Hi All,
I am using nrf52840 in my project and working on sdk 17.0.2. I have an SPI based IC MAX3421E connected to my device. I am able to read and write single bytes through SPI code. But I am having issues with reading and writing multiple bytes. I am not getting proper response when I try to read or write multiple bytes. The sample code from the library and the converted ones are attached below:-
Sample code from MAX3421 library:-
//SAMPLE CODE FROM MAX3421 LIBRARY
BYTE SPI_wr( BYTE data )
{
SSPBUF = data; // write byte to SSP2BUF register
while( !SSPSTATbits.BF ); // wait until bus cycle completes
return ( SSPBUF ); //
}
/* Single host register write */
void MAXreg_wr(BYTE reg, BYTE val)
{
Select_MAX3421E;
SPI_wr ( reg + 2 ); //set WR bit and send register number
SPI_wr ( val );
Deselect_MAX3421E;
}
/* multiple-byte write */
/* returns a pointer to a memory position after last written */
char* MAXbytes_wr( BYTE reg, BYTE nbytes, char* data )
{
Select_MAX3421E; //assert SS
SPI_wr ( reg + 2 ); //set W/R bit and select register
while( nbytes ) {
SPI_wr( *data ); // send the next data byte
data++; // advance the pointer
nbytes--;
}
Deselect_MAX3421E; //deassert SS
return( data );
}
/* Single host register read */
BYTE MAXreg_rd( BYTE reg )
{
BYTE tmp;
Select_MAX3421E;
SPI_wr ( reg ); //send register number
tmp = SPI_wr ( 0x00 ); //send empty byte, read register contents
Deselect_MAX3421E;
return (tmp);
}
/* multiple-bytes register read */
/* returns a pointer to a memory position after last read */
char* MAXbytes_rd ( BYTE reg, BYTE nbytes, char* data )
{
Select_MAX3421E; //assert SS
SPI_wr ( reg ); //send register number
while( nbytes ) {
*data = SPI_wr ( 0x00 ); //send empty byte, read register contents
data++;
nbytes--;
}
Deselect_MAX3421E; //deassert SS
return( data );
}
The above code has been converted to NRF library format.
void max3421eRegWr(uint8_t reg, uint8_t data)
{
SPIWriteLength = 2;
SPIReadLength = 0;
spi_tx_buf[0] = reg + 0x02 ;
spi_tx_buf[1] = data;
spi_xfer_done = false;
nrf_gpio_pin_clear(SPI_SS_PIN);
nrf_drv_spi_transfer(&m_spi, spi_tx_buf, SPIWriteLength, spi_rx_buf, SPIReadLength);
while(spi_xfer_done == false){}; // this flag will be set to true in the spi interrupt handler function
nrf_gpio_pin_set(SPI_SS_PIN);
vTaskDelay(1000);
}
uint8_t max3421eRegRd(uint8_t reg)
{
spi_tx_buf[0] = reg;
spi_tx_buf[1] = 0x00;
spi_xfer_done = false;
nrf_gpio_pin_clear(SPI_SS_PIN);
nrf_drv_spi_transfer(&m_spi, spi_tx_buf, 2, spi_rx_buf, 2);
while(spi_xfer_done == false){};
nrf_gpio_pin_set(SPI_SS_PIN);
return spi_rx_buf[1];
}
char* MAXbytes_rd ( uint8_t reg, uint8_t nbytes, char* data )
{
spi_tx_buf[0] = reg;
nrf_gpio_pin_clear(SPI_SS_PIN);
nrf_drv_spi_transfer(&m_spi, spi_tx_buf, 1, spi_rx_buf, 0);
spi_tx_buf[0] = 0x00;
while( nbytes ) {
*data = nrf_drv_spi_transfer(&m_spi, spi_tx_buf, 1, spi_rx_buf, 0);
data++;
nbytes--;
}
nrf_gpio_pin_set(SPI_SS_PIN);
return( data );
}
uint8_t dataOut[80];
void max3421e_writebytes(uint8_t reg, uint8_t nbytes, char* data)
{
nrf_gpio_pin_clear(SPI_SS_PIN);
dataOut[0] = reg+0x02;
nrf_drv_spi_transfer(&m_spi, dataOut, SPIWriteLength+1, spi_rx_buf, SPIReadLength);
while( nbytes ) {
//SPI_wr( *data ); // send the next data byte
nrf_drv_spi_transfer(&m_spi, data, 1, spi_rx_buf, 0);
data++; // advance the pointer
nbytes--;
}
nrf_gpio_pin_set(SPI_SS_PIN);
}
I feel something is wrong with my "max3421e_writebytes" and "MAXbytes_rd" function. Need some help on this.
Thanks & Regards,
Snehal
