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+--- Thread: Kako simulirati /dev/usbserial na Linux-u (/showthread.php?tid=2315)
Kako simulirati /dev/usbserial na Linux-u - mikikg - 12-26-2019
Pozdrav,
pravim neki desktop program za Linux u C++ koji treba da prica sa nekim USB periferijama (seriski terminali, USB->serial) i trenutno imam potrebu da simuliram to ponasanje periferija jer trenutno nemam te uredjaje, imam samo protokol kako radi i koji cu da isprogramiram u simulatoru.
Interesuje me kako da simuliram /dev/NESTO da bude istog tipa/osobina kao i ovi USB-seriski konverteri?
Trenutno koristim ovako nesto za pisanje na "pravi" device iz glavnog programa:
Code:
// ...
//open port
cout << "Opening MCU on " << dev_mcu << endl;
fd_mcu = open(dev_mcu.c_str(), O_RDWR);
if (fd_mcu < 0) {
std::cerr << "ERROR opening MCU on " << dev_mcu << std::endl;
} else {
struct termios options;
tcgetattr(fd_mcu, &options);
options.c_cflag = B9600 | CS8 | CLOCAL | CREAD; //<Set baud rate
options.c_iflag = IGNPAR;
options.c_oflag = 0;
options.c_lflag = 0;
tcflush(fd_mcu, TCIFLUSH);
tcsetattr(fd_mcu, TCSANOW, &options);
std::cout << "Configured MCU on " << dev_mcu << " as B9600 CS8 IGNPAR" << std::endl;
}
// ...
//write to port
if (write(fd_mcu, cmd_buff_mcu, cmd_buff_mcu_len) != cmd_buff_mcu_len) {
std::cerr << "ERROR writing CMD to MCU device!" << std::endl;
}Kako mogu tu u simulatoru da se "podmetnem" a da ne menjam osnovni code-e za komunikaciju (eventulano promenim samo ime uredjaja) ?
RE: Kako simulirati /dev/usbserial na Linux-u - enaB - 12-26-2019
Mozes da napravis mali C programcic koji ce da pravi par pseudo-terminala https://linux.die.net/man/7/pty
pa jedan kraj (/dev/pts/X) otvori program koji pravis, a drugi, za koji dobijes samo fajl-deskriptor, nema ga u /dev/, sam taj program koji je i napravio terminale. Ponasa se kao pravi port, samo ne simulira stvarnu brzinu prenosa
RE: Kako simulirati /dev/usbserial na Linux-u - mikikg - 01-05-2020
Reseno.
Evo minimalisticki primer za simulator.
Prvo se pokrene socat i tu ispise koja dva terminala je rezervisao (u primeru /dev/ttys019 i /dev/ttys022, menja se):
Code:
socat -d -d pty,raw,echo=0 pty,raw,echo=0
2019/12/26 19:12:07 socat[20685] N PTY is /dev/ttys019
2019/12/26 19:12:07 socat[20685] N PTY is /dev/ttys022
2019/12/26 19:12:07 socat[20685] N starting data transfer loop with FDs [5,5] and [7,7]Dakle jedan (pravi) program gadja /dev/ttys022 dok se simulator podesi na drugi /dev/ttys019 (ili obrnuto, nebitno) i onda dalje ide vec po protokolu ...
Code:
//
// sim_mcu.cpp
// Created on 12/27/19.
// g++ sim_mcu.cpp -o sim_mcu
//
#include <iostream>
#include <unistd.h>
#include <sys/termios.h>
#include <fcntl.h>
using namespace std;
int main() {
char buf [100];
int n = 0, cnt = 0;
int fd_mcu;
string dev_mcu = "/dev/ttys019";
//-------------------------------------
//HW I/O | USB MCU 9600,8,n,1 ---------
//-------------------------------------
//cout << "Opening MCU on " << dev_mcu << endl;
fd_mcu = open(dev_mcu.c_str(), O_RDWR);
if (fd_mcu < 0) {
std::cerr << "ERROR opening MCU on " << dev_mcu << std::endl;
} else {
struct termios options;
tcgetattr(fd_mcu, &options);
options.c_cflag = B9600 | CS8 | CLOCAL | CREAD; //<Set baud rate
options.c_iflag = IGNPAR;
options.c_oflag = 0;
options.c_lflag = 0;
tcflush(fd_mcu, TCIFLUSH);
tcsetattr(fd_mcu, TCSANOW, &options);
std::cout << "Configured MCU on " << dev_mcu << " as B9600 CS8 IGNPAR" << std::endl;
}
while (cnt++ < 100) {
n = read(fd_mcu, buf, sizeof buf); //blocking!
cout << cnt << ": " << "got " << n << " chars in buffer: [ ";
for (int x=0; x<n; x++) {printf("%02X ", buf[x]);}
cout << "]" << endl;
}
return 0;
}