Hi everyone, I’m trying to figure out which Caravel I/O pin connects to a specific signal in the Sky130 chip. I’m working on someone else’s design and having a hard time finding which I/O pin the signal is mapped to. Could someone point me to the file(s) I should be looking at?

@Ashish Rimal For caravel, the pin assignment is here.

user_project_wrapper

io_in[0]

connects to the

mprj_io[0]

pad and

io_in[37]

connects to

mprj_io[37]

. For caravan,

io_in[13:0]

connect to

mprj_io[13:0]

,

analog_io[10:0]

connect to

mprj_io[24:14]

and

io_in[26:14]

connect to

mprj_io[37:25]

The 18 analog connections to the gpio are as above but offeset by 7. See https://github.com/efabless/caravel_user_project/blob/main/verilog/rtl/user_project_wrapper.v and https://github.com/efabless/caravel_user_project_analog/blob/main/verilog/rtl/user_analog_project_wrapper.v for details. Is that the information you wanted?

thank you so much @Mitch Bailey this is what i needed. I have another question. If i want to test the circuit ( ring oscillator) on my chip, do i need to supply vdd,vcc externally from caravel board pin ? or if i connect caravel board to my computer using usb, it will supply those biasing voltages? this is specific question but i am asking in general.

@Ashish Rimal Sorry, I can’t help you there. @Leo Moser @Tim Edwards

The board is configured with a hard-wired jumper to VCCD1 (1.8V). If you are running the circuit off of VCCD2 (also 1.8), or VDDA1 (3.3V) or VDDA2 (3.3V), then you need to add a jumper on the board to the "1V8" or "3V3" pins. Unfortunately on one of those (VDDA2, I think) the pins are not next to each other on the board so you need a jumper wire, not just a little shunt.

@Tim Edwards I am trying to test my circuit on chip but without programming the board( just send input and read output) is it possible to do that, if I am using caravel i/o pins? If not Also I am trying to find the pin mapping for pad on chips to the M.2 pcb on the caravel board but I couldn’t find it. So I can send input and output to the chip directly. Can you provide me pin mapping for M.2 pcb?