AMC1210: AMC1210 data reading

I am using AMC1210 & AMC1204 for precision data conversion.

All the four channels of AMC1210 is connected to independent AMC1204

My register values are as below

Control register - 0x8000

Clock Divide register - 0x0870 (External clock of 32Mhz)

All four filter module configuration

Control Parameter register - 0x0010

Sinc Filte Parameter register - 0x0FFF

Integrator Parameter register - 0x4800

All other registers are at default values

My programming sequence is as below

1. Clear All Modules

2.  Configure all filter Modules

3.  Configure the Control register

4.  Configure the Clock Divide Register

Reading of ADC channel:

Wait for the ACK pin to go high(ACK is connected to the GPIO of the controller)

Read the Interrupt register

Based on the bit setting, read the data registers of the filter modules.

The problem that I am facing is as below

While enabling the filter modules, if a enable each of them individually (ie, only one channel at a time ), the converted value is matching with the input.  This holds good for all the channels.

When I enable all the channels together(4 channel acquisition), I find some of the channels don't read appropriate values(I read some data, but, not matching to the input voltage levels)

What could be the reason?  Am I missing anything? (My ACK pin is pulsing at 15.625KHz, Also verified the SPI reading which is very much within the ACK timing).

Thanks,

Geetha