nrf5/hal: Updating hal_adc* with more api functions.

nrf5/hal/hal_adc.c

@@ -24,12 +24,121 @@
  * THE SOFTWARE.
  */
 
+#include <stdio.h>
 #include "mphalport.h"
 #include "hal_adc.h"
 
 #ifdef HAL_ADC_MODULE_ENABLED
 
+#define ADC_REF_VOLTAGE_IN_MILLIVOLTS  (1200) // Reference voltage (in milli volts) used by ADC while doing conversion.
+#define ADC_PRE_SCALING_COMPENSATION   (3)    // The ADC is configured to use VDD with 1/3 prescaling as input. And hence the result of conversion is to be multiplied by 3 to get the actual value of the battery voltage.
+#define DIODE_FWD_VOLT_DROP_MILLIVOLTS (270)  // Typical forward voltage drop of the diode (Part no: SD103ATW-7-F) that is connected in series with the voltage supply. This is the voltage drop when the forward current is 1mA. Source: Data sheet of 'SURFACE MOUNT SCHOTTKY BARRIER DIODE ARRAY' available at www.diodes.com.
+
+#define ADC_RESULT_IN_MILLI_VOLTS(ADC_VALUE)\
+        ((((ADC_VALUE) * ADC_REF_VOLTAGE_IN_MILLIVOLTS) / 255) * ADC_PRE_SCALING_COMPENSATION)
+
+static const uint32_t hal_adc_input_lookup[] = {
+    ADC_CONFIG_PSEL_AnalogInput0 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput1 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput2 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput3 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput4 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput5 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput6 << ADC_CONFIG_PSEL_Pos,
+    ADC_CONFIG_PSEL_AnalogInput7 << ADC_CONFIG_PSEL_Pos
+};
+
+
+static uint8_t battery_level_in_percent(const uint16_t mvolts)
+{
+    uint8_t battery_level;
+
+    if (mvolts >= 3000) {
+        battery_level = 100;
+    } else if (mvolts > 2900) {
+        battery_level = 100 - ((3000 - mvolts) * 58) / 100;
+    } else if (mvolts > 2740) {
+        battery_level = 42 - ((2900 - mvolts) * 24) / 160;
+    } else if (mvolts > 2440) {
+        battery_level = 18 - ((2740 - mvolts) * 12) / 300;
+    } else if (mvolts > 2100) {
+        battery_level = 6 - ((2440 - mvolts) * 6) / 340;
+    } else {
+        battery_level = 0;
+    }
+
+    return battery_level;
+}
+
+
 void hal_adc_init(HAL_ADC_Type * p_instance, hal_adc_init_t const * p_adc_init) {
+
+    while (p_instance->ENABLE && p_instance->BUSY)
+    {
+        // spin loop if another user is in progress of sampling
+    }
+
+    p_instance->INTENSET   = ADC_INTENSET_END_Msk;
+    p_instance->CONFIG     = (ADC_CONFIG_RES_8bit << ADC_CONFIG_RES_Pos)
+                           | (ADC_CONFIG_INPSEL_AnalogInputTwoThirdsPrescaling << ADC_CONFIG_INPSEL_Pos)
+                           | (ADC_CONFIG_REFSEL_VBG << ADC_CONFIG_REFSEL_Pos)
+                           | (hal_adc_input_lookup[p_adc_init->channel])
+                           | (ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos);
+}
+
+void hal_adc_start(HAL_ADC_Type * p_instance) {
+    p_instance->ENABLE = ADC_ENABLE_ENABLE_Enabled;
+}
+
+void hal_adc_stop(HAL_ADC_Type * p_instance) {
+    p_instance->ENABLE = ADC_ENABLE_ENABLE_Disabled;
+}
+
+uint8_t hal_adc_value(HAL_ADC_Type * p_instance) {
+
+    p_instance->EVENTS_END = 0;
+    p_instance->TASKS_START = 1;
+
+    while (!p_instance->EVENTS_END) {
+        ;
+    }
+
+    uint8_t adc_result = p_instance->RESULT;
+
+    p_instance->EVENTS_END = 0;
+    p_instance->TASKS_STOP = 1;
+
+    return adc_result;
+}
+
+uint8_t hal_adc_battery_level(HAL_ADC_Type * p_instance) {
+    p_instance->INTENSET   = ADC_INTENSET_END_Msk;
+    p_instance->CONFIG     = (ADC_CONFIG_RES_8bit                        << ADC_CONFIG_RES_Pos)
+                           | (ADC_CONFIG_INPSEL_SupplyOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos)
+                           | (ADC_CONFIG_REFSEL_VBG                      << ADC_CONFIG_REFSEL_Pos)
+                           | (ADC_CONFIG_PSEL_Disabled                   << ADC_CONFIG_PSEL_Pos)
+                           | (ADC_CONFIG_EXTREFSEL_None                  << ADC_CONFIG_EXTREFSEL_Pos);
+
+    p_instance->EVENTS_END  = 0;
+    p_instance->ENABLE      = ADC_ENABLE_ENABLE_Enabled;
+
+    p_instance->EVENTS_END  = 0;
+    p_instance->TASKS_START = 1;
+
+    while (!p_instance->EVENTS_END) {
+        ;
+    }
+
+    uint8_t  adc_result;
+    uint16_t batt_lvl_in_milli_volts;
+
+    p_instance->EVENTS_END = 0;
+    adc_result             = p_instance->RESULT;
+    p_instance->TASKS_STOP = 1;
+
+    batt_lvl_in_milli_volts = ADC_RESULT_IN_MILLI_VOLTS(adc_result) + DIODE_FWD_VOLT_DROP_MILLIVOLTS;
+    return battery_level_in_percent(batt_lvl_in_milli_volts);
+
 }
 
 #endif // HAL_ADC_MODULE_ENABLED

nrf5/hal/hal_adc.h

@@ -27,26 +27,38 @@
 #ifndef HAL_ADC_H__
 #define HAL_ADC_H__
 
+#include <stdint.h>
+
 #include "nrf.h"
 
 #if NRF51
 
 #define ADC_IRQ_NUM ADC_IRQn
-#define ADC_BASE(x) ((NRF_ADC_Type *)NRF_ADC_BASE)
+#define ADC_BASE ((NRF_ADC_Type *)NRF_ADC_BASE)
 #define HAL_ADC_Type NRF_ADC_Type
 
 #else
 
 #define ADC_IRQ_NUM SAADC_IRQn
-#define ADC_BASE(x) ((NRF_SAADC_Type *)NRF_SAADC_BASE)
+#define ADC_BASE ((NRF_SAADC_Type *)NRF_SAADC_BASE)
 #define HAL_ADC_Type NRF_SAADC_Type
 
 #endif
 
+typedef enum {
+    HAL_ADC_CHANNEL_2 = 2,
+    HAL_ADC_CHANNEL_3,
+    HAL_ADC_CHANNEL_4,
+    HAL_ADC_CHANNEL_5,
+    HAL_ADC_CHANNEL_6,
+    HAL_ADC_CHANNEL_7,
+} hal_adc_channel_t;
+
 /**
   * @brief  ADC Configuration Structure definition
   */
 typedef struct {
+    hal_adc_channel_t channel;
 } hal_adc_init_t;
 
 /**
@@ -60,4 +72,12 @@ typedef struct __ADC_HandleTypeDef
 
 void hal_adc_init(HAL_ADC_Type * p_instance, hal_adc_init_t const * p_adc_init);
 
+void hal_adc_start(HAL_ADC_Type * p_instance);
+
+void hal_adc_stop(HAL_ADC_Type * p_instance);
+
+uint8_t hal_adc_value(HAL_ADC_Type * p_instance);
+
+uint8_t hal_adc_battery_level(HAL_ADC_Type * p_instance);
+
 #endif // HAL_ADC_H__

nrf5/hal/hal_adce.c

@@ -32,4 +32,18 @@
 void hal_adc_init(HAL_ADC_Type * p_instance, hal_adc_init_t const * p_adc_init) {
 }
 
+void hal_adc_start(HAL_ADC_Type * p_instance) {
+}
+
+void hal_adc_stop(HAL_ADC_Type * p_instance) {
+}
+
+uint8_t hal_adc_value(HAL_ADC_Type * p_instance) {
+    return 0;
+}
+
+uint8_t hal_adc_battery_level(HAL_ADC_Type * p_instance) {
+    return 0;
+}
+
 #endif // HAL_ADCE_MODULE_ENABLED