STM32f4 SPI data was broken

[Sangkyu Kim]

Posted on July 27, 2017 at 13:23

Hi,

I communicate with ADS1299(24bit, 8CH ADC chip) by SPI.

ADS1299 SPI specification is

CPOL=0 CPHA= 1

Max SCLK = 20MHz

and command flow is

1) send read command(0x12)

2) send dummy(x00) to make SCLK and receive 27 byte data.

unsigned char rdata[27];

unsigned char Dummy_buff[27]={0x00};

 HAL_SPI_TransmitReceive(&hspi1,Dummy_buff,rdata,27,5000);

The error is occurring ♯ 4,7,10,13,16,19,22,25 bytes LSB bit.

For example,

ADS1299 send         0xC0 0x00 0x00  0x45 0x20 0xD0 0x00 0x00 0x00 ......... 0x00(27th byte)

STM32 SPI receive   

0xC0 0x00 0x00  0x44 0x20 0xD0 0x01 0x00 0x00 ......... 0x00(27th byte)

The 4th and 7th byte change or not change randomly.......

I check ADS1299 output data using logic analyzer. MISO data is fine.

Do you have any idea or tip to solve this problem?

I attach my code and sreenshot.

#stm32 #spi

[waclawek.jan · Accepted solution]

Posted on July 27, 2017 at 13:34

See erratum titled Corrupted last bit of data and/or CRC, received in Master mode with delayed SCK feedback

JW

[Sangkyu Kim]

Posted on July 27, 2017 at 14:51

Thank you

Waclawek.Jan

I solve the problem by you answer.