[Bug]: eink updates causing packet loss

[andrekir]

Category

Other

Hardware

Other

Firmware Version

2.1.0+

Description

every packet transmit and receive triggers the e-ink screen to redraw, with the log message "Updating E-Paper..." and looks like nRF52s can't handle well both at the same time.

@caveman99 suggested moving e-ink updates to their own RTOS task.

Relevant log output

No response

[nickpascucci]

Following on from discussion here: https://discord.com/channels/867578229534359593/871553168369148024/1143163122396450928

I flashed my T-Echo with a build at b47c9c16 with a change on line 35 of src/graphics/EInkDisplay2.h:

bool forceDisplay(uint32_t msecLimit = 100000);

This prevented the display from updating as frequently, and I was able to send 26 messages (A-Z) to a nearby T-Beam with no missed acknowledgments. Previously I would have more misses than acks. This seems to strongly point to the e-ink updates being an issue in a hot loop.

[GUVWAF]

Added the high-priority label as it seems to cause ACK failures quite easily, because transmitting triggers the touch button (on a T-Echo) causing multiple e-ink updates. Conclusion of a discussion on Discord was that the missed packets are caused by the screen update blocking ISR access. Therefore, that needs to happen in a dedicated RTOS task.

[marek22k]

Is there a solution or a workaround without having to compile the firmware yourself?

[GUVWAF]

I think for the T-Echo this is not an issue anymore now that it has partial updates which also causes it not to trigger the touch button anymore.

I can confirm it's still an issue with the Heltec Wireless Paper which only has full updates.