# ADC Clock

**URL:** <https://community.sparkfun.com/t/adc-clock/43669>\
**Category:** Artemis\
**Created:** [March 28, 2022, 3:31pm UTC](https://community.sparkfun.com/t/adc-clock/43669 "2022-03-28T15:31:07Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![pcbGuru](https://avatars.discourse-cdn.com/v4/letter/p/c89c15/32.png) [@pcbGuru](https://community.sparkfun.com/u/pcbGuru)\
**Post date:** [March 28, 2022, 3:31pm UTC](https://community.sparkfun.com/t/adc-clock/43669/1 "2022-03-28T15:31:07Z")

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Hello,

I am making a peak detector, and want to feed its signal into the Appolo 3 MCU ADC. It would be great if I could sync the peak detector reset pin with the ADC, so that whenever the ADC takes a sample it reads the latest peak.

Question is, can I somehow bring the ADC clock out to a GPIO pin? I.e, if the clock signal is high, the GPIO pin is high and when the clock is low, the GPIO pin is low.

Thanks.

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**Author:** ![paulvha](https://avatars.discourse-cdn.com/v4/letter/p/65b543/32.png) [@paulvha](https://community.sparkfun.com/u/paulvha)\
**Post date:** [March 28, 2022, 7:40pm UTC](https://community.sparkfun.com/t/adc-clock/43669/2 "2022-03-28T19:40:46Z")

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1. When performing an analogRead() it is a ONE-shot occurrence to read the ADC. Not sure how precise you want to get it/ need it, but the set a GPIO output HIGH, JUST before the analogRead(), might be enough.

2. if you need to get it 100% aligned, the ADC clock in the Sparkfun Library is the HRFC (so 48Mhz). According to the datasheet, this signal is not available on a GPIO. There are different clock sources that can be made available with CLKOUT, HFRC is not part of that.