vidu4-2.s

h&#432 &#7899 ng d&#7851 n v&#7873 dsp tham kh&#7843 o các c&#244 ng c&#7909 c&#417 b&#7843 n

;*******************************************************************************
;	Vidu4-2.s la chuong trinh viet bang hop ngu de chay tren mot dsPIC		   *
;	Chuong trinh thuc hien viec sau: Doc ky tu tu cong RS232, sau do gui tra   *
;	ky tu da duoc sua doi (cong 1 vao) ve thong qua cong RS232				   *
;*******************************************************************************

;	Tac gia				: Nguyen Quang Nam									   *

;	Don vi				: PIC Viet Nam										   *

;	Ten tap tin			: Vidu4-2.s											   *

;	Ngay				: 09/08/2006										   *

;	Phien ban			: 0.01												   *

;	Nhung tap tin can thiet khac: p30F4012.gld, p30f4012.inc				   *

;	Cong cu duoc dung:	MPLAB 7.31											   *
;						ASM30 2.14											   *
;						LNK30 2.14											   *
;-------------------------------------------------------------------------------

;	.equ __30F2010, 1
;	.equ __30F2011, 1
;	.equ __30F2012, 1
;	.equ __30F3010, 1
;	.equ __30F3011, 1
;	.equ __30F3012, 1
;	.equ __30F3013, 1
;	.equ __30F3014, 1
;	.equ __30F4011, 1
	.equ __30F4012, 1
;	.equ __30F4013, 1
	.include "p30fxxxx.inc"

;	config	__FOSC, CSW_FSCM_OFF & HS
;	config	__FOSC, CSW_FSCM_OFF & HS2_PLL8
;	config	__FOSC, CSW_FSCM_OFF & HS2_PLL16
;	config	__FOSC, CSW_FSCM_OFF & FRC
	config	__FOSC, CSW_FSCM_OFF & FRC_PLL4
;	config	__FOSC, CSW_FSCM_OFF & FRC_PLL8
;	config	__FOSC, CSW_FSCM_OFF & XT_PLL8
;	config	__FOSC, CSW_FSCM_OFF & XT_PLL16
	config	__FWDT, WDT_OFF
	config	__FBORPOR, MCLR_EN & PBOR_OFF
	config	__FGS, CODE_PROT_OFF

;-------------------------------------------------------------------------------
;Cac hang so cua chuong trinh (gia tri tuc thoi dung trong chuong trinh)

	.equiv	Fcy, 8000000	;Tan so thuc thi lenh
	.equiv	baud, 38400		;Toc do baud cua cong RS232

;-------------------------------------------------------------------------------
;Cac khai bao toan cuc:

	.global __reset			;Khai bao nhan bat dau chuong trinh (bat buoc)

;-------------------------------------------------------------------------------
;Doan ma trong vung nho chuong trinh

	.text				;Bat dau doan ma chuong trinh

__reset:       
		mov	#__SP_init, W15	;Khoi tao con tro ngan xep (stack)
		mov	#__SPLIM_init, W0
		mov	W0, SPLIM	;Khoi tao thanh ghi gioi han con tro ngan xep (stack)
		nop				;Can mot lenh NOP sau khi ghi vao SPLIM
		clr	W0			;Xoa thanh ghi lam viec W0
		mov	W0, W14 	;Xoa cac thanh ghi W1 den W14
		repeat	#12
		mov	W0,[++W14]	;Dia chi cua cac thanh ghi: 0x0002 - 0x001C
		clr	W14

;-------------------------------------------------------------------------------
		rcall	Init_UART1		;Khoi tao cong RS232 thu nhat

main_loop:
		btss	U1STA, #URXDA	;Co ky tu gui den?
		bra	main_loop			;Khong, tiep tuc kiem tra
		mov	U1RXREG, W0			;Co, doc ky tu da nhan vao W0
		inc	W0, W0				;sua doi ky tu da nhan
		mov	W0, U1TXREG			;va ghi ky tu da sua doi ra cong RS232
		bra	main_loop			;Tro ve vong lap chinh
;-------------------------------------------------------------------------------

;Chuong trinh con khoi tao cong RS232 thu nhat (module UART1)
;-------------------------------------------------------------------------------
Init_UART1:
		mov	#0x8000, W0		;bit15=UARTEN  bit10=ALTIO, dung Main IO
		mov	W0, U1MODE
		mov	#0x0400, W0		;bit10=UTXEN
		mov	W0, U1STA
        mov	#(((Fcy/baud)/16)-1), W0	;Khoi tao toc do baud
        mov	W0, U1BRG					;=((Fcy/baud)/16) - 1)
		return
;-------------------------------------------------------------------------------

	.end				;Ket thuc phan ma trong tap tin nay