I'm using a sensor that outputs binary data on UART.
I connected it to Edison's Serial1 port and tried to read data, but faced several problems.
1)Until LF(0x0A) is sent, Serial1 doesn't work.
My sensor doesn't send LF(0x0A) at the end of message.
When I try to read data (by "read(int fd,char *readbuf,int size);" function), it stops there until 0x0A happens to be sent.
Is there any way to force read before LF(0x0A) is sent ?
2)Can't read following bytes:
0x03
0x04
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
0x11
0x12
0x13
0x15
0x16
0x17
0x1C
0x7F
I suspect these might work as ASCII control code, but I want to prevent it and read as data.
3)Loop back
How to stop loop back of Serial1?
It is not required for most sensors.
I switched pin mode by this
stty -F /dev/ttyMFD1 115200 echo -n "214" > /sys/class/gpio/export echo -n "130" > /sys/class/gpio/export echo -n "248" > /sys/class/gpio/export echo -n "216" > /sys/class/gpio/export echo -n "131" > /sys/class/gpio/export echo -n "249" > /sys/class/gpio/export echo -n "217" > /sys/class/gpio/export echo low > /sys/class/gpio/gpio214/direction echo low > /sys/class/gpio/gpio248/direction echo in > /sys/class/gpio/gpio216/direction echo mode1 > /sys/kernel/debug/gpio_debug/gpio130/current_pinmux echo in > /sys/class/gpio/gpio130/direction echo high > /sys/class/gpio/gpio249/direction echo in > /sys/class/gpio/gpio217/direction echo mode1 > /sys/kernel/debug/gpio_debug/gpio131/current_pinmux echo out > /sys/class/gpio/gpio131/direction echo high > /sys/class/gpio/gpio214/direction
and tried to read data as followed:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
void PrintHex(char *test,int size){
int i; for(i = 0; i < size; i++){ printf("0x%02X ", test[i] & 0x000000FF); } printf("\n");
}
int main(void) {
printf("Serial1 test program starts\n"); int fd; unsigned int readsize; char data[4] = { 0x41, 0x47, 0x42, 0x0A }; if((fd = open("/dev/ttyMFD1",O_RDWR)) < 0){ printf("Device File Open Error\n"); exit(1); } printf("Device File Opened\n"); write(fd,data,4); printf("Tx via /dev/ttyMFD1\n"); while(1){ char readbuf[1024]={0}; readsize = read(fd,readbuf,1024); printf("Rx via /dev/ttyMFD1\n"); PrintHex(readbuf,1024); } close(fd); return 0;
}It works fine for charactor data (a,b,c...), but not for binary data.