DAC71416: MISO output not readable

Hi,

I just want to ask couple questions.

1. Are you facing issue only in read back?

2. Whats the value of reference voltage on the device after power up?

3. Which register are you trying to read back?

4. SDO mode? ( FSDO settings)

Please note that read back requires two SPI frames, first frame SDI will be read command and second frame can be any command.

during the second frame of the SPI, you will get the requested data on SDO.

Can you please post CS, SCLK, SDI & SDO wave forms? In your post why SDI is having some offset ( waveform is centered around zero?)

Regards,

AK

Hi,

1.yes

2.

3.Device ID of DAC71416

4.SDO is enabled.

i am looking for device id in DAC71416. in KEIL software through SPI configuration.

 here in this dac we using 24bit. in this 24th bit represent the read/write operation.

23rd bit is 0 for write operation

23rd bit is 1 for read operation.

22nd is dont care 

21-16th bit is 

Register address. Specifies the register to be accessed during the read or
write operation.

15-0 bit is 

Data cycle bits. If a write command, the data cycle bits are the values to be
written to the register with address A[5:0]. If a read command, the data
cycle bits are don't care values.

before accessing the device id we must enable the streaming mode , SDO enable, FSDO enable in  SPICONFIG register. 

so i am writing 

0X03000D;

Then i am reading 

0X810000;

This is the main program,that too i puted in while loop 

SPIx_EnableSlave();

/*write operation*/

SPIx_Transfer(0x03);//enable spiconfig

SPIx_Transfer(0x00);

SPIx_Transfer(0x0D);// Streaming,sdo,sdo updates at rising edge

SPIx_DisableSlave();

SPIx_EnableSlave();

/*write operation*/

SPIx_Transfer(0x81);//enable device id

SPIx_Transfer(0x00);
SPIx_Transfer(0x00);


SPIx_DisableSlave();

but i am not getting the device id 

2. External 2.5v

Hi Sasi,

Can you please share the scope shots of your SPI frame?

Regards,

AK