I use rockbox since it was ported to the iaudio X5 and I never tryied the FM radio.
Last days I wanted to use it and the quality of reception was very poor.
I tryied to boot on the original firmware and reception was OK.
So I decided to look into the radio code and I found the following things:
1) the frequency selection was shifted by 4kHz for the 32.768KHz radio code (by amiconn) comparing it to the philips datasheet instructions, why?
2) the High Cut-Controller is not enabled (third bit of register 4 if counting from 1). This should remove the high frequency interferencies generated by the PLL.
I tried to remove the 4kHz shift (i.e. use the exact datasheet calculation) and I enabled the HCC.
My first impression is that reception is better on my device, but further tests are required to draw conclusions.
Any suggestions? Why point 1) and 2) were coded in this way?
Thank you very much