Hi there. I have a question about the jumpers (J3, J5, J8, J9) on the Caravel demo board. "https://github.com/efabless/caravel_board/tree/main/firmware/chipignite" 1. Does "cutting a trace" mean physically cutting the jumper trace with a cutter knife? I ask because I'm not very familiar with PCBs. 2. I wanna apply a voltage of 5V to vdda1 and vdda2. Do I need to apply an external voltage after cutting the J9 trace to achieve this? Thanks in advance for your help!

(1) Yes, "cutting a trace" means getting out a hobby knife and slicing through the metal (preferably checking resistance with a multimeter before and after to make sure you cut all the way through). (2) You don't need to cut any traces to apply independent voltages to

vdda1

and

vdda2

. Both are independent supplies and unconnected to anything on the board; they have to be jumpered to something to be powered.

vdda2

is conveniently located next to a

3V3

pin;

vdda1

is unfortunately not located next to a power supply at all, and 5V is not readily accessible from the board even though it is an input from the USB (not that you would necessarily want to power an analog circuit off of the USB supply).

Thank you. @Tim Edwards I have a follow-up question regarding the

vdda1

supply, as I seem to have missed something. I am trying to supply 5V to

vdda1

and

vdda2

. As

vdda

are independent supplies, as you mentioned, I understand that I can directly apply the voltage without needing to cut any traces. However, I am concerned about the fact that the

vdda1

and

vdda2

pads are internally clamped to

vddio

(3.3V) within the caravan. Wouldn’t this make it difficult to ensure that a proper 5V is being applied? If I were to use 5V, would it make more sense to apply the 5V via

J5

after cutting the relevant traces?

No, they are not clamped to

vddio

. Each of the

vdda

domains has its own independent clamp. I have tested the Chipalooza test chip with driving the overvoltage detectors with voltages up to 5.5V. This works without any issues.