Hi Everyone,
I am working on a hobby project with nRF51822 which needs me sample upto 4 signals reliably at 500Hz each at 10bit resolution. I have read through few posts in the forum([1],[2],[3]) and found that with softdevice installed ADC sampling rate drops to 1KHz(Or Is it 2KHz? As one forum post was suggesting so)
So for my requirement, I am assuming nRF51822 might not be good enough as sampling rate would drop to 1KHz/4 = 250Hz as I have four channels? I would like to know what my options are to implement this spec at 500Hz/channel?
- Is there way to do 500Hz/channel for 4 inputs with latest softdevice installed? (Connection Interval: 7.5ms, Slave latency: 0ms, 1 packet(<20bytes of data) of data transfer per connection interval)
- If I compromise on the sampling rate to 250Hz/channel(or dropping it to 8bit resolution), would I be able to reliably sample all channels with SD installed?
- If its No to the Question 1, is my only option to go for an external ADC with higher sampling rate and transferring data to nRF51822 via SPI?
- Is it better for me switch to nrf52840(Preference is still towards nRF51822)? I have PDK which I can work with for this project. I haven't searched around in the forum for ADC performance of nRF52840 with s140 SD.
Thanks in advance.