Unanswered Questions

9
votes
0answers
396 views

Problems while trying to flash a memory using openocd and jtag

I'm using openocd and jtag for the very first time in my life (after 30 years of playing with electronics), when I dump the flash using dump_image, I got a 4 byte sequence (0x80 0x01 0x59 0x18) in ...
8
votes
2answers
1k views

How to implement critical sections on ARM Cortex A9

I am porting some legacy code from an ARM926 core to CortexA9. This code is baremetal and does not include an OS or standard libraries, all custom. I am having a failure that appears to be related ...
6
votes
0answers
390 views

Typical zero sequence data for 80MVA transformer

I need to model a 80MVA transformer 132/33kV built in 1973. There is very little information on this transformer but I need to populate certain values in the model. Where can I find typical zero ...
5
votes
0answers
86 views

Does DIN rail have a weight limit?

Lots of industrial electronic hardware mounts to DIN rail. I would think there must be a weight limit to such mounting. But I haven't been able to identify one. Is there a defined weight limit, either ...
5
votes
0answers
63 views

GaN pulsed operation

Does anybody have experience biasing and pulsing a microwave GaN HEMT? I've just ordered a 10 Watt S-band transistor. I know all about bias sequencing. This application is pulsed. I've read about ...
5
votes
0answers
107 views

Winding method for barrel wound secondary center-taped EE core

I'm designing a high-frequency transformer, EE type core, with one primary, and a center tapped secondary. As the secondary current is relatively high and the window area is small, I will use copper ...
5
votes
0answers
215 views

Can't seem to write to spi flash

Well I've been stuck on this for a while, maybe 2-3 weeks at this point. I'm just not sure what I'm doing wrong. I'm trying to write to this spi flash part, and now I'm just running routines to ...
4
votes
0answers
59 views

Encounter: Hold time violation on clkgate

I'm trying to get rid of a clkgate timing violation. I have two of them and those are really big violations as you can see in this report: ...
4
votes
0answers
98 views

Buffer for 5V, 500ps to 10 ns pulses

I am trying to make a buffer for short, 5V pulses. The pulses are negative (form 5 to 0 V) and last for 500 ps to 10 ns (Half maximum, full width). The load is capacitive, around 50pF, and as close as ...
4
votes
2answers
325 views

Calculating reflections

I just solved a problem in my homework. I had to calculate the reflection waves and I was given the following data: Resistance R0 = 120 Ω line impedance Ri = 90 Ω resistance at input Rb = 1 kΩ ...
3
votes
0answers
40 views

Blocking RF on same side as PCB antenna?

I have a penta-band GSM transciever on a 4-layer board, along with a matched chip antenna. Similar concept to ...
3
votes
1answer
29 views

Altium Database and Footprint density

I am curently trying to use database in altium. But i have one big question ? I am taking the way to get one database entry by resistor value. But after tha for example, for one 100k 0805 resistor, ...
3
votes
0answers
60 views

To pulse or not to pulse

It is accepted practice to maintain lead acid batteries at a float voltage of roughly 2.3 Volts per cell .The precise value depends on battery type and battery chemistry and ambient temperature .We ...
3
votes
0answers
63 views

Convert SLA laptop battery to NIMH

I have an old laptop that uses a SLA Battery and I'm wondering what sort of circuit would be need to convert the charging circuit for NiMH Cells. Many manufacturers were able to do some time ago but ...
3
votes
0answers
42 views

Using crystal in LTspice (where to get values for RCL)?

I'd like to simulate a schematic in LTspice driven by a crystal. An capacitor representing the crytal (as a resonant circuit) however it needs some specific values. Is there a table of common values ...

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