nrf52/hal: Adding adce (saadc) implementation for nrf52 to sample values on a channel.

nrf5/hal/hal_adce.c

@@ -23,14 +23,92 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-
+#include <stdio.h>
 #include "mphalport.h"
 #include "hal_adc.h"
 
 #ifdef HAL_ADCE_MODULE_ENABLED
 
+static const uint32_t hal_adc_input_lookup_pos[] = {
+    SAADC_CH_PSELP_PSELP_AnalogInput0 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput1 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput2 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput3 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput4 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput5 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput6 << SAADC_CH_PSELP_PSELP_Pos,
+    SAADC_CH_PSELP_PSELP_AnalogInput7 << SAADC_CH_PSELP_PSELP_Pos
+};
+
+#define HAL_ADCE_PSELP_NOT_CONNECTED (SAADC_CH_PSELP_PSELP_NC << SAADC_CH_PSELP_PSELP_Pos)
+#define HAL_ADCE_PSELP_VDD           (SAADC_CH_PSELP_PSELP_VDD << SAADC_CH_PSELP_PSELP_Pos)
+
+static const uint32_t hal_adc_input_lookup_neg[] = {
+    SAADC_CH_PSELN_PSELN_AnalogInput0 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput1 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput2 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput3 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput4 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput5 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput6 << SAADC_CH_PSELN_PSELN_Pos,
+    SAADC_CH_PSELN_PSELN_AnalogInput7 << SAADC_CH_PSELN_PSELN_Pos
+};
+
+#define HAL_ADCE_PSELN_NOT_CONNECTED (SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos)
+#define HAL_ADCE_PSELN_VDD           (SAADC_CH_PSELN_PSELN_VDD << SAADC_CH_PSELN_PSELN_Pos)
+
 uint16_t hal_adc_channel_value(hal_adc_config_t const * p_adc_conf) {
-    return 0;
+    int16_t result = 0;
+
+    // configure to use VDD/4 and gain 1/4
+    ADC_BASE->CH[0].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_4  << SAADC_CH_CONFIG_GAIN_Pos)
+                           | (SAADC_CH_CONFIG_MODE_SE       << SAADC_CH_CONFIG_MODE_Pos)
+                           | (SAADC_CH_CONFIG_REFSEL_VDD1_4 << SAADC_CH_CONFIG_REFSEL_Pos)
+                           | (SAADC_CH_CONFIG_RESN_Bypass   << SAADC_CH_CONFIG_RESN_Pos)
+                           | (SAADC_CH_CONFIG_RESP_Bypass   << SAADC_CH_CONFIG_RESP_Pos)
+                           | (SAADC_CH_CONFIG_TACQ_3us      << SAADC_CH_CONFIG_TACQ_Pos);
+
+    // positive input
+    ADC_BASE->CH[0].PSELP = hal_adc_input_lookup_pos[p_adc_conf->channel]; // HAL_ADCE_PSELP_VDD;
+    ADC_BASE->CH[0].PSELN = HAL_ADCE_PSELN_NOT_CONNECTED;
+
+    ADC_BASE->RESOLUTION    = SAADC_RESOLUTION_VAL_8bit << SAADC_RESOLUTION_VAL_Pos;
+    ADC_BASE->RESULT.MAXCNT = 1;
+    ADC_BASE->RESULT.PTR    = (uint32_t)&result;
+    ADC_BASE->SAMPLERATE    = SAADC_SAMPLERATE_MODE_Task << SAADC_SAMPLERATE_MODE_Pos;
+    ADC_BASE->ENABLE        = SAADC_ENABLE_ENABLE_Enabled << SAADC_ENABLE_ENABLE_Pos;
+
+    // calibrate ADC
+    ADC_BASE->TASKS_CALIBRATEOFFSET = 1;
+    while (ADC_BASE->EVENTS_CALIBRATEDONE == 0) {
+        ;
+    }
+    ADC_BASE->EVENTS_CALIBRATEDONE = 0;
+    while (ADC_BASE->STATUS == (SAADC_STATUS_STATUS_Busy << SAADC_STATUS_STATUS_Pos)) {
+        ;
+    }
+
+    // start the ADC
+    ADC_BASE->TASKS_START = 1;
+    while (ADC_BASE->EVENTS_STARTED == 0) {
+        ;
+    }
+    ADC_BASE->EVENTS_STARTED = 0;
+
+    // sample ADC
+    ADC_BASE->TASKS_SAMPLE = 1;
+    while (ADC_BASE->EVENTS_END == 0) {
+        ;
+    }
+    ADC_BASE->EVENTS_END = 0;
+
+    ADC_BASE->TASKS_STOP = 1;
+    while (ADC_BASE->EVENTS_STOPPED == 0) {
+        ;
+    }
+    ADC_BASE->EVENTS_STOPPED = 0;
+
+    return result;
 }
 
 uint16_t hal_adc_battery_level(void) {