51系列串口通讯例程参考仅供文档格式.docx

1、13. voidserial_init（void）14. 15. /ET1=0;/CLR0ABH;禁止T1中断16. TMOD0x20;/MOV89H,#20Htimer1mode2:8-Bitreload（定时器T1模式2:8位自动初值重装）17. TH10xE8;8DH,#0E8H18. TL18BH,#0E8H1200bps,11.05919. TR11;/SETB8EH启动定时器120. SCON0x50;/1:10-bitUART,enablereceiver /（模式1:10位异步发送/接收,使能接收允许位）21. /SM1串行口模式122. /SM023. /REN允许串行中断接

2、收24. SM2O9DH收到有效的停止位时才将RI置1 25. ES0ACH允许串行中断26. EA0AFH总中断开27. 28. /中断方式处理串口数据29. voidserial（void）interrupt4using30. 31. if（RI）32. 33. RI34. 串口接收,采用临时缓冲35. 36. #if037. if（TI）38. 39. TI40. 串口发送,没有必要使用中断方式41. 42. #endif43. 44. /查询方式接收串口数据45. unsignedchargetchar（void）46. 47. while（!RI）;没有收到串口数据则一直等待48.

3、RI=0;49. returnSBUF;50. 51. /查询方式发送串口数据52. voidputchar（unsignedch）53. 54. SBUF=ch;55. TI）;56. TI=0;57. 58. codeunsignedHEX_TAB=0123456789ABCDEF59. voidputhex（unsigned60. 61. i,j;62. i=ch4;63. j=ch&0x0f;64. putchar（HEX_TABi）;65. putchar（HEX_TABj）;66. test.c采用查询方式进行串口通讯的例子采用这种方式的弊端:1.如果对方没有发送数据，则本机无限等

4、待，而不能做其它事情2.如果对方发送数据而本机正做其它事情，那么有可能丢失数据。因此实际上串口接收常采用中断方式，串口发送则不需要。6. #include7. externvoidserial_init（void）;8. externgetchar（void）;9. externch）;10. extern11. voidmain（void）12. 13. i;14. serial_init（）;串口初始化doi=getchar（）;如果没有收到串口数据则一直等待（查询接收串口数据的弊端）+i;-i;观察断点putchar（i）;/在串口显示接收到的ASCII数据（就是把原来收到的数据再送回串

5、口）putchar（）;0xputhex（i）;在串口以十六进制格式显示接收的ASCII数据27. 28. 29. while（1）;30. 8051串口程序8051串口程序.rar M0.ASM31. ;FILE: M0.ASM 32. ;THIS PROGRAM TRANSMITS THE HEX VALUE AA REPETITIVELY ACCROSS THE SERIAL PORT 33. ;OF A MCS-51 MICROCONTROLLER IN MODE 0 34. ;35. ;DETAILS:36. ;37. ;MODE 0: SERIAL DATA EXITS AND E

6、NTERS THROUGH THE RXD PIN. THE TXD PIN OUTPUTS 38. ;THE SHIFT CLOCK. IN MODE 0, 8 BITS ARE TRANSMITTED/RECEIVED STARTING WITH THE 39. ;LEAST SIGNIFICANT BIT. THE BAUD RATE IS FIXED TO 1/12 THE OSCILLATOR FREQUENCY. 40. ;41. ;42. ORG 00H 43. ;44. JMP MAIN 45. MAIN: MOV SCON,#00H ;SET UP FOR MODE 0 46

7、. CLR TI ;READY TO TRANSMIT 47. LOOP: MOV SBUF,#0AAH ;TRANSMIT AAH 48. JNB TI,$ ;WAIT FOR END OF TRANSMISSION 49. CLR TI ;CLEAR TRANSMIT FLAG 50. JMP LOOP ;DO IT ALL AGAIN 51. END 52. _ M1INT.ASM53. ; M1INT.ASM 54. ;55. ;THIS PROGRAM RECEIVES A VALUE ENTERING INTO THE SERIAL PORT PIN RXD AND PUTS 56

8、. ;THE DATA OUT TO PORT 1 57. ;58. ;59. ;60. ;61. ;THE PROGRAM IS DESIGNED TO BE IN A CONTINUOUS NEVER ENDING LOOP UNTIL A BYTE OF DATA HAS BEEN 62. ;COMPLETELY RECEIVED. THE LOOP IS EXITED BECAUSE OF THE OCCURANCE OF A SERIAL INTERRUPT. AFTER 63. ;THE INTERRUPT HAS BEEN SERVICED, THE PROGRAM GOES B

9、ACK INTO ITS ENDLESS LOOP UNTIL ANOTHER 64. ;INTERRUPT OCCURS 65. ;66. ;67. PCON EQU 87H ;DEFINE PCON REGISTER LOCATION 68. ;69. ORG 00H 70. ;71. JMP MAIN 72. ;73. ORG 023H ;STARTING ADDRESS OF SERIAL INTERRUPT 74. JMP SERIAL_INT 75. ;76. MAIN: MOV SCON, #50H ;SET UP SERIAL PORT FOR MODE 0 WITH RECE

10、IVE ENABLED 77. MOV TMOD, #20H ;SET UP TIMER 1 AS AUTO-RELOAD 8-BIT TIMER 78. MOV TH1, #0DDH ;BAUD RATE EQUALS 2400 BAUD AT 16MhZ 79. MOV PCON, #80H ;SET THE DOUBLE BAUD RATE BIT 80. MOV IE, #81H 81. MOV TCON, #40H ;START TIMER 1 82. CLR RI ;ENSURE THAT THE RECEIVE INTERRUPT FLAG IS CLEAR 83. LOOP: JMP LOOP ;ENDLESS LOOP （UNLESS INTERRUPT OCCURS）