Does i.mx8m mini have RTC module?

[triedgetech]

I have PICO PI i.imx8m mini by technexion. Their support doesn't reply back as usual, and they have no forum.

I want to connect backup button cell battery to i.mx8m mini carrier board, so that time/date is preserved on next launch.

But I couldn't find any pins on their carrier board's board to board connectors (X2, E1, X1) into which I'd connect such a battery. See p.15 -22 in this manual.

Another thread in here, about i.MX8 Mini has info that there's an RTC, but like I said, I couldn't find pins NVCC_SNVS_1V8 and VDD_SNVS_0V8 on the carrier board. I did find pins RTC_RESET_B, RTC_XTALI - but they're not available on the board to board connectors, so I'd have no access to them...

Do I have to use an external RTC then? Which communication protocol to use with processor? SPI or i2c?

[triedgetech]

Anyone?

[Rita_Wang · Accepted solution]

In the board you are using do not use the RTC, so you can not see them. In our NXP i.MX8MM EVK board you can see that we have used the internal RTC.

Here you can use the external RTC, both SPI or I2C interface are OK.