DAC60508: DAC60508 MRTET

Hi Andrzej,

I see that you have set the SYNC bits to 1, meaning you are using the software LDAC to update the DACs? Do you issue the trigger command after writing to the DACs (WRITE register 0x05 value 0x0010)?

Your declared value for the TRIGGER (uint8_t TRIGGER[] = { 0x05 , 0x00, 0x0A };) would reset the device if you were to write it.  Are you?

Your SPI setup looks correct, but I also rely on an oscilloscope to verify.  Have you checked your output formating?

You did not share your writing sequence, but I think you should do something like:

1. Readback ID to confirm communication.

2. Write the SYNC, CONFIG, and GAIN registers

3. Write to a DAC channel or the broadcast address

4. Write to the TRIGGER register (0x0010)

Confirm output.

Please let me know if that helps, feel free to post an oscilloscope capture for verification if you would like.

Thanks,

Paul

Hello Paul,
thank you for your fast answer.
I tried to do according to your recommendations. Unfortunately it didn't work. Look at the screen please:

What do you think about it?
I have a question about reading the ID. To read ID I need to send Address Bits first?

Thank you and best regards
Andrew

Hi Andrew,

1. I see that you are using a continuous CS frame for this.  This not supported in stand-alone operation.  You need to bring CS high between each write command. As this device was created to support daisy chain operation, only the last command will be latched.

2. To read a register you issue two commands: the first is the read command (0x81 0x00 0x00), the second command can be any SPI transaction, but the readback data is clocked out on that command.  For example, you could use a NOP command (0x00 0x00 0x00).

Thanks,

Paul

Paul,

Indeed, I have not read about CS.

Unfortunately, I still haven't been able to start the DAC.
Look at these registers, please:

uint8_t ID_READ[] = { 0x81 , 0x00, 0x00 };
uint8_t ID[] =         { 0x01 , 0x00, 0x00 };
uint8_t SYNC[] =     { 0x02 , 0x00, 0x00 };
uint8_t CONFIG[] =  { 0x03 , 0x00, 0x00 };
uint8_t GAIN_[] =     { 0x04 , 0x01, 0xFF };
uint8_t TRIGGER[] = { 0x05 , 0x00, 0x00 };
uint8_t BRDCAST[] = { 0x06 , 0x00, 0x00 };
uint8_t STATUS[] =     { 0x07 , 0x00, 0x00 };

I send it this way:

    SPI_1_CS_ON;
    HAL_SPI_Transmit(&hspi1, SYNC, 3, HAL_MAX_DELAY);
    SPI_1_CS_OFF;
    HAL_Delay(1);
    SPI_1_CS_ON;
    HAL_SPI_Transmit(&hspi1, CONFIG, 3, HAL_MAX_DELAY);
    SPI_1_CS_OFF;
    HAL_Delay(1);
    SPI_1_CS_ON;
    HAL_SPI_Transmit(&hspi1, GAIN_, 3, HAL_MAX_DELAY);
    SPI_1_CS_OFF;
    HAL_Delay(1);
    SPI_1_CS_ON;
    HAL_SPI_Transmit(&hspi1, TRIGGER, 3, HAL_MAX_DELAY);
    SPI_1_CS_OFF;
    HAL_Delay(1);
    SPI_1_CS_ON;
    HAL_SPI_Transmit(&hspi1, BRDCAST, 3, HAL_MAX_DELAY);
    SPI_1_CS_OFF;
    HAL_Delay(1);
    SPI_1_CS_ON;
    HAL_SPI_Transmit(&hspi1, DAC_1, 3, HAL_MAX_DELAY);
    SPI_1_CS_OFF;
    HAL_Delay(1);

But I was able to read something from the DAC:

Name : SPI_RecivedData
    Details:"\201(\226"
    Default:0x20000243 <SPI_RecivedData>
    Decimal:536871491
    Hex:0x20000243
    Binary:100000000000000000001001000011
    Octal:04000001103

Can you read something from this?

Greetings,

Andrew

HI Andrew,

The data you read back is 4 bytes long.  Do you know how that data is justified? The command should only be three bytes.

With your SYNC configuration, the TRIGGER and BROADCAST commands are not necessary.  

If you write:

SYNC = 0x0000

CONFIG = 0x0000

GAIN = 0x01FF

DAC1 = 0x8000

Then the DAC should be 1.25V.  

Is that working?

Also, what are your supply values? Can you confirm that the reference pin is 2.5V.

Thanks,

Paul

Hi Paul,

Is the first success! :-)
After uploading the configuration bits, 1.25V appeared on the DAC output.

The supply voltage is 3.3V (VDD, VIO). REF is 2.5V with ground capacitor.

I was able to get the ID. However, they are 3 bytes:

    Hex:0x81
    Binary:10000001

    Hex:0x28
    Binary:101000

    Hex:0x96
    Binary:10010110

Does this look good?

The problem is when I send some DAC value. E.g:

uint8_t DAC_1[] =     { 0x08 , 0xF, 0xFF };  //Sample value of the variable sent to the DAC1

        SPI_1_CS_ON;
        HAL_SPI_Transmit(&hspi1, DAC_1, 3, HAL_MAX_DELAY);
        SPI_1_CS_OFF;

Then the DAC voltage is 0.16V. Below is the SDI signal view:

Paul, what could be wrong?

I am very grateful for your help ...

Greetings,

Andrew