External watchdog module on I.MX7ULPEVK

[Raxesh-Oriya]

I read about EWM(External Watchdog Monitor) from data sheet but I do not see anything related to watchdog in design files of BB(SPF-29164_B1) and SOM(spf-29163_b2).

The question is, how can I make use of this module?

[igorpadykov]

Hi Raxesh

description can be found in Chapter 61 External Watchdog Monitor (EWM)

i.MX7ULPRMB2: i.MX 7ULP Applications Processor Reference Manual for Silicon Revision B2

EVM_OUT_b  PTB0(ALT12) can be found in SOM schematic spf-29163 p.17 P1B (DDR_SODIMM_EDGE

FINGERS)  MCIMX7ULP-EVK Design Files

Seems there is no driver in NXP BSPs, so one will have to write own one.

Best regards
igor

[Raxesh-Oriya]

Hi @igorpadykov 

I do not see EVM_OUT_b at PTB0 in SOM design file. If it all it is the there I can't use it with A7 core, correct? because PTA and PTB are for M4 core.

[igorpadykov · Accepted solution]

>I do not see EVM_OUT_b at PTB0 in SOM design file..

one can look IMX7ULPRMB2_Rev0_IOMUX.xlsx included in attachment tab Adobe reader

i.MX7ULPRMB2: i.MX 7ULP Applications Processor Reference Manual for Silicon Revision B2

EVM_OUT_b is muxed on PTB0(ALT12), it is accessable from both A7 and M4.

For A7 access one can use approach as in i2c-rpmsg driver 

https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/i2c/busses/i2c-rpmsg-imx.c?h=lf-5....

Best regards
igor