AT90PWM2B-16SU View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT90PWM2B-16SU

8-bit Atmel Microcontroller with 8K Bytes In-System Programmable Flash

Atmel Corporation 

4317K–AVR–03/2013

AT90PWM2/3/2B/3B

;-It is assumed that either the interrupt table is moved to the Boot

; loader section or that the interrupts are disabled.

.equ PAGESIZEB = PAGESIZE*2 ;PAGESIZEB is page size in BYTES, not words

.org SMALLBOOTSTART

Write_page:

; Page Erase

ldi spmcrval, (1<<PGERS) | (1<<SPMEN)

call Do_spm

; re-enable the RWW section

ldi spmcrval, (1<<RWWSRE) | (1<<SPMEN)

call Do_spm

; transfer data from RAM to Flash page buffer

ldi looplo, low(PAGESIZEB) ;init loop variable

ldi loophi, high(PAGESIZEB) ;not required for PAGESIZEB<=256

Wrloop:

ld r0, Y+

ld r1, Y+

ldi spmcrval, (1<<SPMEN)

call Do_spm

adiw ZH:ZL, 2

sbiw loophi:looplo, 2

;use subi for PAGESIZEB<=256

brne Wrloop

; execute Page Write

subi ZL, low(PAGESIZEB)

;restore pointer

sbci ZH, high(PAGESIZEB)

;not required for PAGESIZEB<=256

ldi spmcrval, (1<<PGWRT) | (1<<SPMEN)

call Do_spm

; re-enable the RWW section

ldi spmcrval, (1<<RWWSRE) | (1<<SPMEN)

call Do_spm

; read back and check, optional

ldi looplo, low(PAGESIZEB) ;init loop variable

ldi loophi, high(PAGESIZEB) ;not required for PAGESIZEB<=256

subi YL, low(PAGESIZEB)

;restore pointer

sbci YH, high(PAGESIZEB)

Rdloop:

lpm r0, Z+

ld r1, Y+

cpse r0, r1

jmp Error

sbiw loophi:looplo, 1

;use subi for PAGESIZEB<=256

brne Rdloop

; return to RWW section

; verify that RWW section is safe to read

Return:

in temp1, SPMCSR

sbrs temp1, RWWSB

; If RWWSB is set, the RWW section is not ready yet

ret

; re-enable the RWW section

ldi spmcrval, (1<<RWWSRE) | (1<<SPMEN)

call Do_spm

rjmp Return

277

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