usart.s

ATmega16内部ADC的应用：ATmega16内部集成了8路10位逐次逼近型模数转换器

	.module usart.c
	.area text(rom, con, rel)
	.dbfile F:\radio\第十一篇\test-adc\usart.c
	.dbfunc e putchar _putchar fV
;        coutput -> R16
	.even
_putchar::
	.dbline -1
	.dbline 7
; #include <iom16v.h>
; #include "delay.h"
; #define fosc 8000000 //晶振8MHZ
; #define baud 19200	 //波特率
; /*  		字符输出函数 		 */
; void putchar(unsigned char coutput)
; {	 
L2:
	.dbline 8
L3:
	.dbline 8
;    while (!(UCSRA&(1<<UDRE)));
	sbis 0xb,5
	rjmp L2
	.dbline 9
;    UDR=coutput;    
	out 0xc,R16
	.dbline -2
L1:
	.dbline 0 ; func end
	ret
	.dbsym r coutput 16 c
	.dbend
	.dbfunc e getchar _getchar fc
	.even
_getchar::
	.dbline -1
	.dbline 13
; }
; /*  		字符输入函数 		 */	
; unsigned char getchar(void)
; {
L6:
	.dbline 14
L7:
	.dbline 14
;    while(!(UCSRA& (1<<RXC)));
	sbis 0xb,7
	rjmp L6
	.dbline 15
;    return UDR;
	in R16,0xc
	.dbline -2
L5:
	.dbline 0 ; func end
	ret
	.dbend
	.dbfunc e puts _puts fI
;              s -> R20,R21
	.even
_puts::
	xcall push_gset1
	movw R20,R16
	.dbline -1
	.dbline 19
; }		
; /*			字符串输出函数	   	 */	
; int puts(char *s)
; {
	xjmp L11
L10:
	.dbline 21
	.dbline 22
	movw R30,R20
	ldd R16,z+0
	xcall _putchar
	.dbline 23
	subi R20,255  ; offset = 1
	sbci R21,255
	.dbline 24
L11:
	.dbline 20
;    while (*s)
	movw R30,R20
	ldd R2,z+0
	tst R2
	brne L10
	.dbline 25
;    {
; 	  putchar(*s);
; 	  s++;
;    }	
;    putchar(0x0d);
	ldi R16,13
	xcall _putchar
	.dbline 26
;    putchar(0x0a);//回车换行
	ldi R16,10
	xcall _putchar
	.dbline 27
;    return 1;
	ldi R16,1
	ldi R17,0
	.dbline -2
L9:
	xcall pop_gset1
	.dbline 0 ; func end
	ret
	.dbsym r s 20 pc
	.dbend
	.dbfunc e putstr _putstr fV
;              s -> R20,R21
	.even
_putstr::
	xcall push_gset1
	movw R20,R16
	.dbline -1
	.dbline 31
; }
; /*	 	   不含回车换行的字符串输出函数 	 */	
; void putstr(char *s)
; {
	xjmp L15
L14:
	.dbline 33
	.dbline 34
	movw R30,R20
	ldd R16,z+0
	xcall _putchar
	.dbline 35
	subi R20,255  ; offset = 1
	sbci R21,255
	.dbline 36
L15:
	.dbline 32
;    while (*s)
	movw R30,R20
	ldd R2,z+0
	tst R2
	brne L14
	.dbline -2
L13:
	xcall pop_gset1
	.dbline 0 ; func end
	ret
	.dbsym r s 20 pc
	.dbend
	.dbfunc e uart_init _uart_init fV
	.even
_uart_init::
	.dbline -1
	.dbline 40
;    {
; 	  putchar(*s);
; 	  s++;
;    }	
; }	
; /*			UART初始化				*/	
; void uart_init(void)
; {
	.dbline 41
;  UCSRB=(1<<RXEN)|(1<<TXEN);//允许发送和接收
	ldi R24,24
	out 0xa,R24
	.dbline 42
;  UBRRL=(fosc/16/(baud+1))%256;
	ldi R24,26
	out 0x9,R24
	.dbline 43
;  UBRRH=(fosc/16/(baud+1))/256;
	clr R2
	out 0x20,R2
	.dbline 44
;  UCSRC=(1<<URSEL)|(1<<UCSZ1)|(1<<UCSZ0);//8位数据+1位STOP位
	ldi R24,134
	out 0x20,R24
	.dbline -2
L17:
	.dbline 0 ; func end
	ret
	.dbend