RF regulator and PWR monitor

[sukjinkang]

I am activating RF regulator via

self.enable_rf.switch_to_output(value=False)

as I have U7 chip installed. When I activate it, PWR monitor stops working. Is that normal? system_voltage and current_draw reads normally, but when RF regulator is enabled, numbers get weird, then starts outputting "none". I'm running the board off of 7.4V power supply, and not powering it via USB.

[maholli]

Haven't had a student encounter this before. Let me see if I can reproduce and I'll report back.

[maholli]

Ok I couldn't reproduce what you were seeing, but I did notice your syntax for turning on the RF regulator was wrong (NOT your fault but mine, I must have given you the wrong syntax previously. I'll go back and update any comments referencing that).

The way I have enable_rf set up in pycubed.py means we need to still treat it as a digitalInOut pin and not redefine the object. Therefore you control the state of the pin with cubesat.enable_rf.value=True or cubesat.enable_rf.value=False.

Nevertheless, I'm not seeing what you're describing:

• What's the current limit on your power supply set to? Make sure it's at least over 1A
• Are you able to reproduce my above screenshot from within the REPL? Knowing this will help me determine where to investigate next.

[sukjinkang]

from pycubed import cubesat
cubesat.enable_rf.value
True
cubesat.system_voltage
7.43667
cubesat.enable_rf.value = False
cubesat.system_voltage
26.2471

:(

[maholli]

Very interesting... let me know how it goes.

I have a suspicion this could be a ground loop issue somewhere.

• try it with and without floating your power supply
• with and without your laptop plugged into its power supply (if applicable)

[maholli]

Something else you can try is changing the I2C clock speed. This is more of a bandaid than a solution, but it might make things easier.

• Edit your on-board pycubed.py file line 91 to read: self.i2c1 = busio.I2C(board.SCL,board.SDA, frequency=100000) and then reload the board (ctrl+D from the REPL) then run your test again. While you're at it also try frequency=400000 and repeat.

[sukjinkang]

It seems to be a damaged board. Tried the same thing on a different board, and everything works fine. I must have damaged something during modifications/soldering.