I'm using AD7779, in SPI control mode.
Just after initialization onf the device (configuring internal registers), I'm calibrating each active channels (Offset and Gain). So I'm changing ADC_MUX_CONFIG register to 0x14 to connect REF-/REF- ==> Calibration of the Offset, every thing works fine then I change ADC_MUX_CONFIG register to 0x08 to have access to 280mV reference voltage to calibrate the Gain.
And all my configuration resets just after changing ADC_MUX_CONFIG register value.
My configuration is the following :
CH0 : Inactive
CH1 : Active, PGA=4, RX_MUX active (config register = 0x90)
CH2 : Inactive
CH3 : Active, PGA=4, RX_MUX active (config register = 0x90)
CH4 & 5 : Inactive
CH6 : Active, PGA=1, RX_MUX active (config register = 0x10)
CH7 : Inactive
I have already seen something like that. The ADC used to reset while using CH0 with RX_MUX active and DC_MUX_CONFIG = 0x08.
Do you have any clue about what is happening ?
Thank you for your help.