From 27791518448a708e9bf08d464c1f11c516d08b9c Mon Sep 17 00:00:00 2001 From: Maciej Gibowicz Date: Thu, 25 Mar 2021 16:16:33 +0100 Subject: [PATCH] [EGD-6331] Add cellular low power documentation The documentation describes how to get into and out of sleep mode for Cellular. --- .../service-cellular/doc/README.md | 27 +++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/module-services/service-cellular/doc/README.md b/module-services/service-cellular/doc/README.md index c3f7bef81326004418cc5e2631d1bf8e68ffea72..13ff477c21e5f79a4987bd5dcd0060709d78078f 100644 --- a/module-services/service-cellular/doc/README.md +++ b/module-services/service-cellular/doc/README.md @@ -22,3 +22,30 @@ It can be request of external phone number but also emergency call request,USSD The logic has to recognize the request and apply proper action. ![](call_request_handling.svg) + +## Cellular sleep mode + +Conditions for cellular to enter sleep mode: +* no ongoing call +* 5 seconds of inactivity in communication over UART + +Conditions for cellular to exit sleep mode: +* incoming URC +* any activity in communication via UART to the modem + +Host Enables GSM Module to Enter into Power Saving Mode: +* Pull DTR and WAKEUP pins from LOW to HIGH, and trigger the module to enter into power saving mode +* Set AP_READY pin as invalid +* Disable UART clock +* CPU sentinel release block frequency request + +Host Enables GSM Module to Exit from Power Saving Mode: +* Enable UART clock +* Host pulls DTR and WAKEUP pins from HIGH to LOW, and triggers module to exit from power saving mode +* Set AP_READY pin as valid + +GSM Module Enables Host to Exit from Power Saving Mode +* Host receives the change of RI pin, then exits from power saving mode and enters into normal mode +* CPU sentinel block frequency decreasing below 132 MHz +* The wake-up described in the point above takes place +