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ble nano hid over gatt

Dependencies:   BLE_API mbed-dev nRF51822

BatteryLevel.h@42:2c3be8694896, 2016-08-27 (annotated)

Committer:
cho45
Date:
Sat Aug 27 08:43:53 2016 +0000
Revision:
42:2c3be8694896
Child:
44:916b70fd1c40
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Who changed what in which revision?

UserRevisionLine numberNew contents of line
cho45 42:2c3be8694896 1 class BatteryLevel {
cho45 42:2c3be8694896 2
cho45 42:2c3be8694896 3 public:
cho45 42:2c3be8694896 4 static const float BATTERY_MAX = 2.4;
cho45 42:2c3be8694896 5 static const float REFERNECE = 1.2;
cho45 42:2c3be8694896 6 static const float PRESCALE = 3;
cho45 42:2c3be8694896 7 static const float BATTERY_LOW = 2.0;
cho45 42:2c3be8694896 8
cho45 42:2c3be8694896 9 static uint8_t readBatteryPercentage(float voltage) {
cho45 42:2c3be8694896 10 uint16_t percentage = (voltage - BATTERY_LOW) / (BATTERY_MAX - BATTERY_LOW) * 100;
cho45 42:2c3be8694896 11 if (percentage > 100) percentage = 100;
cho45 42:2c3be8694896 12 return percentage;
cho45 42:2c3be8694896 13 }
cho45 42:2c3be8694896 14
cho45 42:2c3be8694896 15 static float readBatteryVoltage() {
cho45 42:2c3be8694896 16 NRF_ADC->ENABLE = ADC_ENABLE_ENABLE_Enabled;
cho45 42:2c3be8694896 17
cho45 42:2c3be8694896 18 // Use internal 1.2V reference for batteryInput
cho45 42:2c3be8694896 19 // 1/3 pre-scaled input and 1.2V internal band gap reference
cho45 42:2c3be8694896 20 // ref. mbed-src/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/analogin_api.c
cho45 42:2c3be8694896 21 NRF_ADC->CONFIG =
cho45 42:2c3be8694896 22 (ADC_CONFIG_RES_10bit << ADC_CONFIG_RES_Pos) |
cho45 42:2c3be8694896 23 // Use VDD 1/3 for input
cho45 42:2c3be8694896 24 (ADC_CONFIG_INPSEL_SupplyOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos) |
cho45 42:2c3be8694896 25 // Use internal band gap for reference
cho45 42:2c3be8694896 26 (ADC_CONFIG_REFSEL_VBG << ADC_CONFIG_REFSEL_Pos) |
cho45 42:2c3be8694896 27 (ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos);
cho45 42:2c3be8694896 28
cho45 42:2c3be8694896 29 // Start ADC
cho45 42:2c3be8694896 30 NRF_ADC->TASKS_START = 1;
cho45 42:2c3be8694896 31 while (((NRF_ADC->BUSY & ADC_BUSY_BUSY_Msk) >> ADC_BUSY_BUSY_Pos) == ADC_BUSY_BUSY_Busy) {
cho45 42:2c3be8694896 32 // busy loop
cho45 42:2c3be8694896 33 }
cho45 42:2c3be8694896 34
cho45 42:2c3be8694896 35 // Read ADC result
cho45 42:2c3be8694896 36 uint16_t raw10bit = static_cast<uint16_t>(NRF_ADC->RESULT);
cho45 42:2c3be8694896 37
cho45 42:2c3be8694896 38 NRF_ADC->ENABLE = ADC_ENABLE_ENABLE_Disabled;
cho45 42:2c3be8694896 39
cho45 42:2c3be8694896 40 float ratio = raw10bit / static_cast<float>(1<<10);
cho45 42:2c3be8694896 41
cho45 42:2c3be8694896 42 float batteryVoltage = ratio * (REFERNECE * PRESCALE);
cho45 42:2c3be8694896 43 return batteryVoltage;
cho45 42:2c3be8694896 44 }
cho45 42:2c3be8694896 45 };