Please suggest how to debug this FTDI device related issue. I was trying to run

python3 caravel_hkdebug.py

What do you get when you do

lsusb

? Do you see the FTDI device listed?

@Tim Edwards I am using Ubuntu22.04 on virtual box inside Windows. I get following output running

lsusb

please don't post the same thing in multiple places, it wastes peoples time

Sure, will take care of it in future.

"permission issue" means you either needed to run the command sudo or you need a rule file for ttyUSB in udev.

@vks click devices->usb-> select the ftdi device of ur chip from options. it will work. virtual machine u have to manually select the usb devices

After installing

sudo pip3 install pyftdi

and adding

sudo

to

python3 caravel_hkdebug.py

, getting output as seen below. Does it mean I am able to communicate with caravan now? I still do not see outputs running commands

lsftdi

and

ls /dev/ttyUSB0

My main issue is that GPIO pads in my chip are set in analog mode but I still see default pulse signal on one of GPIO pads meant to output analog signal. How can I reset caravan to bring GPIO's in state as defined in

user_define.v

file.

Yes, you are communicating correctly with the Caravel chip now, as shown by the vendor and project IDs you got back. There is no command "lsftdi", and doing "ls /dev/ttyUSB0" will only show you that the device file exists, which means you got back from those commands exactly what you should expect to get back from those commands. If you are getting a pulse on the outputs, it's probably because the "blink" program, which is used for testing before shipping, is programmed into the SPI flash chip. Erasing the SPI flash is a good first step; if the GPIOs are configured to be in the correct state on power-up, and you don't need the processor, then erasing the flash should improve things.

Thanks for update. Should I select option (6) to erase flash ?

I just tried that from

caravel_hkdebug.py

and it didn't do anything---probably that function has not been exercised for a long time and has become broken by other code changes in the script. It's a bit more work, but I suggest just writing a simple program with an empty

main()

function and compiling it and flashing it.

I used option (6) to erase flash and it worked. Led D3 which was blinking stopped and pulse signal on GPIO pad also disappeared. But I am faced with another issue. The circuit I am measuring uses 5V fet's but I used vccd1 pin to power this circuit. Is there any option to give 5V external supply to vccd1 via jumper on board or any other way ?

what is the voltage at vccd1 right now? there is a way to cut the trace jumpers on board and provide externally.read on j8 and j9 jumpers on pcb

Thanks @samarth jain for these inputs. I will check tomorrow connecting jumpers and update. Is 1.8v on

vccd1

internally generated? Need not give it externally?

Yes Vcc d1 is generated by pcb regulator as shown below. U have to cut trace if u want externally

That's great, will be really helpful.

j3 is for vccd1 1.8v. yes if u cut it the vccd1 u can provide from outside

Yes, that should work. Be careful with driving vccd1 to 5V. vccd1 is not connected to anything outside of the padframe, but it is connected to a low-voltage clamp. I am not sure what the clamp rating is, but it is not designed for 5V use.

Ok, will take care of it. Need some help in locating

J8

jumper in caravel schematic. Not able to find it. https://github.com/mattvenn/caravel_board/blob/main/hardware/development/caravel-dev-v5-M.2/caravel-dev-v5-M.2.pdf

At the very top of the board, toward the left-hand side.

Able to locate in layout but not able to find it in caravel board schematic. Please see if you know location in schematic.

Here, in the middle of the schematic:

Thanks very much @Tim Edwards. I had hard time searching for it.