QN9080 - ADC Timing Test

[shai_b]

Hello Team,

My customer is using QN9080 for his new design, the customer has tested the ADC Timuung by trigger sample in single-mode and measured the time till finished to convert the results and he found out all the conversion process took 200us which is a lot.

Attached you find the sample program which reproduces the conversion results in the attached picture:

- In the picture, the Yellow channel on the scope represents the CTIMER output pin which is set to toggle mode
- In the picture, the Green channel on the scope represents the pin which is flicked on-and-off once ACD conversion is done
- In the picture, see the time gap between two samples to be ~200us, where we would expect a maximum of ~35us

please advise back, thanks in advance 

kind regards,

Shai

[mario_castaneda]

Hi Shai,

I have been checking your CTIMER configuration. Remember the matchValue is the value where the counter is gonna trigger the interruption. 

The bus timer, in this case, is 16MHz because the default configuration is not setting a divider. Also, remember that this value should have a count of the period.

You are looking for a frequency of 28.5Khz, so it should be 16Mhz/28.5Khz=561 and could the period it should be 280.

    ctimer_match_config_t matchConfig;
    matchConfig.enableCounterReset = true;
    matchConfig.enableCounterStop = false;
    matchConfig.matchValue = BUS_CLK_FREQ / 280;//2048;
    matchConfig.outControl = kCTIMER_Output_Toggle;
    matchConfig.outPinInitState = false;
    matchConfig.enableInterrupt = false;‍‍‍‍‍‍‍

Please let me know if you are still facing this issue.

Regards,

Mario