Hi,
I am using DAC8168Ic ,this has been connected over a SPI interface to MPC5644 EVM board, The idea is to get a DAC output by sending the data over SPI, but the output vltage of DAC 8168 seems to be toggling, i have copied the code below can anyone give any suggesstion onit?
#include <math.h>
#include "MPC5644A.h"
extern void SpiDrvrInit();
extern void SpiDrvrWrite32(unsigned char cs,unsigned int databuff);
/* ****************************************************************************
* PLL Code
* ****************************************************************************
*/
typedef struct
{
uint8_t eprediv;
uint8_t emfd;
uint8_t erfd;
}T_FMPLL_INITVALS;
#define FMPLL_200MHZ_INDEX 0
#define FMPLL_130MHZ_INDEX 1
#define FMPLL_256MHZ_INDEX 1
/*
* Table containing initialisation values for FMPLL
*/
T_FMPLL_INITVALS fmpll_init_vals [] =
{
{0x04, 0x32, 0x00}, // Fvco = 400Mhz Fsys = 200Mhz
{0x03, 0x1A, 0x00}, // Fvco = 260Mhz, Fsys = 130Mhz
{0x04, 0x40, 0x00}, // Fvco = 512Mhz, Fsys = 256Mhz
};
/*
* Function to initialise system clock and PLL values
*
* In enhanced mode of operation, Fsys is calculated using the following equation:
* Fsys = fref * (EMFD / ((EPREDIV + 1) * 2 ^(ERFD + 1)))
* In case of 564A EVK, the fref is 40Mhz.
* (range from 256 to 512 Mhz)
*/
void initSysclk (int req_clk_index) {
uint32_t esyncr1_val = 0xF0000000
| (((uint32_t)(fmpll_init_vals[req_clk_index].eprediv)) << 16)
| ((uint32_t)(fmpll_init_vals[req_clk_index].emfd));
uint32_t esyncr2_val = ((uint32_t)(fmpll_init_vals[req_clk_index].erfd));
FMPLL.ESYNCR2.R = esyncr2_val; /*Set */
FMPLL.ESYNCR1.R = esyncr1_val;
while (FMPLL.SYNSR.B.LOCK != 1) {}; /* Wait for FMPLL to LOCK */
}
/* ****************************************************************************
* SPI Code
* ****************************************************************************
*/
static void initDSPI_B(void) {
//configure pads
SIU.PCR[105].R = 0x0600; // Chip select DSPI_B_CS, AF1
SIU.PCR[102].R = 0x0600; // SPI Clock DSPI_B_CSK, primary
SIU.PCR[103].R = 0x0500; // DSPI_B_SIN, primary`
SIU.PCR[104].R = 0x0600; // DSPI_B_SOUT, primary
// DAC GPIOS
SIU.PCR[203].R = 0x0200;
SIU.GPDO[203].B.PDO = 1;
SIU.PCR[204].R = 0x0200;
SIU.GPDO[204].B.PDO = 0;
DSPI_B.CTAR[0].R = 0x7EAB000B;
// configure controller
DSPI_B.MCR.R = 0x90010001; /* Configure DSPI_B as master with DSI Configuration*/
}
void SpiDrvrWrite32(unsigned char cs, // chip select to be asserted
unsigned int databuff) // buffer containinng 16-bit data to be transmitted
{
unsigned short *tbuffptr = (unsigned short *)&databuff;
DSPI_B.MCR.B.HALT = 0x0; /* Exit HALT mode: go from STOPPED to RUNNING state*/
// Setting
DSPI_B.DSICR.R = 0x40080001; // increase framesize to 32 bit and CS0 polarity & take from DSIASDR
DSPI_B.DSICR1.R = 0x00000000;
DSPI_B.ASDR.R = databuff;
DSPI_B.MCR.B.HALT = 0x1; /* Exit HALT mode: go from STOPPED to RUNNING state*/
}
/* ****************************************************************************
* DAC Code - DAC8168
* ****************************************************************************
*/
#define DAC8168_CMD_WRITE_REG 0x00
#define DAC8168_CMD_UPDATE_REG 0x01
#define DAC8168_CMD_WRTSELREG_UPDALL 0x02
#define DAC8168_CMD_WRTSELREG_UPDRESP 0x03
#define DAC8168_CMD_PWRDOWN 0x04
#define DAC8168_CMD_WRITE_TO_CC_REG 0x05
#define DAC8168_CMD_WRITE_TO_LDAC_REG 0x06
#define DAC8168_CMD_SOFTWARE_RESET 0x07
#define DAC8168_CHANNEL_ADDR_A 0x00
#define DAC8168_CHANNEL_ADDR_B 0x01
#define DAC8168_CHANNEL_ADDR_C 0x02
#define DAC8168_CHANNEL_ADDR_D 0x03
#define DAC8168_CHANNEL_ADDR_E 0x04
#define DAC8168_CHANNEL_ADDR_F 0x05
#define DAC8168_CHANNEL_ADDR_G 0x06
#define DAC8168_CHANNEL_ADDR_H 0x07
#define DAC8168_CHANNEL_ADDR_ALL 0x0F
void Dac8168Send(uint8_t cmd,uint8_t channel, uint16_t data)
{
uint32_t spi_data = 0x00000000;
// pull LDAC line up
SIU.GPDO[204].B.PDO = 1;
spi_data = ((uint32_t)(cmd & 0x0F)) << 24;
spi_data |= ((uint32_t)(channel & 0x0F)) << 20;
spi_data |= ((uint32_t)(data & 0x3FFF)) << 6;
SpiDrvrWrite32(0x0, spi_data);
SIU.GPDO[204].B.PDO = 0;
return;
}
int main(void) {
volatile unsigned short i = 0;
int adc_min = 0x0, ad_max = 0x1FFF;
double deg , rad ;
//initialise peripherals & pll
initSysclk(FMPLL_256MHZ_INDEX);
initDSPI_B();
Dac8168Send(DAC8168_CMD_SOFTWARE_RESET, DAC8168_CHANNEL_ADDR_ALL, 0x0000);
while (1){
if (i < 0x3FFF)
i++;
else
i= 0;
Dac8168Send(DAC8168_CMD_WRTSELREG_UPDALL, DAC8168_CHANNEL_ADDR_H, 0x1FFF);
}
}
