nicla-system: Increase safety charge time from 3 to 9 hours.

Author: sebromero

libraries/Nicla_System/src/Nicla_System.cpp

@@ -150,6 +150,13 @@ bool nicla::enableCharging(uint16_t mA)
   // Also sets the input current limit to 350mA.
   _pmic.writeByte(BQ25120A_ADDRESS, BQ25120A_ILIM_UVLO_CTRL, 0x3F);
 
+  // Set safety timer to 9 hours (Bit 1+2 0b10) to give the battery enough of time to charge.
+  // Set it to 0b11 to disable safety timers. See: Table 24 in the datasheet.
+  uint8_t dpmTimerRegisterData = _pmic.readByte(BQ25120A_ADDRESS, BQ25120A_VIN_DPM);  
+  dpmTimerRegisterData |= 0b00000100; // Set Bit 2 to 1
+  dpmTimerRegisterData &= 0b11111101; // Set Bit 1 to 0  
+  _pmic.writeByte(BQ25120A_ADDRESS, BQ25120A_VIN_DPM, dpmTimerRegisterData);
+
   return _pmic.getFastChargeControlRegister() == _fastChargeRegisterData;
 }