esp32c3 > spi > send words fail

[BugSimpson]

Hello,

Why is the last data packet (see picture) always one of the next transmission?

Code: Untitled.c Select all

void spi_write_words( uint16_t * _data, uint8_t _length )

{

  if( _length > 16 ) _length = 16;  



  REG_WRITE( SPI_MS_DLEN_REG,(  ( 16 * _length) -1 ) );

  spi_write_buffer( (uint32_t*)_data, _length );



  REG_SET_BIT( SPI_CMD_REG, SPI_UPDATE_bm );

  while ( REG_READ( SPI_CMD_REG ) & SPI_UPDATE_bm ){};



  REG_SET_BIT( SPI_CMD_REG, SPI_USR_bm );

  while ( REG_READ( SPI_CMD_REG ) & SPI_USR_bm ){};     

}

Code: Untitled.c Select all

void max7219_write( uint16_t* _data, uint8_t _length )

{

  spi_write_words( _data, _length );

}

Code: Untitled.c Select all

    while (1)

    {    

        uint16_t *pData, buffer[ 4 ];

        pData = buffer; 



        for (uint8_t i = 0; i < 4; i++)

        {

          *pData++ = REG_DISPLAY_TEST << 8 | 1;

        } 

        max7219_write( buffer, 4 );   





        pData = buffer; 



        for (uint8_t i = 0; i < 4; i++)

        {

          *pData++ = REG_DISPLAY_TEST << 8 | 0;

        } 

        max7219_write( buffer, 4 );      

    }

sni.JPG (86.12 KiB) Viewed 2011 times

[MicroController]

Why is the last data packet (see picture) always one of the next transmission?

Maybe a bug in some other code?

Code: Select all

  spi_write_buffer( (uint32_t*)_data, _length );

should probably be

Code: Select all

  spi_write_buffer( (uint32_t*)_data, _length/2 );

[BugSimpson]

The number of bytes is correct. Is it possible that there is still a bit that needs to be queried if the transmission is ready?