Content originally posted in LPCWare by dennislumiad on Tue Jun 09 11:38:39 MST 2015
Hi all,
I am facing problems while using the I2S peripheral of the NXP LPC4357. I am using the CMSIS lib and in principle everything works fine for a 44,1KHz mono wav file with a 16 bit word width. However, when I switch to an 8KHz mono wav file with a 16 bit word width, problems are showing up.
In the specs I found that a 16KHz signal is the lowest the I2S peripheral can go. Therefore, I configured it with a 16KHz config and send every sample of my wav file twice to the output buffer.
My question concerns the sound quality. When I am playing the mentioned 8Khz wav file on a 16KHz I2S configuration, the produced sound has a whistle in itself and is more or less deformed. Has anyone face this problem before? Or does anyone understand where this comes from?
For the 44,1KHz wav file a 12MHz clock is fed to the I2S peripheral.
For the 8KHz wav file a 240KHz clock is fed to the I2S peripheral.
Many thanks in advance for your time and consideration!