Battery Voltage

Readout/monitor battery voltage and turn off in case it gets too low. Also make the voltage available via API.

Partly implements #34.

lib/sdk/Libraries/CMSIS/Device/Maxim/MAX32665/Include/adc_regs.h

@@ -122,6 +122,9 @@ typedef struct {
  #define MXC_F_ADC_CTRL_REFBUF_PWR_POS                  3 /**< CTRL_REFBUF_PWR Position */
  #define MXC_F_ADC_CTRL_REFBUF_PWR                      ((uint32_t)(0x1UL << MXC_F_ADC_CTRL_REFBUF_PWR_POS)) /**< CTRL_REFBUF_PWR Mask */
 
+#define MXC_F_ADC_CTRL_CHGPUMP_PWR_POS                 4 /**< CTRL_CHGPUMP_PWR Position */
+#define MXC_F_ADC_CTRL_CHGPUMP_PWR                     ((uint32_t)(0x1UL << MXC_F_ADC_CTRL_CHGPUMP_PWR_POS)) /**< CTRL_CHGPUMP_PWR Mask */
+
  #define MXC_F_ADC_CTRL_REF_SEL_POS                     4 /**< CTRL_REF_SEL Position */
  #define MXC_F_ADC_CTRL_REF_SEL                         ((uint32_t)(0x1UL << MXC_F_ADC_CTRL_REF_SEL_POS)) /**< CTRL_REF_SEL Mask */