM2401SCADJ (https://www.diodes.com/assets/Datasheets/PAM2401.pdf). I'm using it in an application that runs off a single AAA battery, and boosting that to 3.6 volts. Looking over the datasheet, this chip should easily supply 100 ma (see page 3, first graph.) However, I can't load it down with more than 35 ma; after that the voltage drops significantly. I'm not sure if I'm reading the datasheet wrong or have just wired it incorrectly. I have the MSOP-8 package, so no PG pin for current limiting. Currently, when I try to power a small motor, it will turn on and off quickly, and the oscilloscope confirms the device is sending short pulses to it. On smaller loads, it sends continuous voltage. Am I tripping some sort of over current protection?

author: tyguy2
author_rank: Unknown
timestamp: August 19, 2018, 07:16:02 pm
content: Update:I connected the RSET to Voltage in, and now it seems to be supplying more current, and it occasionally does supply full current, but it still fails to consistently reach its full output and voltage.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: August 19, 2018, 07:58:39 pm
content: A motor will pull more current when it ramps up to speed. Could that be the problem?Sent from my SM-G930V using Tapatalk

author: tyguy2
author_rank: Unknown
timestamp: August 19, 2018, 08:09:40 pm
content: Quote from: ahbushnell on August 19, 2018, 07:58:39 pmI wouldn't think so. The motor intermittently reaches full speed, but if the initial current draw was the issue, once it sped up, it would maintain its speed.Edit: Just to confirm, I spun the motor by hand while powering it, no go

author: tyguy2
author_rank: Unknown
timestamp: August 20, 2018, 03:37:18 am
content: Figured out the issue, I had to reduce the inductance of the coil from 2.2 uH to 1.5 uH

author: thexeno
author_rank: Regular Contributor
timestamp: January 19, 2022, 11:05:11 pm
content: Hi, personal curiosity: what part exactly did you used? It should normally work with higher inductor, not viceversa.
Strange driving of RS-485 transceiver - Page 1
Forum section: electronics / projects

author: dobsonr741
author_rank: Frequent Contributor
timestamp: July 05, 2024, 01:03:31 am
content: I found a strange way of hooking up an RS-485 transceiver in a slave peripheral I was reverse engineering.Has anyone seen this before? The TX signal drives the enable pin, not the TX input. Why?

author: oPossum
author_rank: Super Contributor
timestamp: July 05, 2024, 01:09:08 am
content: Collisions don't produce bus contention. Same as CAN bus.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: July 05, 2024, 01:53:11 am
content: Quote from: dobsonr741 on July 05, 2024, 01:03:31 amYes, this becomes CAN-like with almost open drain, but that needs care with non fail-safe BUS drivers.Below is another slight variant, where TX drives DI and Inverted TX drives Enable, that has a couple of advantages.The PNP in this case has a slower turn off than turn on, so the 485 driver pulses the line the reverse way, then floats.This means you do not need the hassle of managing the Enable timing. It drives and auto-reverses.Note also the BUS is pre biased, as the floating state has lower noise margin. The pulse time is enough to kick it over the threshold Schmitt.It would be best suited to the skewed threshold / failsafe RS485 parts.There are some RS485 parts that now have this 'auto-direction monostable' inbuilt. (THVD1406, THVD1426)

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 05, 2024, 02:03:04 am
content: Yeah, it just makes the idle level (high) of the TX out as a "recessive" state. Yes, kinda like CAN. While probably some care must be taken, this is a very simple trick.
Strange ground dip on linear reg startup, is this ok? - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: August 18, 2022, 10:05:47 am
content: The following image is probed using the ground spring clip at the MCU IO pins.Purple is between AVCC and GNDYellow is a GPIO output (same GND point as above).The capture is taken when the power switch is flipped on which sends 12V to 7805 and the 5V rail starts up (purple)The yellow GPIO output has a pcb trace that goes to the other side of the PCB which I'm assuming is where this ringing is coming from?MCU doesn't start for 65ms, so it's not running yet. the GPIO will be high Z.Obviously there is some ringing below ground at startup on the GPIO pin. ~600mV for around 19us.I'm trying to determine how bad this is and if I need to rework the boards to protect the MCU from being damaged over time.Thanks in advance
Strange issue - FT231X - 2.5V TX Line - Page 1
Forum section: electronics / projects

author: docmur
author_rank: Regular Contributor
timestamp: December 02, 2017, 09:48:53 pm
content: Hey GuysI have a circuit revolving around the FT231X, I've attached the schematic portion of the chip. When I probe the RX / TX lines, the RX is at 3.3 volts, which is correct, but the TX line is sitting 2.5 volts, and I can't figure out why, this problem exists If I populate a bare bones board, with just the USB module and voltage regulator. What would cause this much signal loss? Is it safe to use a pull up to force the TX line up to 3.3v?ThanksDocmur
Strange layout of current sense IC - Page 1
Forum section: electronics / projects

author: eTobey
author_rank: Super Contributor
timestamp: March 09, 2023, 04:05:20 pm
content: Hi,i am not a professional, but i found something that looks strange to me. Its from a yamaha ebike motor (PW-ST).Its a current sensor of a phase of the brushless motor.The fuse is rated for 30A, but these traces, even if they are short, look quite stupid to me. Also the manufacturer does suggest both pads to be on a plane.Anyone know of a reason for this strange layout?CheersToby

author: coromonadalix
author_rank: Super Contributor
timestamp: March 09, 2023, 05:05:26 pm
content: must be an hall effect current sensorand please don't start threads about the same things / double threads ...you ask about a ichttps://www.eevblog.com/forum/projects/current-sensor-mpq8113-any-good/and you se in the pdf the working principles / applications

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 09, 2023, 07:30:49 pm
content: What traces?You mean the pads? Those are covered in solder and component leads. And are very short. Copper is an excellent conductor, you can pinch down quite a bit and stay within thermal limits as long as the heat has somewhere to go. Traces only reach steady state limits over long lengths (some inches).I would pour copper over/around the pads personally, but this here is far from a disaster.Tim
Strange LED COB failure - Page 1
Forum section: electronics / projects

author: torsj
author_rank: Newbie
timestamp: March 16, 2021, 10:55:00 am
content: I've got several white LED COBs that have gone dark in the same manner in one specific installation. The COBs does not fail at the same time, but it is unknown if the failure is abrupt or gradual. Other installations with the same driver and COB has not failed. The COB is specified as 8W, 450mA and 20VDC (max), and has a 3x5 geometry. The manufacturer of the COB is unknown to me.There are no visual problems with the COB, such as discoloration, cracks or an uneven surface. Also, the temperature handling is adequate.The forward current through the COB is less than 1 µA up to 20V. The reverse current is 0A down to -1V and then increase to -15mA at -2.4V.Since there is a reverse current through the LEDs, the bonding wires must be intact. Because of the zero forward current I guess that something has happened to the PN-junctions in the chip itself that has destroyed the diode function but kept the reverse current behavior.I have two questions:How can the forward current be zero with a normal reverse current?What can have caused this to happen?Thank you for any suggestions

author: Wolfram
author_rank: Frequent Contributor
timestamp: March 16, 2021, 11:05:06 am
content: Could there be a separate reverse voltage protection diode in the package? If the main LED strings have gone open-circuit, then that would explain your measurements.

author: torsj
author_rank: Newbie
timestamp: March 16, 2021, 11:44:25 am
content: Quote from: Wolfram on March 16, 2021, 11:05:06 amYou are right.I've now removed the silicon gel and phosphor, and that of course broke the bonding wires. The current from diode tester on the multimeter is enough to light up the chips separately, so the LEDs themselves are OK. I also tried to run enough reverse current to heat up any protection diode, and it the Flir showed it in a corner of the COB.I was at my wits end, never heard of a COB with a built in protection diode.But now we have a regular case of burned bonding wires.Thank you!
Strange optocoupler behavior  - Page 1
Forum section: electronics / projects

author: atgeek
author_rank: Contributor
timestamp: April 21, 2018, 01:01:52 pm
content: I'm using 4 optocoupler for switch some relay with an attiny85. Each optocoupler is connected with a 150 ohm resistor to the attiny gpio. I've noticed that I had left the ground unconnected on the optocouplers anode but surprisingly they works the same , turning on the relay. How is it possible? Maybe due to some capacitance beetwen the anode and the emitter?

author: madires
author_rank: Super Contributor
timestamp: April 21, 2018, 02:27:43 pm
content: Shouldn't the LED's cathode be connected (or switched) to ground? Could you please post a circuit diagram?

author: Seekonk
author_rank: Super Contributor
timestamp: April 21, 2018, 05:33:37 pm
content: I assume no return path for any LED. In the past I'd say that couldn't happen. The reverse voltage is passing through the other opto LED when one or more pin is opposite. Older LED were speced with a reverse voltage of 5V even though I'd never seen one with less than 75V PIV. Some new LED are really less than 5V. What is your opto?

author: mikerj
author_rank: Super Contributor
timestamp: April 22, 2018, 10:13:48 am
content: Quote from: madires on April 21, 2018, 02:27:43 pmAgreed, having the LED anode grounded makes no sense unless the OP is driving the cathode with a negative voltage.