Wakeup GPIO configuration in Serial LTE Modem

RE: Wakeup GPIO configuration in Serial LTE Modem

Hakon — Fri, 09 Feb 2024 10:02:03 GMT

This is a question to our GPIOTE IP. GPIOTE is timed with 16MHz, so a cycle is 62.5ns. SLM used level (GPIOTE_PORT) interrupt for low power, the minimal time required should be longer than one cycle, for example 100ns~. If you remember the app_uart in legacy SDK, the default triggering time is 100ns. NOTE for edge interrupt (GPIOTE_IN), the input signal should be <= 8MHz.

What's more, if SLM has the PIND_IND defined, there is a hardware handshake mechanism, that when the PIN_WAKEUP has waken up SLM, it will in turn assert PIN_IND to indicate that it's ready. With this there is no need of timer control on MCU side for asserting PIN_WAKEUP.

RE: Wakeup GPIO configuration in Serial LTE Modem

Hakon — Thu, 08 Feb 2024 11:51:58 GMT

CONFIG_SLM_WAKEUP_PIN=6 DK button #1
CONFIG_SLM_INDICATE_PIN=2 DK LED #1

The two PINs could be assigned with any avaialble GPIOs.

It looks like that they want to reuse the UART2 TX and RX pin, which means that UART2 must be disabled before the pins are re-assigned. We have not tested this setup.

RE: Wakeup GPIO configuration in Serial LTE Modem

Nikint — Wed, 07 Feb 2024 15:32:30 GMT

Hi Hakon,

Adding more queries in same thread.

We had gone through Serial LTE modem documentation. We understand that, cellular modem's wakeup logic is active LOW.

So, we want to know, minimum duration of pulse required to acknowledge the wakeup event in cellular modem.

Thank you.

RE: Wakeup GPIO configuration in Serial LTE Modem

Nikint — Mon, 05 Feb 2024 11:42:15 GMT

Hi Hakon,

We will be waiting for the reply.

Thank you.

RE: Wakeup GPIO configuration in Serial LTE Modem

Hakon — Mon, 05 Feb 2024 11:39:18 GMT

Hello,

I have asked the SLM guy for info.