Hi Liu,
To confirm your question, 1. you would like to have simultaneous update of the 8 DAC channels on the DAC61408? And 2. connect multiple DAC61408 devices together with the same CS?
1. Are all DAC channels using the same output? If so, you can use the broadcast register to update all DAC channels with the same data.
If you are using the broadcast register, make sure the BROADCAST-EN bit for each channel is set to 1. This is the device default.
If the output channels require different data, you can update the data for each channel in the respective data register and use the LDAC pin or software LDAC to trigger a synchronous update. The outputs will all update to the values in their data registers when the LDAC is triggered.
If you are using synchronous mode, make sure the SYNC-EN bit for each channel is set to 1. This is not the device default.
2. Are all DAC channels using the same output? If so, you can connect multiple devices together with the same SPI and CS and use the broadcast register to update all of the outputs as I previously described.
You will not be able to use this method if the output channels require different data. You can still use they synchronous mode as I previously described to update the output channels at the same time, but channel 0 on both devices will have the same data, channel 1 on both devices will have the same data, and so on.
You can use daisy chain mode if all channels require different data. The SDI pin of the second DAC is connected to the SDO pin of the first DAC, and the data is clocked in with an extended SPI frame.
Best,
Katlynne Jones
