This is my first discussion here at engineer zone:
We are using the DAC AD5686 daisy chain mode to end with 32 channels for an application.
I was wondering if between the DOUT of one DAC and the DIN of the other DAC a pulldown resistor is required? We are not using it currently.
We are doing several test and so far we've just connected with two DAC's not being available to connect with the 9-12 channels and so on.
Which are the commands for the SPI interface in order to set the Daisy chain and to start data conversion just to test?
Conrad Holt Mestres
You do not need a pull-down resistor between SDO of the first DAC to the SDIN of the next DAC. A detailed explanation on the Daisy-Chain Operation can be found in the data sheet.
The SPI configuration was OK. We finally managed to fix all the DAC's daisy chain connection. We sent the messages following the next structure:
-24Bytes 0x600000 clear command.
-24Bytes 0x800001 configuring the daisy chain on the first device.
-48Bytes 0x6000008000001 clear command to the second device & again daisy chain for the first device
-48Bytes 0x8000018000001 Daisy chain for second device & daisy chain for first device.
Don't know why If we put not operation instead of repeating the daisy chain command the Dout from the 1st device is 0 all time.
Anyways this way seems works.
Thank you for your reply.