topic Re: SD card reading with fopen() in Kinetis Microcontrollers

SD card reading with fopen()

Curro — Fri, 08 Jul 2011 22:24:23 GMT

I'm trying to read a text file, 2k of dimension, form sd card, in ESDHC mode.

This is a part of my code:

void Schermata(char* percorso){

MQX_FILE_PTR fp;

unsigned char LOGO[2049];

fp=fopen(percorso,"r");

fscanf (fp, "%s", LOGO);
...

...

fclose(fp);

but in LOGO I find only the first 256 chars of the file.

Where is the mistake?

Many thanks and best regards,

Corrado

Re: SD card reading with fopen()

RobertSignum — Sat, 09 Jul 2011 01:06:57 GMT

Hi,

I would say it is because of some 'safery' limitation of fscanf.

Imagine what will happen if someone will provide file bigger than 2K - fscanf have no way of knowing the size of buffer and your application will crash flat ...

Also "%s" stops reading on space ..., so if LOGO includes space it will only return first word from it.

I would use fread instead of fscanf ...

Regards,

Robert

Re: SD card reading with fopen()

Curro — Sat, 09 Jul 2011 03:18:57 GMT

Many thanks Robert,

no spaces in my .txt but I think the problem is in fscanf "limitations"...

I'll try with fread instead.

Best regards,

Corrado