ADS1278: Is the SPI of the ADC disabled when all channels are disabled?

Hello TI's community and happy new year :-)

I have another question regarding my previous post "ADS1278: Behavior for 2 ADC in Daisy-Chain and /PWDN in several channels"

Indeed, I placed a AND Gate (and not a OR gate) at the interface between the /DRDY outputs of both the ADC and the MCU. However I still have a problem : it seems that when all the channels of the ADC2 are disabled, the SPI communication is also disabled.

The SPI data are correctly sent from ADC1 to ADC2, but ADC2 does not send the data to the MCU.

When I check the datasheet, the only information I found about it is the following (page 29):

"when all channels are powered down, the ADS1274/78 enters a microwatt (μW) power state where all internal biasing is disabled. In this state, the TEST[1:0] input pins must be driven; all other input pins can float. The ADS1274/78 outputs remain driven."

Does it mean that in microwatt power state the SPI is not enabled (it seems to be the case).

Could you please confirm this statement and tell me if there is a way to use the SPI communication when all the channel of the ADC are disabled?

Thanks a lot for your help and have a nice day.

Best Regards,

Benjamin