How to use DMA in NRF52 while writing on SD card, while BLE is also operating?

[Ankush]

Hi,

In my application of interfacing SD card with nrf52, I am using SAADC to sample the input signal at 1000 samples per seconds. These samples I am combining in 84 packets each consisting 12 samples and 20 bytes. In one second I am sending 84 packets over BLE to remote tablet device.

So, I want to write these packets in SD card. Writing one packet at a time is not a good practice. So I want to write 40 packets at a time in SD card. For this I need DMA. As I am never used DMA before, I want to understand what is the correct steps to use DMA for my application.

Does any one has any idea about this?

SDC+BLE.c

[Ankush]

Hi,

As I am doing BLE transmission and writing to SD card in parallel, writing one packet to SD card each time(at 1ms interval) would affect the BLE transmission and my MCU would be busy doing these operations. Instead of this I m looking into the method, which can store each packet to memory, till the level of 40 packets reached.

I am interfacing SD card with nrf52 using FATFS sample example given in SDK12.0. I have added basic interfacing code Here

Using Direct memory Access (DMA) of SAADC or SPI Can I achieve these task?