I'm using an Atmega644p with an SD card (Chans FATFS) and a VS1011e mp3 decoder on the same SPI bus. The problem I'm having is that the SD card stops working when I connect the VS1011e to the SPI bus. More specifically, it stops working when I connect the MISO of the VS1011e to the SPI bus. The chip select for the VS1011e should float this output so it will not interfere so I'm not sure what's going on. Is there anyway to test the pin and see if it's really highZ? Any ideas would be appreciated.