find out adc sampling time

[pavanvulichi]

hello,i am using nrf52 DK.I was testing ADC example code .I am giving acq time is 3microsec .I want to find the total time is taken to sample adc for one sec.In data sheet if acq time is given as 3 micro sec then ADC sample rate is 200 kilo sample per sec.so i want to find out by my own. I don't have oscilloscope. can any one suggested me how to find adc sampling time for 1 second by using Saadc example code.

note:sampling time means the time taken to sample ADC

[Jørgen Holmefjord]

The sample time will be the acquisition time, tACQ, that you configure in your application, pluss the conversion time, tCONV = < 2µs. I don't understand what you are asking for.

[pavanvulichi]

hello sir,in data sheet the sampling rate is 200k samples/sec when tACQ is 3usec & tCONV= < 2µs .But i want to test the exact sampling rate by using example code saadc. can you give any suggestion that how can i find out sampling rate by using example code saadc. In that example there is a timer 400ms for sampling 5 samples. But my goal is to find how many samples can sampled for 1 second.Can any one suggest me how to find no.of samples sampled for 1 second.

[Jørgen Holmefjord]

There is no good way to test this. If the SAADC is put into continuous mode by using PPI/shorts to trigger sampling, you will be able to achieve a sampling rate of 1/(tACK + tConv) (with a single channel enabled). You could try toggling a GPIO on the SAMPLE task and DONE event using PPI and measure the time using an oscilloscope. Take a look at this example.