Unanswered Questions

29,056 questions with no upvoted or accepted answers
24 votes
0 answers
2k views

Switch from JTAG to SWD with bitbang sequence on STM32F103VB

I am trying to switch from JTAG to SWD without any external devices. Why? Because I would like to use the SWO pin to send a stream of logging information to another device. To accomplish this ...
11 votes
1 answer
539 views

Home made passive tablet pen

I have an old wacom tablet at home, its really big and I'd like to use it but I've lost the pen for it. It uses pens with passive LC circuitry. The board creats an EM-field (I can see it on my ...
9 votes
0 answers
401 views

How to understand a complex diode-resistor function generator circuit?

I'm reverse-engineering a CRT anti-pincushion circuit and it uses a complex diode-resistor circuit to approximate the function X-k×X×Y², where X and Y are the deflection voltages. My question is if ...
9 votes
1 answer
498 views

Incrementing net name for group in Eagle

I want to make 50 copies of the block below, but I need incrementing numbers on each of the net labels (these will go to a connector). I do not want each block connected to the other blocks. It would ...
8 votes
0 answers
242 views

Estimate base-spreading resistance from Gummel-Poon model

I'm attempting to calculate the base-spreading resistance of BJTs from manufacturer-provided SPICE models, which use the Gummel-Poon model. This Agilent publication (Internet Archive link here, if ...
8 votes
0 answers
2k views

Is JTAG faster than SWD for debugging on an STM32F with STLINK-V3SET programmer?

There is a new STLINK-V3SET programmer that someone dropped off on my desk today. It supports USB 2.0. My thinking is that if SWD is the bandwidth limiter in the signal chain then a new programmer isn'...
7 votes
0 answers
242 views

Clock generator output off by a factor of sqrt(2)?

I'm using the Si5351A-B-GM clock generator with the NX5032GA-25.000M-LN-CD-1 (25 MHz, 8pF) crystal. The fragment of the schematic is shown below (the rest of the schematic omitted for clarity): ...
7 votes
0 answers
151 views

Extremely long net in Xilinx synthesized design labeled "async_path". What's it for?

I used Vivado to synthesize a small design for the Xilinx xc7k-160t-1. The design includes a fifo instantiated with Vivado's XPM macros which crosses clock domains from 100.8MHz to 200MHz. When I ...
7 votes
0 answers
358 views

x86 Motherboard Bring Up - Intel Tiger Lake UP3 CPU

For those who has experience with Intel x86 motherboard design and bring up. I'm in the middle of motherboard bring-up that has Intel Tiger Lake UP3 CPU. Seems like I had a good run so far at power-up ...
7 votes
2 answers
1k views

How to meaningfully compare Xilinx MCS files?

Brief I have two different boards with Xilinx designs that might be the same design. I am trying to compare the different MCS files to see if the designs in them are in fact the same design. Can this ...
7 votes
1 answer
877 views

Modeling scalar control of PMSM

I have met with a scalar control algorithm for a permanent magnet synchronous motor. I haven´t heard about it before so I decided to develop a dynamic model to further analyze this control algorithm. ...
7 votes
2 answers
248 views

Phase shift near saturation mitigation in input stage amplifier -- How does this work, why does this work?

I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer. Apologies for the quality... this is the best scan I could find. The design is furnished with the ...
7 votes
1 answer
5k views

STM32F0xx UID decoding

In my project, I need to make readable 96-bit UID. In STM32F0xx reference manual RM0091 section 33.1 Unique device ID register, it is described how the number is encoded: ...
6 votes
0 answers
136 views

Vivante video memory size?

I'm using an NXP i.MX 8MP, with Vivante GC7000UL and GC520L GPUs. Using the Etnaviv open source drivers. For the life of me, I can't figure out how much video memory is made available to the GPUs, nor ...
6 votes
0 answers
180 views

Identify kind of cable with markings such as "WE-B 2 PAIR" on the jacket

While cleaning out our back yard shed, I came across a coil of cable of a kind that I have never seen before (image below). It was left here by the previous home owner, who worked in some kind of ...

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