ardupilot/libraries/AP_HAL_Linux/RCInput_115200.cpp

165 lines
4.1 KiB
C++

/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
this is a driver for R/C input protocols that use a 115200 baud
non-inverted 8-bit protocol. That includes:
- DSM
- SUMD
- ST24
*/
#include <AP_HAL/AP_HAL.h>
#if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_DISCO || \
CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_BLUE
#include "RCInput_115200.h"
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <termios.h>
extern const AP_HAL::HAL& hal;
using namespace Linux;
void RCInput_115200::init()
{
fd = open(device_path, O_RDWR | O_NONBLOCK | O_CLOEXEC);
if (fd != -1) {
struct termios options;
tcgetattr(fd, &options);
cfsetispeed(&options, B115200);
cfsetospeed(&options, B115200);
options.c_cflag &= ~(PARENB|CSTOPB|CSIZE);
options.c_cflag |= CS8;
options.c_lflag &= ~(ICANON|ECHO|ECHOE|ISIG);
options.c_iflag &= ~(IXON|IXOFF|IXANY);
options.c_oflag &= ~OPOST;
if (tcsetattr(fd, TCSANOW, &options) != 0) {
AP_HAL::panic("RCInput_UART: error configuring device: %s",
strerror(errno));
}
tcflush(fd, TCIOFLUSH);
}
}
void RCInput_115200::set_device_path(const char *path)
{
device_path = path;
}
void RCInput_115200::_timer_tick(void)
{
if (fd == -1) {
return;
}
// read up to 256 bytes at a time
uint8_t bytes[256];
int nread;
fd_set fds;
struct timeval tv;
FD_ZERO(&fds);
FD_SET(fd, &fds);
tv.tv_sec = 0;
tv.tv_usec = 0;
// check if any bytes are available
if (select(fd+1, &fds, nullptr, nullptr, &tv) != 1) {
return;
}
// cope with there being a large number of pending bytes at
// the start and discard them
do {
nread = ::read(fd, bytes, sizeof(bytes));
} while (nread == sizeof(bytes));
if (nread <= 0) {
return;
}
bool got_frame = false;
if (decoder == DECODER_SYNC ||
decoder == DECODER_SRXL) {
// try srxl first as it has a 16 bit CRC
if (add_srxl_input(bytes, nread)) {
// lock immediately
decoder = DECODER_SRXL;
got_frame = true;
}
}
if (decoder == DECODER_SYNC ||
decoder == DECODER_SUMD) {
// SUMD also has a 16 bit CRC
if (add_sumd_input(bytes, nread)) {
// lock immediately
decoder = DECODER_SUMD;
got_frame = true;
}
}
if (decoder == DECODER_SYNC ||
decoder == DECODER_DSM) {
// process as DSM
if (add_dsm_input(bytes, nread)) {
dsm_count++;
if (dsm_count == 10) {
// we're confident
decoder = DECODER_DSM;
}
got_frame = true;
}
}
if (decoder == DECODER_SYNC ||
decoder == DECODER_ST24) {
// process as st24
if (add_st24_input(bytes, nread)) {
st24_count++;
if (st24_count == 10) {
// we're confident
decoder = DECODER_ST24;
}
got_frame = true;
}
}
uint32_t now = AP_HAL::millis();
if (got_frame) {
last_input_ms = now;
} else if (now - last_input_ms > 1000 && decoder != DECODER_SYNC) {
// start search again
decoder = DECODER_SYNC;
dsm_count = 0;
st24_count = 0;
}
}
#endif // CONFIG_HAL_BOARD_SUBTYPE