AVR102 [Modifikasi] ATmega8515

Jika dalam AVR 102 kita diminta untuk memodifikasi :
a. Data di Program Memory dicopy ke BLOCK1.
b. Data di BLOCK1 dicopy lagi ke BLOCK2 dengan urutan terbalik (gunakan stack).
Salah satu idenya adalah menggunakan fungsi pop, sehingga urutannya terbalik.

;**** A P P L I C A T I O N   N O T E   A V R 1 0 2 ************************
;*
;* Title:  Block Copy Routines
;* Version:  1.1
;* Last updated: 97.07.04
;* Target:  AT90Sxx1x (Devices with SRAM)
;*
;* Support E-mail: avr@atmel.com
;* 
;* DESCRIPTION
;* This Application Note shows how to copy a block of data from Program
;* memory to SRAM and from one SRAM area to another
;*
;***************************************************************************

.include "8515def.inc"

 rjmp RESET ;reset handle

;***************************************************************************
;*
;* "flash2ram"
;*
;* This subroutine copies a block of data from the Program memory (Flash) 
;* to the internal SRAM. The following parameters must be set up prior to 
;* calling the subroutine:
;* Z-pointer:  Flash block start address x 2 (WORD oriented code segment)
;* Y-pointer: ram block start address
;* romsize: block size
;*
;* Number of words :5 + return
;* Number of cycles :10 x block size + return
;* Low Registers used :1 (r0)
;* High Registers used :1 (flashsize)
;* Pointers used :Y, Z
;*
;***************************************************************************

;***** Subroutine Register variables

.def flashsize=r16  ;size of block to be copied

;***** Code    

flash2ram:
 lpm   ;get constant
 st Y+,r0  ;store in SRAM and increment Y-pointer
 adiw ZL,1  ;increment Z-pointer
 dec flashsize
 brne flash2ram ;if not end of table, loop more
 ret


;***************************************************************************
;*
;* "ram2ram"
;*
;* This subroutine copies one block of data from one SRAM area to another.
;* The following parameters must be set up prior to calling the subroutine:
;*
;* Z-pointer:  start of RAM area to copy from
;* Y-pointer: start of RAM area to copy to
;* ramsize  :   size of block to copy
;*
;* Number of words :4 + return
;* Number of cycles :6 x block size + return
;* Low Registers used :1 (ramtemp)
;* High Registers used :1 (ramsize)
;* Pointers used :Y, Z 
;*
;***************************************************************************

;***** Subroutine Register variables

.def ramtemp =r1  ;temporary storage register
.def ramsize =r16  ;size of block to be copied

;***** Code    

ram2ram:
 ld ramtemp,Z+ ;get data from BLOCK1
 push ramtemp ;store data to BLOCK2
 dec ramsize  ;
 brne ram2ram ;if not done, loop more
 ldi ramsize, 20

popping:
 pop ramtemp ;get data from BLOCK1
 st Y+,ramtemp ;store data to BLOCK2
 dec ramsize  ;
 brne popping ;if not done, loop more
 ret

;****************************************************************************
;*
;* Test Program
;*
;* This program copies 20 bytes of data from the Program memory to the SRAM
;* area beginning at location BLOCK1. It then makes a second copy to the
;* area beginning at location BLOCK2.
;*
;****************************************************************************

.equ BLOCK1 =$60  ;start address of SRAM array #1
.equ BLOCK2 =$80  ;start address of SRAM array #2

;***** Main Program Register variables

.def temp =r16  ;temporary storage variable

;***** Code

RESET:
 ldi temp,low(RAMEND)
 out SPL,temp ;init Stack Pointer  
 ldi temp,high(RAMEND)
 out SPH,temp

;***** Copy 20 bytes ROM -> RAM

 ldi ZH,high(F_TABLE*2)
 ldi ZL,low(F_TABLE*2);init Z-pointer
 ldi YH,high(BLOCK1)
 ldi YL,low(BLOCK1) ;init Y-pointer
 ldi flashsize,20
 rcall flash2ram ;copy 20 bytes

;***** Copy 20 bytes RAM -> RAM

 ldi ZH,high(BLOCK1)
 ldi ZL,low(BLOCK1) ;init Z-pointer
 ldi YH,high(BLOCK2) ;(not necessary in this specific case)
 ldi YL,low(BLOCK2) ;init Y-pointer
 ldi ramsize,20 
 rcall ram2ram  ;copy 20 bytes
   
forever:rjmp forever  ;eternal loop 

F_TABLE:
 .db 0,1  ;start of table (20 bytes)
 .db 2,3
 .db 4,5
 .db 6,7
 .db 8,9
 .db 10,11
 .db 12,13
 .db 14,15
 .db 16,17
 .db 18,19

Hasilnya :