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[avr-gcc-list] external memory on atmega128l
From: |
Jan Beutel |
Subject: |
[avr-gcc-list] external memory on atmega128l |
Date: |
06 Dec 2002 11:47:10 +0100 |
hello,
we are using avr-gcc (GCC) 3.3 20020905 with atmega128l and amic
lp62s2048x-70llt external memory.
we are experiencing problems with the external memory access. these
problems seem to increase when options such as -fno-inline-funcions
-Wall and -O6 are used.
if someone who has been using external meory successfully could give us
some hints we would be very glad.
jb
here's an example without waitstates...
#include <avr/io.h>
#include <avr/iom128.h>
#define BUF_ADDR 0x1100
#define BUF_SIZE 0xFFFF - BUF_ADDR
int main( void )
{
s32 i;
volatile u8 *xbuffer;
//disable interrupts
cli();
sbi (MCUCR, SRE); //enable xsram at the very beginning
// to be able to place .bss and .data there
cbi (XMCRB, XMBK); //bus-keeper
cbi(XMCRA, SRW11);
cbi(MCUCR, SRW10);
sbi(DDRF, 7);
cbi(PORTF, 7);
xbuffer = (u8 *) BUF_ADDR;
while (1){
for (i=0; i<BUF_SIZE; i++){
xbuffer[i]=0xFF;
if (xbuffer[i]!=0xFF){
sbi(PORTF, 7);
cbi(PORTF, 7);
}
xbuffer[i]=0x00;
if (xbuffer[i]!=0x00){
sbi(PORTF, 7);
cbi(PORTF, 7);
}
}
}
return 0;
}
--
Jan Beutel address@hidden
Computer Engineering and Networks Laboratory, ETZ G63
ETH Zurich +41 1 632 70 32 Phone
Gloriastrasse 35 +41 1 632 10 35 Fax
CH 8092 Zurich/Switzerland http://www.tik.ee.ethz.ch/~beutel
avr-gcc-list at http://avr1.org
- [avr-gcc-list] external memory on atmega128l,
Jan Beutel <=