Control of AD5590 with one of the SPI bus of a Raspberry


We are using the AD5590 both for its capabilities of DAC and ADC.

We are able to control the DAC with the Raspberry SPI0 bus by linking SCLK, MOSI, CE0 and CE1 (Raspberry) to the AD5590 pins, DSCLK, DDIN and DSYNCK1 and DSYNCK2 respectively.

We have programmed an other GPIO to obtain a third CE2 (GPIO26), which seems working fine.

In order to control with the same bus SPI0 the ADC, I make the connection between DDIN and ADIN, and between MISO (of the Raspberry) to ADOUT. And finally I have connected together the clock DSCLK to ASCLK.

After this last connection I am not able to control the DAC. the other previous connections do not interfere with the functioning of the DAC when using the program

ie. I am not able to control the VREF to 0 to 2.5V or inversely, using the same program working well without the connection between the DSCLK and ASCLK.

Could  you explain why, what is the problem (I am beginner on  this kind of bus) ? The level of the clock has been measured on the card and is closed to 3.3V (DSCLK connected or not to ASCLK)

We have already controlled  both the DAC and the ADC on a same program but we have used two different SPI bus(there is an other SPI called SPI1 on the raspberry with already three chip select available, but our goal is to control two cards each having an AD5590 with a single Raspberry).

Thanks for your help.

Yours sincerely.

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