Hi, expert
My customer is using DAC8760 pin to pin replace AD5421, but they found no data from DAC output.
They can write into the register to adjust the output current, but when they read the DAC data, the SDO is always low. (LATCH/SCK/SDIN signals are correct)
Attached their code, could you please help analysis this problem? Thanks
Best Regards.
Chen
DAC-DEMO.c
static unsigned char buf[3] = {0,0,0};
static unsigned char buf2[3] = {0,0,0};
statc Modechange=1;
static SetAoValue=0xD554;//20MA
static ReadFromAoStatus=0;
static ReadFromAoData=0;
static ReadFromAoCtrl=0;
//the function write data to the ADC's register (DAC)
void WriteToADC(unsigned char count,unsigned char *buf)
{
unsigned char ValueToWrite = 0;
unsigned char i = 0;
unsigned char j = 0;
//set latch low
GPIOPinWrite(DAC_LATCH_PORT, DAC_LATCH_PIN, ~DAC_LATCH_PIN);
for ( i=count; i>0; i-- )
{
ValueToWrite = *(buf+i-1);
for (j=0; j<8; j++)
{
GPIOPinWrite(DAC_SCK_PORT, DAC_SCK_PIN,~DAC_SCK_PIN);
if(0x80 == (ValueToWrite & 0x80))
{
GPIOPinWrite(DAC_SDI_PORT, DAC_SDI_PIN,DAC_SDI_PIN); //Send one to SDIN pin of AD5422
}
else
{
GPIOPinWrite(DAC_SDI_PORT, DAC_SDI_PIN,~DAC_SDI_PIN); //Send zero to SDIN pin of AD5422
}
SysDelayUs(1);
GPIOPinWrite(DAC_SCK_PORT, DAC_SCK_PIN,DAC_SCK_PIN);
SysDelayUs(1);
ValueToWrite <<= 1; //Rotate data
}
}
GPIOPinWrite(DAC_SCK_PORT, DAC_SCK_PIN,~DAC_SCK_PIN);
SysDelayUs(1);
GPIOPinWrite(DAC_LATCH_PORT, DAC_LATCH_PIN, DAC_LATCH_PIN);
// SysDelayUs(20);
SysDelayUs(10);
}
//the function read the data register from DAC
void ReadFromADC(unsigned char count,unsigned char *buf)
{
unsigned char i = 0;
unsigned char j = 0;
unsigned char iTemp = 0;
unsigned char RotateData = 0;
GPIOPinWrite(DAC_LATCH_PORT, DAC_LATCH_PIN, ~DAC_LATCH_PIN);
for(j=count; j>0; j--)
{
for(i=0; i<8; i++)
{
GPIOPinWrite(DAC_SCK_PORT, DAC_SCK_PIN,~DAC_SCK_PIN);
RotateData <<= 1; //Rotate data
SysDelayUs(1);
GPIOPinWrite(DAC_SDI_PORT, DAC_SDI_PIN,~DAC_SDI_PIN); //Write a nop condition when read the data.
iTemp = GPIOPinRead(DAC_SDO_PORT,DAC_SDO_PIN); //Read SDO of AD5422
GPIOPinWrite(DAC_SCK_PORT, DAC_SCK_PIN,DAC_SCK_PIN);
if(iTemp == 1)
{
RotateData |= 1;
}
SysDelayUs(1);
}
*(buf+j-1)= RotateData;
}
GPIOPinWrite(DAC_SCK_PORT, DAC_SCK_PIN,~DAC_SCK_PIN);
SysDelayUs(1);
GPIOPinWrite(DAC_LATCH_PORT, DAC_LATCH_PIN, DAC_LATCH_PIN);
// SysDelayUs(20);
SysDelayUs(10);
}
void DacDemo(void)
{
//IO���ų�ʼ����ʹ��GPIOģ��SPI
//set control
//�趨0-24MA���
if(Modechange)
{
Modechange=0;
buf[0]=0x07;//0-24ma
buf[2]=0x55;
buf[1]=0x10;
WriteToADC(3,buf);//�趨״̬
SysDelayUs(100);
}
//ͨ�������趨
buf[2] = 0x01; //Data register
buf[1] = (SetAoValue>>8)&0xff;
buf[0] = SetAoValue&0xff;
WriteToADC(3,buf);//
SysDelayUs(100);
//ͨ��״̬�ز�
buf[2] = 0x02;//READ
buf[1] = 0x00;
buf[0] = 0x00;//STATUS
WriteToADC(3,buf);
ReadFromADC(3,buf2);
ReadFromAoStatus=buf2[1];
ReadFromAoStatus<<=8;
ReadFromAoStatus+=buf2[0];
SysDelayUs(100);
//ͨ�����ݻز�
buf[2] = 0x02;//READ
buf[1] = 0x00;
buf[0] = 0x01;//DATA
WriteToADC(3,buf);
ReadFromADC(3,buf2);
ReadFromAoData=buf2[1];
ReadFromAoData<<=8;
ReadFromAoData+=buf2[0];
SysDelayUs(100);
//ͨ�����ƻز�
buf[2] = 0x02;//READ
buf[1] = 0x00;
buf[0] = 0x02;//control
WriteToADC(3,buf);
ReadFromADC(3,buf2);
ReadFromAoCtrl=buf2[1];
ReadFromAoCtrl<<=8;
ReadFromAoCtrl+=buf2[0];
SysDelayUs(100);
}
