Hal_sd_readblocks not working correctly

Posted on March 03, 2015 at 18:14

woops, no message:

Ok so there was another thread where clive1 already helped me work through a number of issues (as well as other posters on other threads, thanks to all of you!) but I still have one strange issue that is different enough for me to want to post another thread so that you all might get a chance to see it.

Essentially, When I use HAL_SD_writeblocks(xxx) it works just fine (fatfs calls this function, I do not do it directly).  It writes in blocks of 512, and (so far as I know) will write as many blocks as it needs (for my current tests im only doing 1024 bytes).

The problem comes in when I call f_read which in turn calls HAL_SD_readblocks(xxx) which has 2 strange errors:

1) It reads half the bytes I specify eg I say read 512 and it reads 256

2) It will only read a maximum of 1 block (512 bytes)

Does anyone have any idea what could be happening?

I have pullups on the lines, 100 nF dc caps on each VCC.

This is an stm32f4xxx processor using keil and the stm32cube f4 v. 1.4 generated code.