Chapter 5 ParametersVFD-S Series
3.7 Communication program of PC:
The following is a simple example of how to write a communication program for Modbus ASCII mode on a PC in C language.
#include<stdio.h>
#include<dos.h>
#include<conio.h>
#include<process.h>
#define PORT 0x03F8 /* the address of COM1 */ /* the address offset value relative to COM1 */ #define THR 0x0000
#define RDR 0x0000 #define BRDL 0x0000 #define IER 0x0001 #define BRDH 0x0001 #define LCR 0x0003 #define MCR 0x0004 #define LSR 0x0005 #define MSR 0x0006 unsigned char rdat[60];
/* read 2 data from address 2102H of AC drive with address 1 */ unsigned char tdat[60]={':','0','1','0','3','2','1','0',’2', '0','0','0','2','D','7','\r','\n'}; void main(){int i;
outportb(PORT+MCR,0x08); | /* interrupt enable */ | |
outportb(PORT+IER,0x01); | /* interrupt as data in */ | |
outportb(PORT+LCR,(inportb(PORT+LCR) 0x80)); |
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/* the BRDL/BRDH can be access as LCR.b7==1 */ |
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outportb(PORT+BRDL,12); | /* set baudrate=9600, 12=115200/9600*/ | |
outportb(PORT+BRDH,0x00); |
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outportb(PORT+LCR,0x06); | /* set protocol, <7,N,2>=06H, <7,E,1>=1AH, <7,O,1>=0AH, | |
<8,N,2>=07H, <8,E,1>=1BH, <8,O,1>=0BH | */ | |
for(i=0;i<=16;i++){ |
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while(!(inportb(PORT+LSR) & 0x20)); /* wait until THR empty */ | ||
outportb(PORT+THR,tdat[i]); | /* send data to THR */ | } |
i=0; |
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while(!kbhit()){
if(inportb(PORT+LSR) & 0x01){ /* b0==1, read data ready */ rdat[i++]=inportb(PORT+RDR); /* read data form RDR */
} } }
Revision August 2006, SE08, SW V2.61 |
