TMS570LS1224: ADC - sampling two signals at the same time (parallel)

Simon Metzger said:

is its possible to connect the one signal to AD1IN[0] and one signal to AD2IN[0] to sample the signals at the same time?

Simon Metzger said:

Are there other solutions to this problem?

Yes, you can connect the input signal both ADC1IN[0] and ADC2IN[0]. But What I suggested is to connect the input signal to ADC1IN[16] and ADC2IN[0]. The ADC2[0] and ADC1IN[0} use the same signal pin (pin 58), this means that the input signal is connected to PIN 58.

When using both ADC1 and ADC2 on a shared channel, the sample windows must be identical such that the sample windows completely match each other or non-overlapping with a minimum of 2 ADC cycles buffer between the end of one ADC’s sample window and the start of the other ADC’s sample window.

Please limit the shared analog input upper limit to be lower than (VDDA - 0.3V). 

Hi QJ Wang,

I'm sorry, my question was unclear, since I do not want to connect the signals parallel. Please allow me to reformulate my question.

I have two different signals (I/Q radar signals). To preserve the phase-information between the two signals, I need to sample them at the same time (simultaneously).

Therefore my question: To which pins should I connect the two signals?

Hi Simon,

On the TMS570LS1224 platform, ADC1 supports 24 channels, and ADC2 supports 16 channels which are shared with ADC1[23:8].

You can use any of two channels for your application. 

for example ADC1IN[0] and ADC2IN[0], but ADC1IN[8] should not be used because it is shared with ADC2IN[0].

Assumed, I connect signal_1 to AD1IN[0] and signal_2 to AD2IN[0]:

Then, if I assign both AD1IN[0] and AD2IN[0] to conversion Group1, would the signals be converted sequentially and not simultaneously?

Alternatively, if I assign AD1IN[0] to conversion Group1 and AD2IN[0] to Group2, would there still be a delay, because I need to trigger the conversion for each group separately? 

Is there a solution where the two signals can be converted at the exact same time?

Simon Metzger said:

would the signals be converted sequentially and not simultaneously?

If ADC1 GROUP1 and ADC2 GROUP1 use the same trigger, they will start conversion at the same time. 

Simon Metzger said:

if I assign AD1IN[0] to conversion Group1 and AD2IN[0] to Group2, would there still be a delay, because I need to trigger the conversion for each group separately? 

If the ADC1 GROUP1 and ADC2 GROUP2 use the same trigger, the ADC1IN[0] in ADC1 GROUP1 and AD2IN[0] in ADC2 GROUP2 will start conversion at the same time. Each group can have its own trigger event.