audio recording on SD card with Nano

Hello

My project is : recording audio (mono 16 bits 44kHz) on a SD card.

RedBoard-Artemis-Nano

IDE = Arduino

Two problems:

1/ using SD.h and SPI.h, I cannot reach a sufficient rate of recording (40kb/s instead of 88, for a theoritical minimum of 25Mb/s for a standard SD card !) The speed is limited by SD Write (32768 bytes buffers).

SPI configuration : what is the maximum SPI clock freq usable with a 32Go SDHC ?; changing this parameter seems having no effect (superseded by SD library ?)

2/ when I add PDM library to get data from the integrated mic, recording on SD stops after some seconds > conflict between SD, SPI and PDM ?

Thanks in advance for your help.

Jean-Pierre

Try creating an ‘issue’ on the github for the Apollo3/Artemis here https://github.com/sparkfun/Arduino_Apollo3/issues