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ADC_ETC sync mode questions on rt1050

Question asked by Jack King on Aug 11, 2018
Latest reply on Aug 12, 2018 by Jack King

I asked a similar question in the MCUXpresso SDK area without a response...

 

I am a bit confused by ADC_ETC sync mode, unsure of what the trigger chain length should be in sync mode (1?)

Chains aren't really explained in the reference manual.

 

When using the SYNC mode of the ADC_ETC trigger to trigger both ADC1 and ADC2 simultaneously, is only a single trigger needed? (trig 0 using software) or are two triggers actually used (0 & 1)?

 

If using a single trigger, how do you configure the channels for both ADC1 and ADC2 in the single trigger config, ADC1 and ADC2 must have different channels, but the trigger only allows specifying one channel.

 

If both ADC1&2 are both triggered by trigger 0, how can you read the results from both, since the result register only holds the value from one ADC for the trigger? Or do you have to read the results from the ADC results buffers directly? Or will the done0 interrupt be called multiple times, once for each ADC, and the results for the corresponding ADC will be in the same result register?

 

I have tried both ways in code and don't see the results from ADC2 at all, and the done 0 interrupt is only called once from the trigger.

 

From this diagram in the Reference Manual, it looks like both ADC are triggered from a single trigger, and the results are stored in the same buffer (RstBuf0?), which I assume would be TRIG0_RESULT_1_0->DATA0 in the case of a single trigger from trigger 0?

 

 

Any clarifications are appreciated!  

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