I need to connect SD card to BF532 on my custom board. I know that it is not a good idea to use BF532 for this purpose but I can't change it. The card is connected to the processor according to EE335 PPI Interface 1. I did some changes in a source code (functions.c) and it worked with 1bit bus and 1MHz clock. As a next step I tried to change width of the data bus. Inicialization is ok, block reading works too. Unfortunatelly block writing doesn't work and I cant find why. The card sends negative CRC status (101). I use simple data block 512 x 0xFF, CRC is 0x7FA1. Part of my code is attached (functions SingleBlockWrite() and SetUpTransmitData()). Clock is 250kHz. Slower clock (25kHz) doesn't help. I checked every signal by an oscilloscope. Startbit, stopbit, clock, everything is ok. Can anybody help?