I'm using a USB 2.0 to TTL UART 6PIN CP2102 Module Serial Converter to connect my Leonardo to my Fedora29 box.
I have RX & TX plugged into pins 0 & 1 plus GND is plugged in. No other pins are plugged in.
I'm using the SoftwareSerialExample sketch plus modifications:
#include <SoftwareSerial.h>
SoftwareSerial mySerial(0, 1); // RX, TX
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600); //57600);
/*
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
*/
Serial.println("Goodnight moon!");
// set the data rate for the SoftwareSerial port
mySerial.begin(9600);
mySerial.println("Hello, world?");
}
void loop() { // run over and over
if (mySerial.available()) {
Serial.write("HELLO!"); //mySerial.read());
}
if (Serial.available()) {
mySerial.write("HELLO again!!!"); //Serial.read());
}
}
On the Linux side I've written a piece of C code that polls on /dev/ttyUSB0:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
#include <sys/poll.h>
#include <linux/serial.h>
#define FALSE 0
#define TRUE 1
void set_speed(int fd) {
struct termios opt;
tcgetattr(fd, &opt);
cfsetispeed(&opt, B9600);
cfsetospeed(&opt, B9600);
tcsetattr(fd, TCSANOW, &opt);
}
void set_parity(int fd) {
struct termios tty;
tcgetattr(fd, &tty);
tty.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /* c_iflag input modes */
tty.c_oflag &= ~OPOST; /* c_oflag output modes */
tty.c_cflag |= (CLOCAL | CREAD); /* c_cflag control modes */
tty.c_cflag &= ~CSIZE;
tty.c_cflag |= CS8; /* 8-bit characters */
tty.c_cflag &= ~PARENB; /* no parity bit */
tty.c_cflag &= ~CSTOPB; /* only need 1 stop bit */
tty.c_cflag &= ~CRTSCTS; /* no hardware flowcontrol */
tcsetattr(fd, TCSANOW, &tty);
}
int OpenSerial(char *dev) {
int fd = open( dev, O_RDWR ); //| O_NOCTTY | O_NDELAY
if (-1 == fd) {
perror("Can't Open Serial Port");
return -1;
}
set_speed(fd);
set_parity(fd);
return fd;
}
int main(void) {
struct pollfd fds[1];
ssize_t length;
char buff[512];
char *dev = "/dev/ttyUSB0";
fds[0].fd = OpenSerial(dev);
fds[0].events = POLLIN ;
while (TRUE) {
int n;
n = poll( fds, 1, 5000);
//got data, and look up which fd has data, but we just have 1
if(n > 0) {
//if( fds[0].revents & POLLIN ) {
length = read(fds[0].fd, buff, sizeof(buff) );
buff[length] = 0;
printf("poll:%s\n",buff);
} else {
printf("No data within 5 seconds.\n");
}
}
}
I'm simply writing to the serial port on the Leonardo side and reading from the port /dev/ttyUSB0 on the Fedora side.
I'm using a USB 2.0 to TTL UART 6PIN CP2102 Module Serial Converter to connect my Leonardo to my Fedora29 box.
I have RX & TX plugged into pins 0 & 1 plus GND is plugged in. No other pins are plugged in.
I'm using the SoftwareSerialExample sketch plus modifications:
#include <SoftwareSerial.h>
SoftwareSerial mySerial(0, 1); // RX, TX
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600); //57600);
/*
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
*/
Serial.println("Goodnight moon!");
// set the data rate for the SoftwareSerial port
mySerial.begin(9600);
mySerial.println("Hello, world?");
}
void loop() { // run over and over
if (mySerial.available()) {
Serial.write("HELLO!"); //mySerial.read());
}
if (Serial.available()) {
mySerial.write("HELLO again!!!"); //Serial.read());
}
}
On the Linux side I've written a piece of C code that polls on /dev/ttyUSB0:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
#include <sys/poll.h>
#include <linux/serial.h>
#define FALSE 0
#define TRUE 1
void set_speed(int fd) {
struct termios opt;
tcgetattr(fd, &opt);
cfsetispeed(&opt, B9600);
cfsetospeed(&opt, B9600);
tcsetattr(fd, TCSANOW, &opt);
}
void set_parity(int fd) {
struct termios tty;
tcgetattr(fd, &tty);
tty.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /* c_iflag input modes */
tty.c_oflag &= ~OPOST; /* c_oflag output modes */
tty.c_cflag |= (CLOCAL | CREAD); /* c_cflag control modes */
tty.c_cflag &= ~CSIZE;
tty.c_cflag |= CS8; /* 8-bit characters */
tty.c_cflag &= ~PARENB; /* no parity bit */
tty.c_cflag &= ~CSTOPB; /* only need 1 stop bit */
tty.c_cflag &= ~CRTSCTS; /* no hardware flowcontrol */
tcsetattr(fd, TCSANOW, &tty);
}
int OpenSerial(char *dev) {
int fd = open( dev, O_RDWR ); //| O_NOCTTY | O_NDELAY
if (-1 == fd) {
perror("Can't Open Serial Port");
return -1;
}
set_speed(fd);
set_parity(fd);
return fd;
}
int main(void) {
struct pollfd fds[1];
ssize_t length;
char buff[512];
char *dev = "/dev/ttyUSB0";
fds[0].fd = OpenSerial(dev);
fds[0].events = POLLIN ;
for(;;) {
int n;
n = poll( fds, 1, 5000);
//got data, and look up which fd has data, but we just have 1
if(n > 0) {
//if( fds[0].revents & POLLIN ) {
length = read(fds[0].fd, buff, sizeof(buff) );
buff[length] = 0;
printf("poll:%s\n",buff);
} else {
printf("No data within 5 seconds.\n");
}
}
}
I'm simply writing to the serial port on the Leonardo side and reading from the port /dev/ttyUSB0 on the Fedora side.
Separation of USB and serial communication. On the Leonardo, Leonardo ETH and Micro, the main Serial class refers to the virtual serial driver on the board for connection to your computer over USB. It's not connected to the physical pins 0 and 1 as it is on the Uno and earlier boards. To use the hardware serial port (pins 0 and 1, RX and TX), use Serial1. (See the Serial reference pages for more information.)
The configuration I was working with had both Leonardo's USB plugged into the Fedora box and the CP2102 USB-to-UART Bridge Controller plugged into the Fedora box. That's why I had both:
ls /dev/serial/by-id/
lrwxrwxrwx. 1 root root 13 Mar 6 18:13 usb-Arduino_LLC_Arduino_Leonardo-if00 -> ../../ttyACM0
lrwxrwxrwx. 1 root root 13 Mar 6 18:13 usb-Silicon_Labs_CP2102_USB_to_UART_Bridge_Controller_0001-if00-port0 -> ../../ttyUSB0
That's NOT the configuration I need. I need the CP2102 USB-to-UART Bridge Controller plugged into the Fedora box and Leonardo's USB port plugged into another box in BIOS setup.
When I plug the Leonardo's USB port into another box, I loose /dev/ttyACM0. When I try open'ing then read'ing from /dev/ttyUSB0 I get nothing.
in loop() is printing to /dev/ACM0, the USB port. The CP2102 USB-to-UART Bridge Controller connected to pins 0 & 1 accomplishes nothing. If I try read'ing from it using /dev/ttyUSB0 I get nothing.
in loop() is printing to /dev/ACM0, the USB port. The CP2102 USB-to-UART Bridge Controller connected to pins 0 & 1 accomplishes nothing. If I try read'ing from it using /dev/ttyUSB0 I get nothing.
