rp2/machine_adc: Add support for external ADC channels.

Signed-off-by: iabdalkader <i.abdalkader@gmail.com>
micropython · Oct 20, 2023 · 5e52389 · 5e52389
1 parent 4358faa
commit 5e52389
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Showing 3 changed files with 43 additions and 6 deletions.
diff --git a/ports/rp2/machine_adc.c b/ports/rp2/machine_adc.c
@@ -27,6 +27,7 @@
 #include "py/runtime.h"
 #include "py/mphal.h"
 #include "hardware/adc.h"
+#include "machine_pin.h"
 
 #define ADC_IS_VALID_GPIO(gpio) ((gpio) >= 26 && (gpio) <= 29)
 #define ADC_CHANNEL_FROM_GPIO(gpio) ((gpio) - 26)
@@ -48,6 +49,9 @@ const mp_obj_type_t machine_adc_type;
 typedef struct _machine_adc_obj_t {
     mp_obj_base_t base;
     uint32_t channel;
+    #if MICROPY_HW_ADC_EXT_COUNT
+    uint32_t is_ext : 1;
+    #endif
 } machine_adc_obj_t;
 
 STATIC void machine_adc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
@@ -63,6 +67,9 @@ STATIC mp_obj_t machine_adc_make_new(const mp_obj_type_t *type, size_t n_args, s
     mp_obj_t source = all_args[0];
 
     uint32_t channel;
+    bool is_ext = false;
+    const machine_pin_obj_t *pin = NULL;
+
     if (mp_obj_is_int(source)) {
         // Get and validate channel number.
         channel = mp_obj_get_int(source);
@@ -72,18 +79,35 @@ STATIC mp_obj_t machine_adc_make_new(const mp_obj_type_t *type, size_t n_args, s
 
     } else {
         // Get GPIO and check it has ADC capabilities.
-        channel = mp_hal_get_pin_obj(source);
-        if (!ADC_IS_VALID_GPIO(channel)) {
+        pin = machine_pin_find(source);
+        channel = pin->id;
+        bool valid_adc_pin = false;
+        #if MICROPY_HW_ADC_EXT_COUNT
+        is_ext = pin->is_ext;
+        if (is_ext) {
+            valid_adc_pin = machine_pin_ext_is_adc_channel(pin);
+        } else
+        #endif
+        {
+            valid_adc_pin = ADC_IS_VALID_GPIO(channel);
+        }
+        if (!valid_adc_pin) {
             mp_raise_ValueError(MP_ERROR_TEXT("Pin doesn't have ADC capabilities"));
         }
     }
 
     // Initialise the ADC peripheral if it's not already running.
-    if (!(adc_hw->cs & ADC_CS_EN_BITS)) {
+    if (!is_ext && !(adc_hw->cs & ADC_CS_EN_BITS)) {
         adc_init();
     }
 
-    if (ADC_IS_VALID_GPIO(channel)) {
+    if (is_ext) {
+        #if MICROPY_HW_ADC_EXT_COUNT
+        // Note external pins are mutable.
+        machine_pin_ext_config((machine_pin_obj_t *)pin, MACHINE_PIN_MODE_ANALOG, 0);
+        channel = machine_pin_ext_to_adc_channel(pin);
+        #endif
+    } else if (ADC_IS_VALID_GPIO(channel)) {
         // Configure the GPIO pin in ADC mode.
         adc_gpio_init(channel);
         channel = ADC_CHANNEL_FROM_GPIO(channel);
@@ -95,13 +119,21 @@ STATIC mp_obj_t machine_adc_make_new(const mp_obj_type_t *type, size_t n_args, s
     // Create ADC object.
     machine_adc_obj_t *o = mp_obj_malloc(machine_adc_obj_t, &machine_adc_type);
     o->channel = channel;
+    #if MICROPY_HW_ADC_EXT_COUNT
+    o->is_ext = is_ext;
+    #endif
 
     return MP_OBJ_FROM_PTR(o);
 }
 
 // read_u16()
 STATIC mp_obj_t machine_adc_read_u16(mp_obj_t self_in) {
     machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    #if MICROPY_HW_ADC_EXT_COUNT
+    if (self->is_ext) {
+        return MP_OBJ_NEW_SMALL_INT(machine_pin_ext_read_u16(self->channel));
+    }
+    #endif
     return MP_OBJ_NEW_SMALL_INT(adc_config_and_read_u16(self->channel));
 }
 MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_read_u16_obj, machine_adc_read_u16);

diff --git a/ports/rp2/machine_pin.c b/ports/rp2/machine_pin.c
@@ -166,7 +166,7 @@ const machine_pin_af_obj_t *machine_pin_find_alt_by_index(const machine_pin_obj_
     return NULL;
 }
 
-static const machine_pin_obj_t *machine_pin_find(mp_obj_t pin) {
+const machine_pin_obj_t *machine_pin_find(mp_obj_t pin) {
     // Is already a object of the proper type
     if (mp_obj_is_type(pin, &machine_pin_type)) {
         return pin;

diff --git a/ports/rp2/machine_pin.h b/ports/rp2/machine_pin.h
@@ -34,7 +34,8 @@ enum {
     MACHINE_PIN_MODE_IN = 0,
     MACHINE_PIN_MODE_OUT = 1,
     MACHINE_PIN_MODE_OPEN_DRAIN = 2,
-    MACHINE_PIN_MODE_ALT = 3
+    MACHINE_PIN_MODE_ALT = 3,
+    MACHINE_PIN_MODE_ANALOG = 4
 };
 
 typedef struct _machine_pin_af_obj_t {
@@ -71,10 +72,14 @@ extern const mp_obj_type_t pin_board_pins_obj_type;
 extern const mp_obj_dict_t pin_board_pins_locals_dict;
 
 void machine_pin_ext_init(void);
+bool machine_pin_ext_is_adc_channel(const machine_pin_obj_t *self);
+uint32_t machine_pin_ext_to_adc_channel(const machine_pin_obj_t *self);
 void machine_pin_ext_set(machine_pin_obj_t *self, bool value);
 bool machine_pin_ext_get(machine_pin_obj_t *self);
+uint16_t machine_pin_ext_read_u16(uint32_t channel);
 void machine_pin_ext_config(machine_pin_obj_t *self, int mode, int value);
 
+const machine_pin_obj_t *machine_pin_find(mp_obj_t pin);
 const machine_pin_obj_t *machine_pin_find_named(const mp_obj_dict_t *named_pins, mp_obj_t name);
 const machine_pin_af_obj_t *machine_pin_find_alt(const machine_pin_obj_t *pin, uint8_t fn);
 const machine_pin_af_obj_t *machine_pin_find_alt_by_index(const machine_pin_obj_t *pin, mp_uint_t af_idx);