Help 89c5131a with mmc card interface (SPI)!

the curious is that this functions are different depending if you are looking the pdf or the tutorial in this page , is it some kind of error in the web page?

Ha, yeah you are right! The webpage and the PDF file are different...

I recommend you stick with the PDF file...

pdf file is available to download check the link at the bottom of MMC tutorial index page. If you face any kind of problem do post here..

Another question , sorry for having so many questions , but i'm starting to programme this way , and i have a lot of questions . Well , the question is that in page 9 of the pdf ( sending a command to the SD Card ) , appears this line :


/* send CRC */
SPI_Byte((ThisCommand == CMD_GO_IDLE_STATE)? 0x95:0xFF);

Is the question mark correct ? THanks!

and another question.... the delay function that you use how exactly can you know the time of milisecons that it takes? Isn't that possible to know in C ? Thanks!

answering one by one

a = (x >
 y) ? x : y

//the above is a standard style of writing

if(x>
y){
    a = x;
} else {
    a = y;
}

format is (condition) ? result if true : result if false

Now second question:
there is exactly no way to calculate delay using C. problem is different optimization produces different codes which produce different delays.. so there is just rough way to check put break points during call and just after the call to delay function. get the difference in time. of course you have to use a simulator

Thanks for answering ! now i understand a bit more . But i have another question about the turorial , my question is about the time function of the MMD card .... how can i write a time function if i dont have a real time clock? Is there any possibility to just fake the date ? The problem is that i dont really understand the function so i can't fake it . Thanks!!

another question is , when i compile with keil the following errors appears (they are not the only , but i don't know how to solve this , becaause it affects a library that we don't touch in the tutorial the tff . The error is the following :

compiling tff.c...
TFF.C(176): warning C206: 'LD_WORD': missing function-prototype
TFF.C(176): error C267: 'LD_WORD': requires ANSI-style prototype

Thank you very much for your help!!

for time function you can just return a fix time as you don't have RTC.
I will tell Dave to provide whole project in a zip will be helpful.

Hi ! Thank you for your response ! . Yeah it would be great to have the executable , but do you know another solution while Dave doesn't puts the download (becuase i'm a bit in a hurry these days , because it's a project that i have to present in a few days ....) . Only if possible , but thank you anyway!