Unanswered Questions

21,225 questions with no upvoted or accepted answers
15
votes
0answers
878 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 ...
7
votes
1answer
248 views

Subthreshold Analog Accelerator - How is current derived through two sub-threshold transistors in series?

Was browsing the following paper: Fick, Laura, et al. "Analog in-memory subthreshold deep neural network accelerator." 2017 IEEE Custom Integrated Circuits Conference (CICC). IEEE, 2017. When I ran ...
6
votes
0answers
163 views

Mystery 1974 vintage TI chip: N286M26

I inherited three of these Texas Instruments vintage ICs, marked N286 (regular size) and M26 (unusually large). The smaller pairs of digits on the right hand side, 74 and 18, are, I assume, the ...
6
votes
1answer
297 views

Analyze protocol used for Futaba VFD display, 3 data pins

I take apart a Samsung SMT-C7140 HD Unit (made obsolete by cable company, a shame) and found a nice display that I could probably reuse. It is a Futaba GL07-00006A (13-BT-246GINK). I tried to find the ...
6
votes
1answer
1k views

Receiver issues on STM32H7 interrupt-based SPI

I want to configure a simple interrupt-based SPI slave transmitter/receiver on a STM32H7 MCU. Even though I have quite a bit experience with the older series of STM32 ARM MCUs, it seems that a lot of ...
6
votes
3answers
4k views

Calculating the ESR of Capacitor

I try to calculate the ESR of a capacitor. I checked this datasheet: http://www.farnell.com/datasheets/2245214.pdf?_ga=2.167304311.817060034.1534770853-676261198.1531404202 I can see from the ...
6
votes
1answer
10k views

How can I model this common mode choke in circuit in LTspice?

How can the common mode choke in below diagram used in LTspice? By an inductor or transformer? How should be the circuit drawn in LTspice? I want to use this to filter out CM noises for single ended ...
6
votes
0answers
246 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 ...
6
votes
1answer
6k views

Altium Designer: Polygon does not connect to the pads on the same Net

I'm trying to put a plane shield using polygon pour and I realized that some object is not connected to my polygon. In the picture below it is clearly seen that the GND through hole is not connected ...
6
votes
1answer
480 views

What is the 3D radiation pattern of this chip antenna?

I know that the 3D radiation pattern of an antenna could be found by knowing the xy, xz and yz plane cuts and vice-versa. This process is pretty straight forward for a dipole antenna which has a 3D ...
6
votes
1answer
474 views

GPS Power consumption MTK3339 vs SirfIII for periodic logging application

I am currently working on redesigning a SirfIII based battery operated GPS logger. A MTK3339 based GPS module has been selected due to overall (advertised) performance. The GPS logger uses a ...
5
votes
0answers
76 views

What makes some commercial JFETs asymmetric?

In a MOSFET, the obvious cause of asymmetry is the fact that the source is tied to the body. But in a JFET, no such obvious answer exists, as the body, gate, and drain are all the same piece of ...
5
votes
1answer
98 views

Driving throttle sensor output to “play” on motorcycle

I'm trying to create device that allows to play music with motorcycle engines - something like that. I need help with electronic circuit to make that work. Bikes which I would like to use have fly by ...
5
votes
1answer
148 views

Rigid-Flex PCB Fabrication: Window opening vs slot opening

We had issue with one of the rigid-flex design cracking at the joint of Rigid and flex intersection. It is important to note that this is second batch of same PCB and PCB was not cracking in first ...
5
votes
1answer
435 views

How do I calculate a PCB antenna trace width?

I'm totally stuck here trying to find a single source that describes how to determine a PCB antenna trace width. I understand how to determine the length based on the targeted wavelength, but the ...

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