13

Study the circuit board and the components on it. Trace along the suspected positive and negative power tracks. Look for components that have identifiable positive and negative terminals. Electrolytic capacitors have their negative terminals clearly marked. If you can find data sheets for any integrated circuits on the PCB, see which are the power and ...


8

Quick note: some barrel power jacks incorporate mechanical switches ( that sometimes are used to short the center pin to ground when unplugged among other things) , so unless the part only has two terminals it is wise to insert a plug ( ideally one with nothing connected ) before making your electrically connectivity tests.


7

You appear to have pin 2 and 3 swapped on your TPS62120 symbol. Pin 2 should be ground. Pin 3 should be enable.


6

This is not specific to VHDL, but generally here's how to interpret compiler error messages: Error (10500): VHDL syntax error at clothes_washer.vhd(22) near text ")"; expecting an identifier, or "constant", or "file", or "signal", or "variable" The keyword "Error" means a serious problem that ...


5

The above is "old school". That type of connector falls apart at very high frequencies. There's nothing wrong with it so long as your signals are, say, sub 100Mhz-ish. Here are two more modern options that are workable and cheap. You have to design these into your PCB before you lay it out. https://www.newark.com/keysight-technologies/n2766a/...


4

Internet search to find the manual or photos showing the AC adapter (usually the polarity is marked on the label). Older products can sometimes be found on eBay. Meter on diode test scale. If it shows a diode in one direction and higher in the other it's probably the second direction. Most digital DMMs have the red lead as positive in diode test mode. This ...


4

There are several ways to go on this. You can use a through hole pad, and then solder wires where you need them. You can also use a SMD type pad, that is just exposed copper that can be probed You can use something like a 5003 from keystone You can use something like the 5015 from keystone


4

The cheapest and smallest probe connector is a via hole that fits the tip of the 10x scope probe, with a ground via next to it that fits the tiny ground spring attached to the probe. It sure beats a fancy probe connector that isn't there because there wasn't enough space to put it in...


3

After a lot of testing, I happened to try it with the boot configuration that uses 64 MHz HSI oscillator. That worked! So after further testing, it finally saw this piece of the clock tree documentation: Whenever STM32H7 is configured to use PLL1 P channel as the CPU clock, the trace clock is automatically switched to PLL1 R. I had the R channel disabled ...


3

Last time I did this, it was a while ago, I used a Cypress FX2LP USB micro. It has a FIFO interface which is very FPGA friendly, and on the USB side it uses bulk transfers. No issues maxing out USB2 bulk bandwidth with python/libusb. Pros: 480 Mbps is great if you need it, bulk USB does the error correction, and the chip is not difficult to use. python/...


3

OK, the official old school connector for insane speed digital signals is the mictor, and AFAIK is still used for the trace port of some high end DSPs. That said, it's for differential signals and needs a special analyzer. For general purpose you didn't say which frequencies are you going to use… for low frequencies (about 150MHz) the rectangular strip ...


3

Maybe a controller/voice box for advertising displays. Or maybe it’s a virus vector for a worm transmitted via the USB port when you plug it into your computer.


3

That is perfectly normal. The compiler has optimizations on, and it sees you have an empty for loop which does nothing so it optimizes it away. Since there is now an empty subroutine it can also be optimized away and it does not need to be called.


3

It's not easy. You don't get that far with a scope because the encoding on the line is so hard to observe. However you can scan for basic activity. Note that on 1000BaseT (from my experience) you often see continuous carrier activity, while on lower speeds you only see activity when you send some data. This at least lets you know if there is actually ...


2

It's a steering wheel control box for the stereo so you can retain steering wheel controls buttons with aftermarket stereo


2

Have you set portA to digital I/O. Usually it defaults to analogue inputs at powerup? If left in analogue mode it will function as a digital output but when read will return 0x00. Read the A to D converter section of the data sheet and find the register which needs to be written to change portA from analogue mode to digital mode.


2

oh my, that's not an appropriate board layout. Glad I insisted on a picture! Your ground return paths are nowhere near your supply lines, your trace layout is random, to put it mildly, and your decoupling caps are too few and partially not where they're needed. Redo that design. Put the capacitors directly adjacent to the supply pins. No exceptions. Bottom ...


2

GDB throws the connection if the clock configuration is not correct and SWO is enabled. I also tried the method above and got SWO working at the initial HSI 64 MHz frequency but SWO was lost when the frequency was changed to using the PLL output. The solution works for STM32H745 to enable SWO output (SWV in STM32CubeIDE). A simple method is to keep PLL1_R ...


2

It seems like there is a fundamental conceptual disconnect here. The ACS712 output is offset to mid-rail to facilitate reading voltage when the current can be either positivist or negative. The ACS product literature calls this "bipolar." Some ACS current sensors are unipolar (although they may be offset slightly above ground anyway). It seems like ...


2

We use small 0.1" header pins/assemblies like these all the time to provide test point/probe capability. Something like these, from Samtec. They work well up to hundreds of MHz, if you're careful about how you connect the probe and gnd lead to the pins. Going along with that, for high speed signals you want to provide a generous amount of signal ...


2

but I don't know what '\252' means. This is an octal value. It's equal to 2 + 5*8 + 2*8*8 = 170. Another example: '\123' is octal for 3 + 2*8 + 1*8*8 = 83. Next I changed the variable to a char instead of an unsigned char and ran the same print test_var, I got an output of $10 = -86 '\252' 170 is greater than 127, so when represented as a char (which is a ...


1

The amp seemed to work perfectly with the wire replacing the diode Most likely explanation: The opamp can power the transistor's base through the wire, but not through the diode, which is in the wrong direction. As you noticed, this points to one of the resistors between the transistor bases and the supplies being open circuit, so no current flows in the ...


1

Well i though this problem was kinda weird but when i found out cubemx generated this code "__HAL_AFIO_REMAP_SWJ_DISABLE();" in "void HAL_MspInit(void)" function. I kinda laughed ^^ and delete it. People who have a similar problem hope will see this answer before spending much time...


1

The Cortex-M7 processor has internal flag that identifies debugger accesses as either cacheable, or non-cacheable. Non-cacheable is the default, and it causes all requests to bypass the data cache. Openocd tries to set the flag in stm32h7x.cfg, but that only works for low-level access debuggers. ST-Link is a high-level debugger (you can check with monitor ...


1

Agree about the probe. Also, switching power supplies, especially low-cost ones like yours, usually have a minimum load requirement. 10% is a common requirement "to stabilize the magnetics" (ooooold app note phrase). Without this, the supply is not guaranteed to maintain regulation.


1

Post a picture of your physical PCB, I might be able to help you. Everything looks good at the schematic but: You are using avrdude to program it ,so I suppose you need it to have a bootloader), and connect the programmer (possibly a FTDI Basic) to RX/TX pins. How come you are using ISP for programming using avrdude? Are your connections clean after ...


1

The clicking sound is made by the electromechanical relays on the board (4 black boxes). They have electromagnet inside and it attracts the two or more contacts (they connect/disconnect in order to control the current flow). This switching of contacts is what You hear. The board might have faulty power semiconductors (if there are any) controlling the motor. ...


1

Here its how i configured it (im able to debug step to step and place breakpoints with the SWD port & a stlink v2 usb on a STM32F103VE) on Windows 10 The important thing was to set the openocd folder as launch folder (cwd): { "version": "0.3.0", "configurations": [ { "showDevDebugOutput": true, ...


1

According to STM32F446RETx Datasheet: 3.13 Clocks and Startup: "On reset the 16 MHz internal RC oscillator is selected as the default CPU clock. The 16 MHz internal RC oscillator is factory-trimmed to offer 1% accuracy at 25 °C. The application can then select as system clock either the RC oscillator or an external 4-26 MHz clock source." Some ...


1

Can a Pull Down Resistor help here? It might. It depends on your type error. OpAmp inputs are high impedance. So they tend to pick up noise or static charges, if their inputs are not connected to a fixed potential. A pulldown resistor is one way of solving this issue. and also a Series resistor to the input will help? No. As I said. OpAmp inputs are high ...


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