I am connecting 3 AD5292's on one SPI channel. So SCLK, DIN, and SDO are all shared. The !SYNC pins are independently controlled. I know about the pull up resister on the SDO. I will only be talking to one chip at a time. I am worried about my master not being able to receive data from a SDO pin because of the other SDO pins on the channel. I know that the SDO pins need to be high impedance when not used. Will the chip put the SDO in high impedance when !SYNC is high, or do I have to do it?
page 25 says "To place the pin in high impedance and minimize the power dissipation when the pin is used, the 0x8001 data word followed by Command 0 should be sent to the part." Can you elaborate on this?
You need to send command 0x8001 followed by 0x0000.
This will place the SDO pin at high impedance.
The SDO will be enable automatically in the next write sequence.