ATMEga64L ATMEL Corporation, ATMEga64L Datasheet - Page 288

• Manufacturer Part Number: ATMEga64L
• Description: 8-bit AVR Microcontroller with 64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL Corporation

288
ATmega64(L)
Rdloop:
Return:
yet
Do_spm:
Wait_spm:
Wait_ee:
subi ZL, low(PAGESIZEB)
sbci ZH, high(PAGESIZEB)
ldi
call Do_spm
; re-enable the RWW section
ldi
call Do_spm
; read back and check, optional
ldi
ldi
subi YL, low(PAGESIZEB)
sbci YH, high(PAGESIZEB)
lpm
ld
cpse r0, r1
jmp
sbiw loophi:looplo, 1
brne Rdloop
; return to RWW section
; verify that RWW section is safe to read
lds
sbrs temp1, RWWSB
ret
; re-enable the RWW section
ldi
call Do_spm
rjmp Return
; check for previous SPM complete
lds
sbrc temp1, SPMEN
rjmp Wait_spm
; input: spmcrval determines SPM action
; disable interrupts if enabled, store status
in
cli
; check that no EEPROM write access is present
sbic EECR, EEWE
rjmp Wait_ee
; SPM timed sequence
sts
spm
; restore SREG (to enable interrupts if originally enabled)
out
ret
spmcrval, (1<<PGWRT) | (1<<SPMEN)
spmcrval, (1<<RWWSRE) | (1<<SPMEN)
looplo, low(PAGESIZEB)
loophi, high(PAGESIZEB) ;not required for PAGESIZEB<=256
r0, Z+
r1, Y+
Error
temp1, SPMCSR
spmcrval, (1<<RWWSRE) | (1<<SPMEN)
temp1, SPMCSR
temp2, SREG
SPMCSR, spmcrval
SREG, temp2
; If RWWSB is set, the RWW section is not ready
;restore pointer
;not required for PAGESIZEB<=256
;init loop variable
;restore pointer
;use subi for PAGESIZEB<=256
2490G–AVR–03/04