M8P - external power for CM4

General Discussion
1

Basic Information:

Printer Model: Mercury One Hydra
MCU / Printerboard: Manta M8P
Host / SBC: CM4

Hi, I have one problem with manta m8p and cm4. I supply 24v from PSU to POWER section, and 5V to USB-C. Jumper VUSB near USB-C port is shorted. If i understand correctly, CM4 should be powered from external 5v source in that configuration. I don’t know why, but it’s not turning on. No diode is flashing and it’s not visible on remote access. Do i need to do something more? Right now when BTT Relay shuts down ~10s after turning and the printer on RPI gets no power.

  1. All switches above CM4 [eeprom-WP, NEXTRST, RPI_BOOT, USB-OTG] are to the left (off)

  2. When BTT relay is supplying 24v CM4 starts booting, but has no time to finish.

What should i check to get it to work? Added additional picture to visualize how it’s wired up.

btt-octopus-ssr-wiring
btt-octopus-ssr-wiring3112×1080 582 KB

2

I could be wrong but I read this:

image
image1920×866 153 KB

as saying the jumper should be shorted to power the MCU and the CM in order to allow diagnostic work and upgrades prior to connecting the board to the printer power supply. I don’t see a way to isolate the CM from the 5V DC-DC converter on the board.

As I see it “normal” operation is jumper removed and no 5V at the USB connector.

If I’m correct there is no way for the CM to control the relay unless the relay defaults “on” at power up for long enough for the CM to boot. You could wire the relay between the PS and the SSR but that doesn’t give the relay authority over the extruder heater.

Have you reached out to BTT support?

3

This may be useful. It does seem that the relay is on at power up

1 Like
4

No, the CM4 should be powered by the M8P. Disconnect any power supplies attached to it.

Did you change any of these?

There is a switch below the USB C connector. What is it set to?

What does this mean?

What is the part number of the CM4 you’re working with?

How did you image the Micro SD Card that you’re working with?

What is the box to the right? Is this the extra 5V power supply you’ve added?

Can you add an HDMI monitor to the HDMI0 output on the M8P? That would be the best way to tell you what’s going on.

In any case, I recommend going back to the start:

  1. Just provide power to the M8P that has the CM4 on it. No 5V power, No relay, No box to the left.
  2. Put the switches back in their default positions
  3. Connect an HDMI monitor (if possible)
  4. Turn power on and observe what happens
5

I probably broke the usb-c power, glad i wasn’t using that ::laughing:: Thanks for the link, i think flashing firmware and changing pin on the board to startup hot is the way. I hate how bad BTT documentation is. Auto shutdown relay is especially bad.