microbitv2: Don't calculate the power source in the USB insertion interrupt.

As it caused problems in the KL27 port with a timer interrupt being
set up to wait for 3 ms inside the USB insertion interrupt.

Sets the timer interrupt to level 2 (second lowest, but higher
than the wake up pin and USB insertion), as the default is
level 0, over other important interrupts like USB and I2C.

Also removes the need to check for the power source when the
Interface is requested to go to sleep, as it only really needs to
know if it's "USB connected" (being on battery or USB power bank
should have the same effect, it should not behave differently in
battery power vs USB power bank).

Author: microbit-carlos

source/board/microbitv2/i2c_commands.c

@@ -32,7 +32,6 @@
 
 
 extern uint16_t board_id_hex;
-extern power_source_t power_source;
 extern main_usb_connect_t usb_state;
 extern microbit_if_power_mode_t interface_power_mode;
 extern bool power_led_sleep_state_on;
@@ -77,10 +76,11 @@ static void i2c_write_comms_callback(uint8_t* pData, uint8_t size) {
                     memcpy(&i2cResponse.cmdData.readRspCmd.data, &daplink_version, sizeof(daplink_version));
                 }
                 break;
-                case gPowerState_c:
-                    power_source = pwr_mon_get_power_source();
+                case gPowerState_c: {
+                    power_source_t power_source = pwr_mon_get_power_source();
                     i2cResponse.cmdData.readRspCmd.dataSize = sizeof(power_source);
                     memcpy(&i2cResponse.cmdData.readRspCmd.data, &power_source, sizeof(power_source));
+                }
                 break;
                 case gPowerConsumption_c: {
                     uint32_t vin_voltage_uv = pwr_mon_get_vin_mv() * 1000;

source/board/microbitv2/kl27z/power.c

@@ -67,7 +67,6 @@ extern volatile uint8_t wake_from_reset;
 extern volatile uint8_t wake_from_usb;
 extern volatile bool usb_pc_connected;
 extern main_usb_connect_t usb_state;
-extern power_source_t power_source;
 
 /*******************************************************************************
  * Code
@@ -99,8 +98,6 @@ void PORTCD_IRQHandler(void)
     if ((1U << PIN_WAKE_ON_EDGE_BIT) & PORT_GetPinsInterruptFlags(PIN_WAKE_ON_EDGE_PORT))
     {
         PORT_ClearPinsInterruptFlags(PIN_WAKE_ON_EDGE_PORT, (1U << PIN_WAKE_ON_EDGE_BIT));
-        
-        power_source = pwr_mon_get_power_source();
 
         bool usb_on = (((PIN_WAKE_ON_EDGE_GPIO->PDIR) >> PIN_WAKE_ON_EDGE_BIT) & 0x01U) ? false : true;
 
@@ -138,6 +135,7 @@ void power_init(void)
     /* Enable either edge interrupt on WAKE_ON_EDGE pin to detect USB attach/detach */
     PORT_SetPinInterruptConfig(PIN_WAKE_ON_EDGE_PORT, PIN_WAKE_ON_EDGE_BIT, PIN_WAKE_ON_EDGE_PORT_WAKEUP_TYPE);
 
+    /* Enable IRQ and set priority to the lowest level */
     NVIC_SetPriority(LLWU_IRQn, (1UL << __NVIC_PRIO_BITS) - 1UL);
     NVIC_EnableIRQ(LLWU_IRQn);
     NVIC_SetPriority(PORTC_PORTD_IRQn, (1UL << __NVIC_PRIO_BITS) - 1UL);

source/board/microbitv2/kl27z/timer_wait.c

@@ -47,10 +47,15 @@ void timer_wait_init(void)
     TPM_GetDefaultConfig(&tpmInfo);
     /* TPM clock divide by TPM_PRESCALER */
     tpmInfo.prescale = kTPM_Prescale_Divide_4;
+    /* TPM counter starts immediately once it is enabled */
+    tpmInfo.enableStartOnTrigger = false;
     /* Initialize TPM module */
     TPM_Init(TPM0, &tpmInfo);
 
+    /* Enable interrupt and set it to second lowest priority level */
+    const uint32_t lowest_priority_level = (1UL << __NVIC_PRIO_BITS) - 1UL;
     TPM_EnableInterrupts(TPM0, kTPM_TimeOverflowInterruptEnable);
+    NVIC_SetPriority(TPM0_IRQn, lowest_priority_level - 1);
     EnableIRQ(TPM0_IRQn);
 
     tpm_source_clock = (CLOCK_GetFreq(kCLOCK_McgIrc48MClk) / 4);

source/board/microbitv2/microbitv2.c

@@ -57,7 +57,6 @@ extern target_cfg_t target_device_nrf52833;
 volatile uint8_t wake_from_reset = 0;
 volatile uint8_t wake_from_usb = 0;
 volatile bool usb_pc_connected = false;
-power_source_t power_source;
 microbit_if_power_mode_t interface_power_mode = MB_POWER_RUNNING;
 bool power_led_sleep_state_on = PWR_LED_SLEEP_STATE_DEFAULT;
 bool automatic_sleep_on = AUTOMATIC_SLEEP_DEFAULT;
@@ -125,15 +124,13 @@ static void prerun_board_config(void)
     power_init();
     pwr_mon_init();
 
-    power_source = pwr_mon_get_power_source();
-
     pwm_init();
     pwm_init_pins();
 
+    power_source_t power_source = pwr_mon_get_power_source();
     if (power_source == PWR_BATT_ONLY){
         // Turn on the red LED with low duty cycle to conserve power.
         power_led_max_duty_cycle = PWR_LED_ON_BATT_BRIGHTNESS;
-
     } else {
         // Turn on the red LED with max duty cycle when powered by USB or EC
         power_led_max_duty_cycle = PWR_LED_ON_MAX_BRIGHTNESS;
@@ -262,17 +259,10 @@ void board_30ms_hook()
           }
           break;
       case MAIN_SHUTDOWN_REQUESTED:
-          if (power_source == PWR_BATT_ONLY || (usb_state == USB_DISCONNECTED && !usb_pc_connected)) {
+          if (usb_state == USB_DISCONNECTED && !usb_pc_connected) {
               main_powerdown_event();
 
-              // In VLLS0, set the LED either ON or LOW, depending on power_led_sleep_state_on
-              // When the duty cycle is 0% or 100%, the FlexIO driver will configure the pin as GPIO
-              if (power_led_sleep_state_on == true && interface_power_mode == MB_POWER_DOWN) {
-                  shutdown_led_dc = PWR_LED_ON_MAX_BRIGHTNESS;
-              } else if (power_led_sleep_state_on == true && interface_power_mode == MB_POWER_SLEEP) {
-                  shutdown_led_dc = PWR_LED_ON_BATT_BRIGHTNESS;
-              }
-              else {
+              if (!power_led_sleep_state_on) {
                   shutdown_led_dc = 0;
               }
 

source/board/microbitv2/nrf52820/power.c

@@ -51,7 +51,6 @@ extern volatile uint8_t wake_from_reset;
 extern volatile uint8_t wake_from_usb;
 extern volatile bool usb_pc_connected;
 extern main_usb_connect_t usb_state;
-extern power_source_t power_source;
 
 
 uint8_t  power_gpiote_enabled;
@@ -242,8 +241,6 @@ void GPIOTE_IRQHandler(void)
 
             power_gpio_set_sense(reg, idx, absent ? NRF_GPIO_PIN_SENSE_LOW : NRF_GPIO_PIN_SENSE_HIGH);
 
-            power_source = pwr_mon_get_power_source();
-
             // Read VBUS_ABSENT (WAKE_ON_EDGE) pin for detecting if board is USB powered
             if (absent) {
                 /* Reset USB on cable detach (VBUS falling edge) */
@@ -266,13 +263,11 @@ void POWER_CLOCK_IRQHandler(void)
 {
     if (NRF_POWER->EVENTS_USBDETECTED) {
         NRF_POWER->EVENTS_USBDETECTED = 0;
-        power_source = pwr_mon_get_power_source();
         wake_from_usb = 1;
     }
 
     if (NRF_POWER->EVENTS_USBREMOVED) {
         NRF_POWER->EVENTS_USBREMOVED = 0;
-        power_source = pwr_mon_get_power_source();
         /* Reset USB on cable detach (VBUS falling edge) */
         USBD_Reset();
         usbd_reset_core();