LTC6813 aux channels are configured wrong (data for GPIO9, VREF2 and UVOV flags are never read)

[gudnimg]

I would think that:

ic[cic].ic_reg.aux_channels=9; // LTC6813

Should be:

ic[cic].ic_reg.aux_channels=12; // LTC6813

Because

• a_codes[0] = GPIO1
• a_codes[1] = GPIO2
• a_codes[2] = GPIO3
• a_codes[3] = GPIO4
• a_codes[4] = GPIO5
• a_codes[5] = VREF2
• a_codes[6] = GPIO6
• a_codes[7] = GPIO7
• a_codes[8] = GPIO8
• a_codes[9] = GPIO9
• a_codes[10] = Reserved
• a_codes[11] = UVOV flags for C13 to C18

This is how a_codes is defined in LTC681x.h

/*! AUX Reg Voltage Data structure */
typedef struct
{
  uint16_t a_codes[9]; //!< Aux Voltage Codes
  uint8_t pec_match[4]; //!< If a PEC error was detected during most recent read cmd
} ax;

This contradicts the example code from DC2350AB. I would expect a overflow when i > 8, was this code ever tested?

void print_aux(uint8_t datalog_en)
{
  for (int current_ic =0 ; current_ic < TOTAL_IC; current_ic++)
  {
    if (datalog_en == 0)
    {
      Serial.print(" IC ");
      Serial.print(current_ic+1,DEC);
      for (int i=0; i < 5; i++)
      {
        Serial.print(F(" GPIO-"));
        Serial.print(i+1,DEC);
        Serial.print(":");
        Serial.print(BMS_IC[current_ic].aux.a_codes[i]*0.0001,4);
        Serial.print(",");
      }

      for (int i=6; i < 10; i++)
      {
        Serial.print(F(" GPIO-"));
        Serial.print(i,DEC);
        Serial.print(":");
        Serial.print(BMS_IC[current_ic].aux.a_codes[i]*0.0001,4);        
      }

      Serial.print(F(" Vref2"));
      Serial.print(":");
      Serial.print(BMS_IC[current_ic].aux.a_codes[5]*0.0001,4);
      Serial.println();

      Serial.print(" OV/UV Flags : 0x");
      Serial.print((uint8_t)BMS_IC[current_ic].aux.a_codes[11],HEX);
      Serial.println();
    }
    else
    {
      Serial.print(" AUX, ");

      for (int i=0; i < 12; i++)
      {
        Serial.print((uint8_t)BMS_IC[current_ic].aux.a_codes[i]*0.0001,4);
        Serial.print(",");
      }
    }
  }
 Serial.println("\n");
}

[hugoquiroz]

@GunZi200 I ran across similar issue. with this register. I was attempting to read GPIO6 but based on how struct is aligned/written I was getting VREF2. My simple fix for this was changing

/*! AUX Reg Voltage Data structure */
typedef struct
{
  uint16_t a_codes[9]; //!< Aux Voltage Codes
  uint8_t pec_match[4]; //!< If a PEC error was detected during most recent read cmd
} ax;

to

/*! AUX Reg Voltage Data structure */
typedef struct
{
  uint16_t a_codes[12]; //!< Aux Voltage Codes
  uint8_t pec_match[4]; //!< If a PEC error was detected during most recent read cmd
} ax;