BQ76942EVM: SPI Interface problem with RL78/F13(R5F10BGE) Microcontroller

pankaj kumar2

Part Number: BQ76942EVM
Other Parts Discussed in Thread: BQ76942, BQSTUDIO, BQ76952

  


Functions and Variables used in our code to Reading Cell 1 voltage :-

//----Functions & Variable Declaration---------

uint8_t cell1_Volt_Lbyte_Txarr[3],cell1_Volt_Lbyte_Rxarr[3];
uint8_t cell1_Volt_Hbyte_Txarr[3],cell1_Volt_Hbyte_Rxarr[3];

bit Flag_Device_Reset,
Flag_Swap_To_Spi,
Flag_REG0_Config_Enable,
Flag_REG1_Config_Enable;


uint8_t SWAP_SPI_TxArr_L[2],SWAP_SPI_TxArr_H[2],SWAP_SPI_RxArr_L[2],SWAP_SPI_RxArr_H[2];

uint8_t Device_Reset_TxArr_L[2], 
Device_Reset_TxArr_H[2], 
Device_Reset_RxArr_L[2], 
Device_Reset_RxArr_H[2];

uint8_t REG0_TxCmdAdd_L[2],REG0_RxCmdAdd_L[2],
REG0_TxCmdAdd_H[2],REG0_RxCmdAdd_H[2],
REG0_TxDataAdd[1],REG0_RxDataAdd[1],
REG0_TxValue[1],REG0_RxValue[1];

uint8_t REG1_TxCmdAdd_L[2],REG1_RxCmdAdd_L[2],
REG1_TxCmdAdd_H[2],REG1_RxCmdAdd_H[2],
REG1_TxDataAdd[1],REG1_RxDataAdd[1],
REG1_TxValue[1],REG1_RxValue[1];

uint8_t Cell_1_Volt_Lbyte=0,Cell_1_Volt_Hbyte=0;

void ucSPI00_Read_Cell_1_Lbyte_Voltage(void);
void ucSPI00_Read_Cell_1_Hbyte_Voltage(void);
void SWAP_TO_SPI_Communication_Init(void);
void BQ76942_Device_Reset(void);
void REG0_Config_Enable(void);
void REG1_Config_Enable(void);



//---Calling of main function------------------------------

void main(void)
{
PIOR4 = 0x00U;
SELLOSC = 1U;
MDIV = 0x00;
SELPLL = 0U;;

CMC = 0x00; //X1 & X2 pins of oscillator as INPUT; port pins.
CKC = 0x00; //SELECT INTERNAL HIGH SPEED OSCILLATOR.
CSC = 0xC0; //EXTERNAL OSCILLATOR X1-X2 AND XT1-XT2 STOPPED,INTERNAL HIGH SPEED OSCILLATOR OPERATING.
HOCODIV = 0x00; //NO FREQUENCY DIVISION --- Bus Clock = 24MHz
CRC0CTL = 0x00;
IAWCTL = 0x00;

vMain_PowerOnInit();
EI();

//------------------------------------------------------------------------------- 
//---Date 03-12-2020 @ 016:51 PM 
//------Device Reset commmand=0x0012 
Device_Reset_TxArr_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
Device_Reset_TxArr_L[1]=0x12;//--Lower byte =0x12

Device_Reset_TxArr_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
Device_Reset_TxArr_H[1]=0x00;//--Higher Byte=0x00 
//----------------------------------------------------------------------------- 
//--SWAP TO SPI Command =0x7C35------- 
SWAP_SPI_TxArr_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
SWAP_SPI_TxArr_L[1]=0x35;//Lower Byte=0x35

SWAP_SPI_TxArr_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
SWAP_SPI_TxArr_H[1]=0x7C;//Higher Byte=0x7C
//-----------------------------------------------------------------------------
//---REG0 Config Enable : Address=0x921B, Data =0x01(REG0_EN bit =1)
//---Addres write(0x921B)
REG0_TxCmdAdd_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
REG0_TxCmdAdd_L[1]=0x1B;//Lower byte=0x1B

REG0_TxCmdAdd_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
REG0_TxCmdAdd_H[1]=0x92;//Higher byte=0x92

//--Data addr write at 0x40=0x01
REG0_TxDataAdd[0]=0xC0;//--(R/W bit=1 for Write)+0x40=0xC0(To write value @ 0x40)
//--Value write
REG0_TxValue[0]=0x01;//Data =0x01(REG0_EN bit =1)
//----------------------------------------------------------------------------- 
//--REG1=3.3V Enable : Address=0x921A, Data=0x0D(3.3 volt )[REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1] 
//---Addres write(0x921A)
REG1_TxCmdAdd_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
REG1_TxCmdAdd_L[1]=0x1A;//Lower byte=0x1A

REG1_TxCmdAdd_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
REG1_TxCmdAdd_H[1]=0x92;//Higher byte=0x92

//--Data addr write at 0x40=0x0D
REG1_TxDataAdd[0]=0xC0;//--(R/W bit=1 for Write)+0x40=0xC0(writing value @ 0x40)
//--Value write
REG1_TxValue[0]=0x0D;//--Data =0x0D(REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1)

//----------------------------------------------------------------------------- 
//--- cell 1 Lbyte Reading ----
cell1_Volt_Lbyte_Txarr[0]=0x14;//0x14 location Read
cell1_Volt_Lbyte_Txarr[1]=0xFF;

//---Cell 1 Hbyte Reading -----
cell1_Volt_Hbyte_Txarr[0]=0x15;//0x15 location Read
cell1_Volt_Hbyte_Txarr[1]=0xFF;


Flag_Device_Reset=1; 
Flag_Swap_To_Spi=1;
Flag_REG0_Config_Enable=1;
Flag_REG1_Config_Enable=1;

while(1)
{ //main while start 
//-----------------------------BQ76942 Device Initialization----------------------------------------------------------------------------- 
while(Flag_Device_Reset) //--Send Device Reset commmand-->>0x0012 till correct value return 
{
BQ76942_Device_Reset(); 

if((Device_Reset_TxArr_L[0]==Device_Reset_RxArr_L[0])&&(Device_Reset_TxArr_H[0]==Device_Reset_RxArr_H[0]))//Checking device reset 
Flag_Device_Reset=0;
}

while(Flag_Swap_To_Spi)//-Send SWAP to spi Communication command-->>0x7C35 till correct value returns
{
SWAP_TO_SPI_Communication_Init();

if((SWAP_SPI_TxArr_L[0]==SWAP_SPI_RxArr_L[0])&&(SWAP_SPI_TxArr_H[0]==SWAP_SPI_RxArr_H[0]))//Checking Device swaping to SPI
Flag_Swap_To_Spi=0;
}

while(Flag_REG0_Config_Enable) //Send REG0 Enable command-->>value=0x01(REG0_EN bit =1) at REG0 config at Address=0x921B
{
REG0_Config_Enable();

if((REG0_TxCmdAdd_L[0]==REG0_RxCmdAdd_L[0])&&(REG0_TxCmdAdd_H[0]==REG0_RxCmdAdd_H[0]))//Checking REG0 Enable command 
Flag_REG0_Config_Enable=0;
} 

while(Flag_REG1_Config_Enable)//Send REG1=3.3V Enable : Address=0x921A, Data=0x0D(3.3 volt )[REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1] 
{
REG1_Config_Enable();

if((REG1_TxCmdAdd_L[0]==REG1_RxCmdAdd_L[0])&&(REG1_TxCmdAdd_H[0]==REG1_RxCmdAdd_H[0]))//Checking REG1 Enable command 
Flag_REG1_Config_Enable=0;
} 
//----------------------------------------------------------------------------------------------------------------------------------
//----Cell 1 Voltage Reading at 0x14 and 0x15 location 
while(1) //--Continous reading of Cell 1 voltage Lower byte 
{ 
ucSPI00_Read_Cell_1_Lbyte_Voltage();// Read Cell_1 voltage lower byte----Send at MOSI (0x14 ,0xFF)

if(cell1_Volt_Lbyte_Txarr[0]==cell1_Volt_Lbyte_Rxarr[0])//Voltage read when (MOSI=0x14 and MISO=0x14)
{
Cell_1_Volt_Lbyte=cell1_Volt_Lbyte_Rxarr[1];
break;
} 
}

while(1)//--Continous reading of Cell 1 voltage Higher byte
{
ucSPI00_Read_Cell_1_Hbyte_Voltage();// Read Cell_1 voltage of Higher byte

if(cell1_Volt_Hbyte_Txarr[0]==cell1_Volt_Hbyte_Rxarr[0])//Voltage read when (MOSI=0x15 and MISO=0x15)
{
Cell_1_Volt_Hbyte=cell1_Volt_Hbyte_Rxarr[1];
break;
}
} 
//------------------------------------------------------------------------------------------------------------------------
}//main while end 
}

 





//----------------Function Definitions ------------------------------------------------------------------

void REG1_Config_Enable(void)
{
//---Enable REG1 Config: Write value=0x0D(REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1) at REG1 config Address=0x921A 

ucSPI00_ReadWriteData(1,(uint8_t*)&REG1_TxCmdAdd_L[0],1,(uint8_t*)&REG1_RxCmdAdd_L[0]); //Write command Addr=0xBE(W=1+0x3E ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&REG1_TxCmdAdd_L[1],1,(uint8_t*)&REG1_RxCmdAdd_L[1]); //Write REG0 LByte Addr=0x1A

ucSPI00_ReadWriteData(1,(uint8_t*)&REG1_TxCmdAdd_H[0],1,(uint8_t*)&REG1_RxCmdAdd_H[0]); //Write command Addr=0xBF(W=1+0x3F ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&REG1_TxCmdAdd_H[1],1,(uint8_t*)&REG1_RxCmdAdd_H[1]); //Write REG0 HByte Addr=0x92

ucSPI00_ReadWriteData(1,(uint8_t*)&REG1_TxDataAdd[0],1,(uint8_t*)&REG1_RxDataAdd[0]); //Write Data Addr=0xC0(W=1+0x40 ,write value @ 0x40) 
ucSPI00_ReadWriteData(1,(uint8_t*)&REG1_TxValue[0],1,(uint8_t*)&REG1_RxValue[0]); //Write value=0x0D (REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1) at 0xC0
}

void REG0_Config_Enable(void)
{
//---Enable REG0 Config: Write value=0x01(REG0_EN bit =1) at REG0 config Address=0x921B 

ucSPI00_ReadWriteData(1,(uint8_t*)&REG0_TxCmdAdd_L[0],1,(uint8_t*)&REG0_RxCmdAdd_L[0]); //Write command Addr=0xBE(W=1+0x3E ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&REG0_TxCmdAdd_L[1],1,(uint8_t*)&REG0_RxCmdAdd_L[1]); //Write REG0 LByte Addr=0x1B

ucSPI00_ReadWriteData(1,(uint8_t*)&REG0_TxCmdAdd_H[0],1,(uint8_t*)&REG0_RxCmdAdd_H[0]); //Write command Addr=0xBF(W=1+0x3F ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&REG0_TxCmdAdd_H[1],1,(uint8_t*)&REG0_RxCmdAdd_H[1]); //Write REG0 HByte Addr=0x92

ucSPI00_ReadWriteData(1,(uint8_t*)&REG0_TxDataAdd[0],1,(uint8_t*)&REG0_RxDataAdd[0]); //Write Data Addr=0xC0(W=1+0x40 ,write value @ 0x40) 
ucSPI00_ReadWriteData(1,(uint8_t*)&REG0_TxValue[0],1,(uint8_t*)&REG0_RxValue[0]); //Write value=0x01(REG0_EN bit =1) at 0xC0
}

void BQ76942_Device_Reset(void)
{ //------Device Reset commmand 0x0012

ucSPI00_ReadWriteData(1,(uint8_t*)&Device_Reset_TxArr_L[0],1,(uint8_t*)&Device_Reset_RxArr_L[0]); //Write command Addr=0xBE(W=1+0x3E ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&Device_Reset_TxArr_L[1],1,(uint8_t*)&Device_Reset_RxArr_L[1]); //Write command Addr=0x12


ucSPI00_ReadWriteData(1,(uint8_t*)&Device_Reset_TxArr_H[0],1,(uint8_t*)&Device_Reset_RxArr_H[0]); //Write command Addr=0xBF(W=1+0x3F ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&Device_Reset_TxArr_H[1],1,(uint8_t*)&Device_Reset_RxArr_H[1]); //Write command Addr=0x00
}

void SWAP_TO_SPI_Communication_Init(void)
{ //----SWAP TO SPI COMMAND=0x7C35

ucSPI00_ReadWriteData(1,(uint8_t*)&SWAP_SPI_TxArr_L[0],1,(uint8_t*)&SWAP_SPI_RxArr_L[0]); //Write command Addr=0xBE(W=1+0x3E ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&SWAP_SPI_TxArr_L[1],1,(uint8_t*)&SWAP_SPI_RxArr_L[1]); //Write command Addr=0x35



ucSPI00_ReadWriteData(1,(uint8_t*)&SWAP_SPI_TxArr_H[0],1,(uint8_t*)&SWAP_SPI_RxArr_H[0]); //Write command Addr=0xBF(W=1+0x3F ,write process) 
ucSPI00_ReadWriteData(1,(uint8_t*)&SWAP_SPI_TxArr_H[1],1,(uint8_t*)&SWAP_SPI_RxArr_H[1]); //Write command Addr=0x7C
}

void ucSPI00_Read_Cell_1_Lbyte_Voltage(void)
{
ucSPI00_ReadWriteData(1,(uint8_t*)&cell1_Volt_Lbyte_Txarr[0],1,(uint8_t*)&cell1_Volt_Lbyte_Rxarr[0]);//Write command Addr=0x14 //cell volt 1 Lbyte
ucSPI00_ReadWriteData(1,(uint8_t*)&cell1_Volt_Lbyte_Txarr[1],1,(uint8_t*)&cell1_Volt_Lbyte_Rxarr[1]);//Write command Addr=0xFF//dummy byte
}

void ucSPI00_Read_Cell_1_Hbyte_Voltage(void)
{
//---Cell 1 Hbyte-----
cell1_Volt_Hbyte_Txarr[0]=0x15;//0x15 location Read
cell1_Volt_Hbyte_Txarr[1]=0xFF;

ucSPI00_ReadWriteData(1,(uint8_t*)&cell1_Volt_Hbyte_Txarr[0],1,(uint8_t*)&cell1_Volt_Hbyte_Rxarr[0]);//Write command Addr=0x15//cell volt 1 Hbyte 
ucSPI00_ReadWriteData(1,(uint8_t*)&cell1_Volt_Hbyte_Txarr[1],1,(uint8_t*)&cell1_Volt_Hbyte_Rxarr[1]);//Write command Addr=0xFF//dummy byte
}



/**********************************************************************************
Name : ucSPI00_ReadWriteData
Parameters : pTxBuf : Starting Address of Tx Buffer
: ucTxByte: No of Byte to be Tx
: pRxBuff : Rx Buffer Address
Returns : None
Description : To Send & Receive Data on SPI Bus-CH0
***********************************************************************************/

uint8_t ucSPI00_ReadWriteData(uint8_t ucDevID,uint8_t *pTxBuf, uint8_t ucTxByte, uint8_t *pRxBuf)
{
if (ucTxByte < 1U)
{
return 0;
}
else
{ 
ucSPI_CommDevID = ucDevID;
ucSPI_TxByteCount = ucTxByte;
pSPI_TxAdd = pTxBuf;

if(ucSPI_CommDevID==defSPI0_DevID_BMS)
{
pSPI01_RxAdd = pRxBuf;
pSPI00_RxAdd = ucSPI_DummyByte;
}
else
{
if(ucSPI_CommDevID==defSPI0_DevID_Flash)
{
pSPI00_RxAdd = pRxBuf;
pSPI01_RxAdd = ucSPI_DummyByte;
} 
} 

CSIMK00 = 1U; // Disable Interrupt
SDR00L = *pSPI_TxAdd; // Send First Byte
pSPI_TxAdd++; 
ucSPI_TxByteCount--; 
CSIMK00 = 0U; // Enable INTCSI00 interrupt
}

return 1; 
}

/**********************************************************************************
Name : vSPI_ISR_SPI00
Parameters : None
Returns : None
Description : ISR to Transmit & Data on SPI Bus-CH0
***********************************************************************************/
__interrupt static void vSPI_ISR_SPI00(void)
{
*pSPI00_RxAdd = SDR00L; 
pSPI00_RxAdd++;

if (ucSPI_TxByteCount != 0U)
{
SDR00L = *pSPI_TxAdd;
pSPI_TxAdd++; 
ucSPI_TxByteCount--; 
}
else 
{
if (ucSPI_TxByteCount == 0U)
{ 
bSPI_TxStatusFlag = HIGH; 
}
}
}

Hi TI Forum Team,

I am working on BQ76942 EVM board. Actually I want to SPI communication of BQ76942 Device with our Renesas RL78/F13(R5F10BGE) LQFP-48pin microcontroller over SPI00 Chanel.

Hardware connection Details given below how BQ76942 BMS is connected with RL78/F13(R5F10BGE) Microcontroller for SPI00 connection.

BQ76942 Pins ---------------->> RL78/F13(R5F10BGE) Pins

(1 ) SPI_SCLK(26-pin)---->>P1.7(SCK00)

(2) SPI_MISO(27-pin)----->>P1.6(SI00)

(3) SPI_MOSI(28-pin)----->>P1.5(SO00)

(4) SPI_CS(29-pin)------->> P3.0(SSI00)

My Problem points:-

(1) When I sent these following command sequence to Read the Cell 1 Voltage which is at location 0x14 and 0x15 of BQ76941 RAM location. I did not get the value of Cell 1 voltage reading,

some time we get 0x00 and 0xFF from both location.

(2) please look my command sequence or is it right command that I have sent for Cell 1 voltage reading?

(3) If the above command and its sequence is not right way please let me know both right command and its sequence for voltage reading of Cell 1

Note:- (1.) I have Keep the SPI Communication Frequency at 2MHz from controller side , as stated in SPI supporting speed in BQ76942 data sheet.

(2.) I have keep the same BQ76942 SPI Interface logic operates with Clock polarity(CPOL=0) and clock Phase(CPHA=0) as mentioned clock and data timing diagram in BQ76942 data sheet as well as in Microcontroller (R5F10BGE) is which is covered in type4 which highlight in Screen shot attached with it.

BQ76942 SPI Timing Diagram

Microcontroller RL78/R5F10BGE SPI mode Timing diagram

(3) As per above both Timing Diagram Microcontroller Timing Diagram Type4 is equivalent to BQ76942 CPOL=0 and CPHA=0 . so we have keep mode =Type4 in our Microcontroller side.

(4) These above setting I have maintained in our source code in SPI communication from Microcontroller side.

Our command & its sequence what we implement in our source code For Cell 1 Voltage Reading :-

(1)------Device Reset commmand=0x0012
Device_Reset_TxArr_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
Device_Reset_TxArr_L[1]=0x12;//--Lower byte =0x12

Device_Reset_TxArr_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
Device_Reset_TxArr_H[1]=0x00;//--Higher Byte=0x00
//-----------------------------------------------------------------------------
(2)--SWAP TO SPI Command =0x7C35-------
SWAP_SPI_TxArr_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
SWAP_SPI_TxArr_L[1]=0x35;//Lower Byte=0x35

SWAP_SPI_TxArr_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
SWAP_SPI_TxArr_H[1]=0x7C;//Higher Byte=0x7C
//-----------------------------------------------------------------------------
(3)---REG0 Config Enable : Address=0x921B, Data =0x01(REG0_EN bit =1)
//---Addres write(0x921B)
REG0_TxCmdAdd_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
REG0_TxCmdAdd_L[1]=0x1B;//Lower byte=0x1B

REG0_TxCmdAdd_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
REG0_TxCmdAdd_H[1]=0x92;//Higher byte=0x92

//--Data addr write at 0x40=0x01
REG0_TxDataAdd[0]=0xC0;//--(R/W bit=1 for Write)+0x40=0xC0(To write value @ 0x40)
//--Value write
REG0_TxValue[0]=0x01;//Data =0x01(REG0_EN bit =1)
//-----------------------------------------------------------------------------
(4)--REG1=3.3V Enable : Address=0x921A, Data=0x0D(3.3 volt )[REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1]
//---Addres write(0x921A)
REG1_TxCmdAdd_L[0]=0xBE;//--(R/W bit=1 for Write)+0x3E=0xBE
REG1_TxCmdAdd_L[1]=0x1A;//Lower byte=0x1A

REG1_TxCmdAdd_H[0]=0xBF;//--(R/W bit=1 for Write)+0x3F=0xBF
REG1_TxCmdAdd_H[1]=0x92;//Higher byte=0x92

//--Data addr write at 0x40=0x0D
REG1_TxDataAdd[0]=0xC0;//--(R/W bit=1 for Write)+0x40=0xC0(writing value @ 0x40)
//--Value write
REG1_TxValue[0]=0x0D;//--Data =0x0D(REG1V_2=1,REG1V_1=1,REG1V_0=0, REG0_EN bit =1)

//-----------------------------------------------------------------------------
(5)--- cell 1 Lbyte Reading ----
cell1_Volt_Lbyte_Txarr[0]=0x14;//0x14 location Read
cell1_Volt_Lbyte_Txarr[1]=0xFF;

(6)---Cell 1 Hbyte Reading -----
cell1_Volt_Hbyte_Txarr[0]=0x15;//0x15 location Read
cell1_Volt_Hbyte_Txarr[1]=0xFF;
//------------------------------------------------------------------------------

Please let me know where I am wrong so that SPI Communication b/w BQ76942 and R5F10BGE controller not happening.

Your co-operation will be Appreciable.

Thanks & Regards

Pankaj Kumar

over 3 years ago

0 Matt Sunna over 3 years ago

TI__Guru* 77283 points

Hi Pankaj,

From a quick look at your code, it looks like you may have missed a couple of things from the BQ76942 SPI documentation. If you have a logic analyzer, it would be a good exercise to capture the SPI traffic between BQStudio and an EVM first to see some examples of the SPI protocol.

I recommend looking at the examples in Section 5 of the BQ76942 Software Development Guide: (https://www.ti.com/lit/an/sluaa11a/sluaa11a.pdf) This follows the style used by BQStudio. It uses multiple writes of each byte to verify that the command has been received successfully. This is because some transactions are ignored by the device if the internal oscillator is not running (if the device is in SLEEP mode) or if the processor is busy. Once the data on the MISO pin (which should reflect the data previously written on MOSI) shows the correct data, then it is confirmed the packets have been written successfully.

The BQ76952 Technical Reference Manual (https://www.ti.com/lit/ug/sluuby2/sluuby2.pdf) also includes some very important information on the SPI interface. (The final version of the BQ76942 Technical Reference Manual is not yet published since the device has not yet fully released to production, so I recommend using the BQ76952 document for now.) It discusses the use of retries in certain situations and gives approximate times for different commands to complete.

When reading multi-byte data like the Cell1 voltage from 0x14 and 0x15, when the first byte is read, the 2nd byte is latched so that it will be the same voltage reading for both bytes. Therefore, if you repeat the command to 0x14 until you see the command echoed back on MISO, you should read the 0x14 data on the first write to 0x15 (this will be the value that should be paired with the latched reading from 0x15).

Of course it may not be necessary to take this very cautious approach of retries on every command, but it can help until you get a feel for the timing. For example, after reading from 0x14, you need to wait ~50us before the next SPI read for the command to finish executing.

Best regards,

Matt

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BQ76942EVM: SPI Interface problem with RL78/F13(R5F10BGE) Microcontroller