serial port in loopback mode (termios)

[vinayby]

HI all,
a simple problem but has been troubling me since long..

trying to test serial port in Loopback mode.. normally simple transmit works

here is the https://www.captain.at/howto-simple-serial-port-test-example.php

and myversion of the code..

help would be appreciated.. ( i wonder if loopback is supported atall in linux!)


------code--

#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <asm-ppc/delay.h>
#include<asm-ppc/termios.h>




uint8 WriteString[255];
uint8 ReadString[30];
unsigned char EndChar[] = {0x0d};

main()
{

int dev_tty2;
uint8 BytesWritten = 0;
uint8 ReadChars = 0;
uint8 BytesRead = 0;
uint8 Index;
uint8 Loop;

dev_tty2 = open("/dev/ttl1", O_RDWR);
if(dev_tty2 < 0)
{
printf("Cannot open the COM2 Port\n");

return -1;
}

Loop = 0;

do
{
printf("Loop %d\n", Loop);

for(Index = 0; Index < 4; Index++)
ReadString[Index] = '1' + Loop;

ReadString[Index] = 0x0D;
ReadString[Index + 1] = 0x00;
Loop++;
ReadChars = Index + 1;

for(Index = 0; Index < 4; Index++)
printf("%c", ReadString[Index]);

BytesWritten = write(dev_tty2, ReadString, ReadChars);
printf("\n Chars written to port = %d\n", ReadChars);

sleep(2);

BytesRead = pread(dev_tty2, WriteString, 255, 5);


printf("\n No of chars read from port= %d\n", BytesRead);
for(Index = 0; Index < 254; Index++)
{
printf("%c", WriteString[Index]);
}


/* tcflush(dev_tty2, TCOFLUSH);*/
/* tcflush(dev_tty2, TCIFLUSH);*/
sleep(2);

/*getchar();*/
}while ( Loop < 2);



return 0;
}


------------



---output---
# ./uartl
Loop 0
1111
Chars written to port = 5

No of chars read from port= 5
1111
Loop 1
2222
Chars written to port = 5

No of chars read from port= 5
1111 ----> 2222 is expected here..
#
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