Add a rough-and-ready and possibly working battery voltage reader.

davidgiven · davidgiven · commit 578c4fcf5b4b · 2024-06-04T22:02:11.000+02:00
diff --git a/ports/tc32/modtc32.c b/ports/tc32/modtc32.c
@@ -25,13 +25,45 @@
  */
 
 #include "modtc32.h"
+#include "machine_pin.h"
 #include "py/mphal.h"
 #include "py/runtime.h"
 
+#define BATTERY_SAMPLE_NUM 8
+static mp_obj_t tc32_battery_mv(void) {
+  static bool adc_hw_initialized = 0;
+  if (!adc_hw_initialized) {
+    adc_hw_initialized = 1;
+    adc_init();
+  }
+
+  adc_set_misc_rns_capture_state_length(0xf0); // max_mc
+  adc_set_all_set_state_length(0x0a);          // max_s
+
+  adc_set_chn_en(ADC_MISC_CHN);
+  adc_set_max_state_cnt(0x02);
+
+  adc_set_all_vref(ADC_MISC_CHN, ADC_VREF_1P2V);
+  adc_set_vref_vbat_div(ADC_VBAT_DIVIDER_OFF);
+
+  adc_set_misc_n_ain(GND);
+  adc_set_misc_p_ain(VBAT);
+  adc_set_misc_input_mode(DIFFERENTIAL_MODE);
+
+  adc_set_all_resolution(ADC_MISC_CHN, RES14);
+  adc_set_all_tsample_cycle(ADC_MISC_CHN, SAMPLING_CYCLES_6);
+  adc_set_all_ain_pre_scaler(ADC_PRESCALER_1F4);
+  adc_set_mode(ADC_NORMAL_MODE);
+
+  return MP_OBJ_NEW_SMALL_INT(adc_set_sample_and_get_result());
+}
+static MP_DEFINE_CONST_FUN_OBJ_0(tc32_battery_mv_obj, tc32_battery_mv);
+
 static const mp_rom_map_elem_t tc32_module_globals_table[] = {
     {MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_tc32)},
     {MP_ROM_QSTR(MP_QSTR_Flash), MP_ROM_PTR(&tc32_flash_type)},
     {MP_ROM_QSTR(MP_QSTR_Screen), MP_ROM_PTR(&tc32_screen_type)},
+    {MP_ROM_QSTR(MP_QSTR_battery_mv), MP_ROM_PTR(&tc32_battery_mv_obj)},
 };
 static MP_DEFINE_CONST_DICT(tc32_module_globals, tc32_module_globals_table);
 
diff --git a/ports/tc32/modtc32.h b/ports/tc32/modtc32.h
@@ -26,6 +26,7 @@
 #ifndef MICROPY_INCLUDED_TC32_MODTC32_H
 #define MICROPY_INCLUDED_TC32_MODTC32_H
 
+#include "port.h"
 #include "py/obj.h"
 
 extern const mp_obj_type_t tc32_flash_type;
