I've connected a microSD card to the SPI0 interface of a BF518. The SPI clock is set to 11MHz, CCLK at 396MHz and SCLK at 66MHz. Since there is a file system on the sd card the read and write operations are done in blocks of 512 bytes. Because the communication is bidirectional I'm using the interrupt version of the device driver library supplied with VDSP (adi_spi_int.c). The signals on the clock and data lines show a gap between consecutive byte transfers of about five microseconds. This slows the data transfer rate down to a disappointing 200kHz.
Is there something wrong with my setup? How can I get faster?
Thanks for the help.