Spi_Xfer..... and questions

joseph20480 · Joined: 21 Dec 2011 Posts: 42

Hi,

I try to use a sdcard on my pic with fat16 system file. I use this code... but it's not in reality my problem...
http://www.ccsinfo.com/forum/viewtopic.php?t=46966

This code use spi_Xfer with the PIC 18f4520. ->> Compilation OK
My question is why when try to compile with my pic, a pic 18f4550, it's doesn't work

>>> *** Error 12 "C:\PROGRA~1\PICC\drivers\mmcsd.c" Line 577(15,16): Undefined identifier -- spi_xfer

the compilateur seems to say me , the spi_xfer fonction is not available... but the 18f4520 and 18f4550 is the same family ... No ?
If you have an idea, an explication.... it's very sympathic to answer me

temtronic · Posted: Wed Dec 21, 2011 2:39 pm

The error may be in a line or two above the one you think it is....
without seeing the code it's hard to say..

however...

a bigger problem may exist.
The 18F4550, as well as the 18F4520 are 5 volt devices and the sd card is probably 3.3 volt( most if not 100% are). So do you have the correct level translators between the 2 devices ?

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

joseph20480 · Joined: 21 Dec 2011 Posts: 42

Thanks for your rapidly reply...

So, i have try to compile my program with

#include <PIC18F4520.h> instead of <PIC18F4550.h>
>>Result Compilation successful
...

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

What's your CCS compiler version ? It's given at the top of the .LST file.
It's a 4-digit number similar to this:
http://www.ccsinfo.com/devices.php?page=versioninfo

Ttelmah · Joined: 11 Mar 2010 Posts: 19253

I'd guess you have an #USE RS232 line.
Problem is that on the 4550, the SPI pins are also used for RS232. SDO, is shared with the RS232 RX. So a #USE SPI, doesn't get accepted, if the pin is in use for RS232....

Best Wishes