I am trying to interface to an SD card via a SPI bus. I am able to communicate with the card to initialize it and read the CSD and CID registers. It looks like I am able to read data. When I send the read data command for address 00000000, I get all 0s back. However, when I try to write data to the card, I get a response token of 0x40, which means "Parameter Error". I have tried this with several different addresses and get the same results. Does anyone have any ideas? How do you know what the address space of an SD card is? I have not been able to find that documentation anywhere.

It looks like my problem was caused by me trying to write to a smaller block than the default 512 bytes. The few SD cards that I have tried, do not allow partial block writes according to bit 23 of their CSD registers. Does anyone know of any SD Cards that will allow smaller block writes?