Implemented ADC gem.

Signed-off-by: Yilin Sun <imi415@imi.moe>

README.md

@@ -3,9 +3,9 @@
 ## Implemented features:
 ```ruby
 # Initialization: Takes a hash with configuration.
-led_red   = Machine::GPIO.new({pin: 38, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
-led_blue  = Machine::GPIO.new({pin: 36, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
-led_green = Machine::GPIO.new({pin: 39, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
+led_red   = Machine::GPIO.new(38, {mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
+led_blue  = Machine::GPIO.new(36, {mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
+led_green = Machine::GPIO.new(39, {mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
 ```
 
 ```ruby
@@ -16,3 +16,7 @@ led_red.on # Turn off the LED (Level is reversed)
 led_red.toggle # Toggle output
 ```
 
+```ruby
+ana_bg = Machine::ADC.new(52) # BandGap
+ana_bg.value
+```

lib/mruby

@@ -1 +1 @@
-Subproject commit 7f0aca015ec2bcad7d08d912163f135bdb238149
+Subproject commit 6be5185d38c88b22a9681f4937d47d568651ab73

src/mrb_machine_impl/mrb_machine_adc_impl.c

@@ -18,15 +18,39 @@
 /* Gem private */
 #include "machine-adc/src/adc.h"
 
+#define ADC_IMPL_CHANNEL_ID(x)        (x / 4)
+#define ADC_IMPL_CHANNEL_MODE(x)      (x % 4) /*  */
+#define ADC_IMPL_CHANNEL_REQUIRE_A(x) (((x % 4) != 1) ? true : false)
+#define ADC_IMPL_CHANNEL_REQUIRE_B(x) (((x % 4) != 0) ? true : false)
+
+#define ADC_IMPL_VREF_UV         3300000
+#define ADC_IMPL_FULL_SCALE      65536
+#define ADC_IMPL_FULL_SCALE_DIFF (ADC_IMPL_FULL_SCALE / 2)
+
 #define ADC_IMPL_PORT(x) (x / 32)
 #define ADC_IMPL_PIN(x)  (x % 32)
 
-#define ADC_EXT_CHANNEL_COUNT 10
-#define ADC_TEMP_CHANNEL      26
+#define ADC_EXT_CHANNEL_COUNT 5
+
+/**
+ * Channel Allocation
+ *  0,  1,  2,  3: CH0A, CH0B, CH0DIFF, CH0AB(Not supported)
+ *  4,  5,  6,  7: CH1A, CH1B, CH1DIFF, CH1AB(Not supported)
+ *  8,  9, 10, 11: CH2A, CH2B, CH2DIFF, CH2AB(Not supported)
+ * 12, 13, 14, 15: CH3A, CH3B, CH3DIFF, CH3AB(Not supported)
+ * 16, 17, 18, 19: CH4A, CH4B, CH4DIFF, CH4AB(Not supported)
+ * 48: VDDA
+ * 52: BIAS_VREF_1V
+ * 106: TEMP_SENSOR
+ */
 
 /* CH0A, CH0B, CH1A, CH1B, ... CH4A, CH4B */
-const static uint32_t s_adc_pin_table[ADC_EXT_CHANNEL_COUNT] = {
-    23, 16, 10, 11, 15, 12, 31, 32, 40, 41,
+const static uint32_t s_adc_pin_table_a[ADC_EXT_CHANNEL_COUNT] = {
+    23, 10, 15, 31, 40,
+};
+
+const static uint32_t s_adc_pin_table_b[ADC_EXT_CHANNEL_COUNT] = {
+    16, 11, 12, 32, 41,
 };
 
 static bool              s_adc_initialized = false;
@@ -51,9 +75,11 @@ static void mrb_machine_adc_impl_init_peripheral(void) {
     LPADC_Init(ADC0, &adc_cfg);
     LPADC_DoOffsetCalibration(ADC0);
     LPADC_DoAutoCalibration(ADC0);
+
+    NVIC_SetPriority(ADC0_IRQn, 5);
 }
 
-int mrb_machine_adc_impl_config(uint32_t pin) {
+int mrb_machine_adc_impl_config(uint32_t channel) {
     if (!s_adc_initialized) {
         mrb_machine_adc_impl_init_peripheral();
 
@@ -68,14 +94,28 @@ int mrb_machine_adc_impl_config(uint32_t pin) {
     uint32_t iocon_mode = IOCON_PIO_ASW(1);
 
     /* Configure IOCON only if this is an external channel */
-    if (pin < ADC_EXT_CHANNEL_COUNT) {
-        IOCON_PinMuxSet(IOCON, ADC_IMPL_PORT(s_adc_pin_table[pin]), ADC_IMPL_PIN(s_adc_pin_table[pin]), iocon_mode);
-    }
+    if (ADC_IMPL_CHANNEL_ID(channel) < ADC_EXT_CHANNEL_COUNT) {
+        uint32_t iocon_port;
+        uint32_t iocon_pin;
 
+        if (ADC_IMPL_CHANNEL_REQUIRE_A(channel)) {
+            iocon_port = ADC_IMPL_PORT(s_adc_pin_table_a[ADC_IMPL_CHANNEL_ID(channel)]);
+            iocon_pin  = ADC_IMPL_PIN(s_adc_pin_table_a[ADC_IMPL_CHANNEL_ID(channel)]);
+
+            IOCON_PinMuxSet(IOCON, iocon_port, iocon_pin, iocon_mode);
+        }
+
+        if (ADC_IMPL_CHANNEL_REQUIRE_B(channel)) {
+            iocon_port = ADC_IMPL_PORT(s_adc_pin_table_b[ADC_IMPL_CHANNEL_ID(channel)]);
+            iocon_pin  = ADC_IMPL_PIN(s_adc_pin_table_b[ADC_IMPL_CHANNEL_ID(channel)]);
+
+            IOCON_PinMuxSet(IOCON, iocon_port, iocon_pin, iocon_mode);
+        }
+    }
     return 0;
 }
 
-int mrb_machine_adc_impl_read(uint32_t pin) {
+int mrb_machine_adc_impl_read(uint32_t channel) {
     lpadc_conv_command_config_t conv_cfg;
     lpadc_conv_trigger_config_t trig_cfg;
 
@@ -84,41 +124,53 @@ int mrb_machine_adc_impl_read(uint32_t pin) {
 
     conv_cfg.conversionResolutionMode = kLPADC_ConversionResolutionHigh;
 
-    if (pin < ADC_EXT_CHANNEL_COUNT) {
-        /* This is an external channel, Positive and negative pair shares the same channel */
-
-        lpadc_sample_channel_mode_t mode;
-        if ((pin % 2) == 0) {
-            mode = kLPADC_SampleChannelSingleEndSideA;
-        } else {
-            mode = kLPADC_SampleChannelSingleEndSideB;
-        }
-
-        conv_cfg.channelNumber     = pin / 2;
-        conv_cfg.sampleChannelMode = mode;
-    } else if (pin == ADC_TEMP_CHANNEL) { /* Temperature channel requires differential sampling */
-        conv_cfg.channelNumber     = pin;
-        conv_cfg.sampleChannelMode = kLPADC_SampleChannelDiffBothSide;
-    } else { /* Other internal channels */
-        conv_cfg.channelNumber     = pin;
-        conv_cfg.sampleChannelMode = kLPADC_SampleChannelSingleEndSideA;
-    }
+    conv_cfg.channelNumber     = ADC_IMPL_CHANNEL_ID(channel);
+    conv_cfg.sampleChannelMode = ADC_IMPL_CHANNEL_MODE(channel);
 
     trig_cfg.targetCommandId       = 15;
     trig_cfg.enableHardwareTrigger = false;
+    trig_cfg.channelAFIFOSelect    = 0U;
+    trig_cfg.channelBFIFOSelect    = 0U;
 
     LPADC_SetConvCommandConfig(ADC0, 15, &conv_cfg);
     LPADC_SetConvTriggerConfig(ADC0, 0U, &trig_cfg);
 
+    /* Wait for 2 data if 2 channels are being sampled. */
+    if (ADC_IMPL_CHANNEL_MODE(channel) == kLPADC_SampleChannelDualSingleEndBothSide) {
+        ADC0->FCTRL[0] = ADC_FCTRL_FWMARK(1);
+    } else {
+        ADC0->FCTRL[0] = ADC_FCTRL_FWMARK(0);
+    }
+
     LPADC_EnableInterrupts(ADC0, kLPADC_FIFO0WatermarkInterruptEnable);
     EnableIRQ(ADC0_IRQn);
 
-    return 0;
+    LPADC_DoSoftwareTrigger(ADC0, 1U);
+
+    if (xSemaphoreTake(s_adc_semaphore, pdMS_TO_TICKS(500)) != pdTRUE) {
+        return 0;
+    }
+
+    uint8_t result_count = LPADC_GetConvResultCount(ADC0, 0);
+
+    lpadc_conv_result_t rslt;
+
+    for (uint8_t i = 0; i < result_count; i++) {
+        LPADC_GetConvResult(ADC0, &rslt, 0);
+    }
+
+    if (ADC_IMPL_CHANNEL_MODE(channel) == kLPADC_SampleChannelDiffBothSide) {
+        return (int)((int64_t)(int16_t)rslt.convValue * ADC_IMPL_VREF_UV / ADC_IMPL_FULL_SCALE_DIFF);
+    }
+
+    return (int)((int64_t)rslt.convValue * ADC_IMPL_VREF_UV / ADC_IMPL_FULL_SCALE);
 }
 
 void ADC0_IRQHandler(void) {
     BaseType_t higher_priority_woken = pdFALSE;
 
+    DisableIRQ(ADC0_IRQn);
+
     xSemaphoreGiveFromISR(s_adc_semaphore, &higher_priority_woken);
 
     if (higher_priority_woken) {