ardupilot/libraries/AP_HAL_Linux/RCInput.cpp

333 lines
8.4 KiB
C++

#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>
#include <AP_HAL/AP_HAL.h>
#include <AP_HAL/utility/dsm.h>
#include <AP_HAL/utility/sumd.h>
#include <AP_HAL/utility/st24.h>
#include <AP_HAL/utility/srxl.h>
#include <AP_RCProtocol/AP_RCProtocol_SBUS.h>
#include "RCInput.h"
#define MIN_NUM_CHANNELS 5
extern const AP_HAL::HAL& hal;
using namespace Linux;
RCInput::RCInput()
{
ppm_state._channel_counter = -1;
}
void RCInput::init()
{
}
bool RCInput::new_input()
{
bool ret = rc_input_count != last_rc_input_count;
if (ret) {
last_rc_input_count.store(rc_input_count);
}
return ret;
}
uint8_t RCInput::num_channels()
{
return _num_channels;
}
void RCInput::set_num_channels(uint8_t num)
{
_num_channels = num;
}
uint16_t RCInput::read(uint8_t ch)
{
if (ch >= _num_channels) {
return 0;
}
return _pwm_values[ch];
}
uint8_t RCInput::read(uint16_t* periods, uint8_t len)
{
uint8_t i;
for (i=0; i<len; i++) {
periods[i] = read(i);
}
return len;
}
/*
process a PPM-sum pulse of the given width
*/
void RCInput::_process_ppmsum_pulse(uint16_t width_usec)
{
if (width_usec >= 2700) {
// a long pulse indicates the end of a frame. Reset the
// channel counter so next pulse is channel 0
if (ppm_state._channel_counter >= MIN_NUM_CHANNELS) {
for (uint8_t i=0; i<ppm_state._channel_counter; i++) {
_pwm_values[i] = ppm_state._pulse_capt[i];
}
_num_channels = ppm_state._channel_counter;
rc_input_count++;
}
ppm_state._channel_counter = 0;
return;
}
if (ppm_state._channel_counter == -1) {
// we are not synchronised
return;
}
/*
we limit inputs to between 700usec and 2300usec. This allows us
to decode SBUS on the same pin, as SBUS will have a maximum
pulse width of 100usec
*/
if (width_usec > 700 && width_usec < 2300) {
// take a reading for the current channel
// buffer these
ppm_state._pulse_capt[ppm_state._channel_counter] = width_usec;
// move to next channel
ppm_state._channel_counter++;
}
// if we have reached the maximum supported channels then
// mark as unsynchronised, so we wait for a wide pulse
if (ppm_state._channel_counter >= LINUX_RC_INPUT_NUM_CHANNELS) {
for (uint8_t i=0; i<ppm_state._channel_counter; i++) {
_pwm_values[i] = ppm_state._pulse_capt[i];
}
_num_channels = ppm_state._channel_counter;
rc_input_count++;
ppm_state._channel_counter = -1;
}
}
/*
process a SBUS input pulse of the given width
*/
void RCInput::_process_sbus_pulse(uint16_t width_s0, uint16_t width_s1)
{
// convert to bit widths, allowing for up to 1usec error, assuming 100000 bps
uint16_t bits_s0 = (width_s0+1) / 10;
uint16_t bits_s1 = (width_s1+1) / 10;
uint16_t nlow;
uint8_t byte_ofs = sbus_state.bit_ofs/12;
uint8_t bit_ofs = sbus_state.bit_ofs%12;
if (bits_s0 == 0 || bits_s1 == 0) {
// invalid data
goto reset;
}
if (bits_s0+bit_ofs > 10) {
// invalid data as last two bits must be stop bits
goto reset;
}
// pull in the high bits
sbus_state.bytes[byte_ofs] |= ((1U<<bits_s0)-1) << bit_ofs;
sbus_state.bit_ofs += bits_s0;
bit_ofs += bits_s0;
// pull in the low bits
nlow = bits_s1;
if (nlow + bit_ofs > 12) {
nlow = 12 - bit_ofs;
}
bits_s1 -= nlow;
sbus_state.bit_ofs += nlow;
if (sbus_state.bit_ofs == 25*12 && bits_s1 > 12) {
// we have a full frame
uint8_t bytes[25];
uint8_t i;
for (i=0; i<25; i++) {
// get inverted data
uint16_t v = ~sbus_state.bytes[i];
// check start bit
if ((v & 1) != 0) {
goto reset;
}
// check stop bits
if ((v & 0xC00) != 0xC00) {
goto reset;
}
// check parity
uint8_t parity = 0, j;
for (j=1; j<=8; j++) {
parity ^= (v & (1U<<j))?1:0;
}
if (parity != (v&0x200)>>9) {
goto reset;
}
bytes[i] = ((v>>1) & 0xFF);
}
uint16_t values[LINUX_RC_INPUT_NUM_CHANNELS];
uint16_t num_values=0;
bool sbus_failsafe=false;
if (AP_RCProtocol_SBUS::sbus_decode(bytes, values, &num_values,
sbus_failsafe,
LINUX_RC_INPUT_NUM_CHANNELS) &&
num_values >= MIN_NUM_CHANNELS) {
for (i=0; i<num_values; i++) {
_pwm_values[i] = values[i];
}
_num_channels = num_values;
if (!sbus_failsafe) {
rc_input_count++;
}
}
goto reset;
} else if (bits_s1 > 12) {
// break
goto reset;
}
return;
reset:
memset(&sbus_state, 0, sizeof(sbus_state));
}
void RCInput::_process_dsm_pulse(uint16_t width_s0, uint16_t width_s1)
{
// convert to bit widths, allowing for up to 1usec error, assuming 115200 bps
uint16_t bits_s0 = ((width_s0+4)*(uint32_t)115200) / 1000000;
uint16_t bits_s1 = ((width_s1+4)*(uint32_t)115200) / 1000000;
uint8_t bit_ofs, byte_ofs;
uint16_t nbits;
if (bits_s0 == 0 || bits_s1 == 0) {
// invalid data
goto reset;
}
byte_ofs = dsm_state.bit_ofs/10;
bit_ofs = dsm_state.bit_ofs%10;
if(byte_ofs > 15) {
// invalid data
goto reset;
}
// pull in the high bits
nbits = bits_s0;
if (nbits+bit_ofs > 10) {
nbits = 10 - bit_ofs;
}
dsm_state.bytes[byte_ofs] |= ((1U<<nbits)-1) << bit_ofs;
dsm_state.bit_ofs += nbits;
bit_ofs += nbits;
if (bits_s0 - nbits > 10) {
if (dsm_state.bit_ofs == 16*10) {
// we have a full frame
uint8_t bytes[16];
uint8_t i;
for (i=0; i<16; i++) {
// get raw data
uint16_t v = dsm_state.bytes[i];
// check start bit
if ((v & 1) != 0) {
goto reset;
}
// check stop bits
if ((v & 0x200) != 0x200) {
goto reset;
}
bytes[i] = ((v>>1) & 0xFF);
}
uint16_t values[8];
uint16_t num_values=0;
if (dsm_decode(AP_HAL::micros64(), bytes, values, &num_values, 8) &&
num_values >= MIN_NUM_CHANNELS) {
for (i=0; i<num_values; i++) {
_pwm_values[i] = values[i];
}
_num_channels = num_values;
rc_input_count++;
}
}
memset(&dsm_state, 0, sizeof(dsm_state));
}
byte_ofs = dsm_state.bit_ofs/10;
bit_ofs = dsm_state.bit_ofs%10;
if (bits_s1+bit_ofs > 10) {
// invalid data
goto reset;
}
// pull in the low bits
dsm_state.bit_ofs += bits_s1;
return;
reset:
memset(&dsm_state, 0, sizeof(dsm_state));
}
void RCInput::_process_pwm_pulse(uint16_t channel, uint16_t width_s0, uint16_t width_s1)
{
if (channel < _num_channels) {
_pwm_values[channel] = width_s1; // range: 700usec ~ 2300usec
rc_input_count++;
}
}
/*
process a RC input pulse of the given width
*/
void RCInput::_process_rc_pulse(uint16_t width_s0, uint16_t width_s1)
{
#if 0
// useful for debugging
static FILE *rclog;
if (rclog == nullptr) {
rclog = fopen("/tmp/rcin.log", "w");
}
if (rclog) {
fprintf(rclog, "%u %u\n", (unsigned)width_s0, (unsigned)width_s1);
}
#endif
// treat as PPM-sum
_process_ppmsum_pulse(width_s0 + width_s1);
// treat as SBUS
_process_sbus_pulse(width_s0, width_s1);
// treat as DSM
_process_dsm_pulse(width_s0, width_s1);
}
/*
* Update channel values directly
*/
void RCInput::_update_periods(uint16_t *periods, uint8_t len)
{
if (len > LINUX_RC_INPUT_NUM_CHANNELS) {
len = LINUX_RC_INPUT_NUM_CHANNELS;
}
for (unsigned int i=0; i < len; i++) {
_pwm_values[i] = periods[i];
}
_num_channels = len;
rc_input_count++;
}