# Issues while using ADC with DMA(Photon Audio3 example) on E Series

**URL:** <https://community.particle.io/t/issues-while-using-adc-with-dma-photon-audio3-example-on-e-series/59155>\
**Category:** Firmware\
**Tags:** e-series\
**Created:** [January 22, 2021, 8:43pm UTC](https://community.particle.io/t/issues-while-using-adc-with-dma-photon-audio3-example-on-e-series/59155 "2021-01-22T20:43:04Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![dreamER](https://sea2.discourse-cdn.com/flex026/user_avatar/community.particle.io/dreamer/32/26550_2.png) [@dreamER](https://community.particle.io/u/dreamER)\
**Post date:** [January 23, 2021, 5:30pm UTC](https://community.particle.io/t/issues-while-using-adc-with-dma-photon-audio3-example-on-e-series/59155/2 "2021-01-23T17:30:49Z")

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Hi, here is some awesome approach on how to read analog data as fast as possible without involving DMA maybe can help you somehow

> [@Fast ADC readings](https://community.particle.io/t/fast-adc-readings/52263/9):
>
> Thats normal, because i measured 10 us for one analogRead() and millis() allso takes some time. There are also interrupts from the system… I found now a solution myself. I was using the wrong commands from the STM32\_StdPeriph\_Driver lib because i tried to use some from STM32F1xx-generation. Photon is based on STM32F2xx! My working Code with 1.2 µs reading time! /\* \* returns the counts of a given ADC (ADC1 and AD2, ADC3 wans't working) \* takes approx. 1.2 µs \*/ uint16\_t readADCx(ADC\_TypeDef\*…

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