Cannot use both the adc units in s7g2 simultaneously. Please help..

I want to use both adc unit1 & unit2 of s7g2 simultaneously, but whenever i give the input signal(voltage) to the channels placed in the different units the voltage read on those respective channels is between 0.13-0.09v. Strangely when i give input signals to the channels belonging to the same unit it works perfectly fine(gives correct results). It seems like when i give input signal to the channels placed in different units the either of the pin  drives the other  to 0v. I am using SK s7g2 board with the following configuration.

adc hal driver instance- g_adc0

Mode- single scan mode with end interupt enabled (priority 1)

channels used- channel3(P0 08) & channel4(P0 09)

adc unit- unit0

 

adc hal driver instance- g_adc1

Mode- single scan mode with end interupt enabled(priority 1)

channels used- channel19(P5 07) 

adc unit- unit1

 

**yes i am using different instances of the adc driver for different unit

**i initialise both the adc units & and its channels in one function( by respective  open & channelconfig api's) and read the adc channels in the respective callback functions of the units.