From fa4f717051ae75867c697b624bf35db72e9ac7a3 Mon Sep 17 00:00:00 2001
From: jaseg <git@jaseg.net>
Date: Sat, 6 Jul 2019 15:47:01 +0900
Subject: Add switch gpio, improve sleep scheduling

---
 main.c | 53 ++++++++++++++++++++++++++++-------------------------
 1 file changed, 28 insertions(+), 25 deletions(-)

diff --git a/main.c b/main.c
index 39f5452..2502be5 100644
--- a/main.c
+++ b/main.c
@@ -93,18 +93,6 @@ void rtc_set_alarm_rel_sec(uint32_t value) {
     rtc_set_alarm_sec(rtc_time() + value);
 }
 
-void switch_output_enable() {
-    uint32_t now = rtc_time();
-    if (now/300 % 24 == 0)
-        GPIOC->ODR |= 1<<14;
-    else
-        GPIOC->ODR &= ~(1<<14);
-}
-
-void switch_output_disable() {
-    GPIOC->ODR &= ~(1<<14);
-}
-
 int main(void){
     /* We're starting out from HSI@8MHz */
     SystemCoreClockUpdate();
@@ -115,8 +103,7 @@ int main(void){
     /* Turn on lots of neat things */
     RCC->APB2ENR |= RCC_APB2ENR_IOPCEN;
     RCC->APB1ENR |= RCC_APB1ENR_BKPEN | RCC_APB1ENR_PWREN;
-    PWR->CR = PWR_CR_PDDS | PWR_CR_DBP;
-    SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk; /* Use deep sleep mode */
+    PWR->CR = PWR_CR_DBP;
 
     GPIOC->CRH |=
           (0<<GPIO_CRH_CNF13_Pos) | (2<<GPIO_CRH_MODE13_Pos)| /* PC13 - LED */
@@ -131,23 +118,39 @@ int main(void){
     if (!(PWR->CSR & PWR_CSR_WUF)) /* This reset wasn't caused by the RTC alarm */
         REBOOT_REGISTER++;
 
+    uint32_t now = rtc_time();
+    bool switch_on = false;
     if (REBOOT_REGISTER > 1) { /* We have rebooted since initial bring-up */
         /* Give status indication and active output as fail-safe */
-        GPIOC->ODR &= ~(1<<13);
-        for (int i=0; i<5000; i++)
-            asm volatile ("nop");
-        GPIOC->ODR |= 1<<13;
+        if ((now&3) == 0) {
+            GPIOC->ODR &= ~(1<<13);
+            for (int i=0; i<5000; i++)
+                asm volatile ("nop");
+            GPIOC->ODR |= 1<<13;
+        }
+
+        switch_on = true;
 
-        switch_output_enable();
     } else {
-        uint32_t now = rtc_time();
-        if (now >= TARGET_DATE - (DAY_SECONDS*24) && now < TARGET_DATE)
-            switch_output_enable();
-        else
-            switch_output_disable();
+        switch_on = (now >= TARGET_DATE - (DAY_SECONDS*24) && now < TARGET_DATE);
+    }
+
+    if (switch_on && now/300 % 24 == 0) {
+        GPIOC->ODR |= 1<<14;
+
+        /* Go to sleep mode to keep GPIO active */
+        PWR->CR &= ~PWR_CR_PDDS;
+        SCB->SCR &= ~(SCB_SCR_SLEEPDEEP_Msk); /* Use deep sleep mode */
+
+    } else {
+        GPIOC->ODR &= ~(1<<14);
+
+        /* Go to standby mode to reduce power consumption */
+        PWR->CR = PWR_CR_PDDS;
+        SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk; /* Use deep sleep mode */
     }
 
-    PWR->CR |= PWR_CR_CWUF;
+    PWR->CR |= PWR_CR_CWUF; /* This has 2 cycles latency, thus the NOPs */
     asm volatile ("nop");
     asm volatile ("nop");
     asm volatile ("wfe");
-- 
cgit