improvements to semestralka 2

semestralka_2/src/sleep/standby.rs

@@ -12,12 +12,17 @@ pub fn enter_standby() -> ! {
     cortex_m::asm::udf(); // never happen marker
 }
 
-pub fn enter_standby_with_sram2_retention() -> ! {
-    sram2_retention();
+pub fn enter_standby_with_sram2_8kb() -> ! {
+    sram2_8kb_retention();
     enter_standby();
 }
 
-pub fn sram2_retention() {
+pub fn enter_standby_with_sram2_full() -> ! {
+    sram2_full_retention();
+    enter_standby();
+}
+
+pub fn sram2_full_retention() {
     unsafe extern "C" {
         fn HAL_PWREx_EnableSRAM2ContentStandbyRetention(sram2_pages: u32);
     }
@@ -25,18 +30,29 @@ pub fn sram2_retention() {
     unsafe {
         // 0x60 = PWR_SRAM2_FULL_STANDBY = PWR_CR1_RRSB1 | PWR_CR1_RRSB2
         // See: STM32U5xx HAL: stm32u5xx_hal_pwr_ex.h line 227
-        //      CMSIS: PWR_CR1_RRSB1=0x20, PWR_CR1_RRSB2=0x40
+        // PWR_CR1_RRSB1=0x20, PWR_CR1_RRSB2=0x40
         HAL_PWREx_EnableSRAM2ContentStandbyRetention(0x60);
     }
 }
 
-pub fn disable_sram2_retention() {
+pub fn sram2_8kb_retention() {
+    unsafe extern "C" {
+        fn HAL_PWREx_EnableSRAM2ContentStandbyRetention(sram2_pages: u32);
+    }
+
+    unsafe {
+        // 0x40 = PWR_SRAM2_PAGE1_STANDBY = PWR_CR1_RRSB2
+        // 8KB retention only
+        HAL_PWREx_EnableSRAM2ContentStandbyRetention(0x40);
+    }
+}
+
+pub fn disable_sram2_full_retention() {
     unsafe extern "C" {
         fn HAL_PWREx_DisableSRAM2ContentStandbyRetention(sram2_pages: u32);
     }
 
     unsafe {
-        // Disable full SRAM2 retention
         HAL_PWREx_DisableSRAM2ContentStandbyRetention(0x60);
     }
 }