Datasheet

ldi r16, (1<<XMM1)|(1<<XMM0)

sts XMCRB, r16

; write 0xAA to address 0x0001 of external

; memory

ldi r16, 0xaa

sts 0x0001+OFFSET, r16

; re-enable PC7:5 for external memory

ldi r16, (0<<XMM1)|(0<<XMM0)

sts XMCRB, r16

; store 0x55 to address (OFFSET + 1) of

; external memory

ldi r16, 0x55

sts 0x0001+OFFSET, r16

C Code Example

(1)

#define OFFSET 0x2000

void XRAM_example(void)

{

unsigned char *p = (unsigned char *) (OFFSET + 1);

DDRC = 0xFF;

PORTC = 0x00;

XMCRB = (1<<XMM1) | (1<<XMM0);

*p = 0xaa;

XMCRB = 0x00;

*p = 0x55;

}

Note: 1. See About Code Examples.

Care must be exercised using this option as most of the memory is masked away.