Inkplate 6 resets during panel power-down (einkOff) on battery

TECHNICAL SUPPORT Inkplate
1

I’m running an Inkplate 6 as a battery-powered photo frame. On battery (never on USB), it resets during a full-panel refresh once the cell is at ~mid charge (~3.9 V). esp_reset_reason() reports WDT, but the panel shows a clean image the whole time, but it’s actually rebooting.

I split one refresh into its two phases, with an NVS breadcrumb before each so i could see what happened before the reset:

  • render: display.display(true)
  • power-down display.einkOff()

the reset is 100% in the einkOff power-down, 0% in the render. The image renders correctly every time; the board dies while shutting down deemingly.

This looks like the same unresolved issue reported in Inkplate-Arduino-library #56 and Inkplate-6-hardware #10 — both closed without a root cause.

Questions:

  1. Is this known / is there an issue with my board?
  2. Would a bulk low-ESR cap on the 3.3 V rail (to hold it above 2.7 V through the transient), and/or a cap + pull-up on the TPS3840 reset line, be the right fix?

Minimal reproduction attached (inkplate6_powerdown_repro.ino) — stock library only; flash on USB, run on battery, and it draws which phase it reset in. my next step was going to be testing it on an oscilloscope.

inkplate6_powerdown_repro.ino (4.0 KB)

Thank you so much!

2

Hi @s_hughes_anderson

I really appreciate the detailed and formulated question! Could you please confirm your exact Inkplate model and year, which board definition are you using, is your PCB Blue/Purple, as this is potentially an issue with an old batch of Inkplates where they would require a capacitor to handle the current spike. Fill me in on the details and I’ll we’ll see what we can do about this

3

Of course!

  1. model and year: Inkplate 6, the classic 6″. Not sure what year, but i bought it this year, order number 328895
  2. the standard “Inkplate 6” board (the original, not “Inkplate 6 V2”), using Inkplate Arduino library v11.1.0.
  3. the PCB is blue

I appreciate the support

4

hi @s_hughes_anderson , I see, it should be an e-radionica Inkplate 6 then. Check out this GitHub issue as pointed out by my colleague, we can’t provide official service for this as the warranty expired but you can add a capacitor to the board as described here to fix the resetting. Give it a try!

5

Ah interesting! I will try that

I’m surprised that the warranty is expired to be honest since I bought it a couple months ago. This is probably more feedback for your vendor (crowdsupply) but that do not communicate that at all on their webpage which is a little misleading, given they’re shipping product that has immediately expired!

But that’s a question for crowdsupply. I’ll try the capacitor trick!

6

@s_hughes_anderson my mistake entirely, these Inkplates have been manufactured a while ago, It was wrong of me to assume they were bought a while ago too.

You can have a warranty claim with crowdsupply as the unit is not functioning well, or potentially fix this unit with the capacitor trick.