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ardupilot/libraries/AP_HAL_F4Light/RC_PPM_parser.cpp

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/*
(c) 2017 night_ghost@ykoctpa.ru
*/
#pragma GCC optimize ("O2")
#include <exti.h>
#include <timer.h>
#include "RCInput.h"
#include <pwm_in.h>
#include <AP_HAL/utility/dsm.h>
#include <AP_HAL/utility/sumd.h>
#include "sbus.h"
#include "GPIO.h"
#include "ring_buffer_pulse.h"
#include "RC_PPM_parser.h"
#include "UARTDriver.h"
#include "UART_PPM.h"
using namespace F4Light;
extern const AP_HAL::HAL& hal;
void PPM_parser::init(uint8_t ch){
memset((void *)&_val[0], 0, sizeof(_val));
_last_signal=0;
_last_change=0;
_channels=0;
channel_ctr=0;
_ch = ch + 1;
last_pulse = {0,0};
_ioc = Scheduler::register_io_completion(FUNCTOR_BIND_MEMBER(&PPM_parser::parse_pulses, void));
// TODO Panic on IOC not allocated ?
// callback is called on each edge so must be as fast as possible
Revo_handler h = { .mp = FUNCTOR_BIND_MEMBER(&PPM_parser::start_ioc, void) };
pwm_setHandler(h.h, _ch-1);
sbus_state[0].mode=BOARD_RC_SBUS;
sbus_state[1].mode=BOARD_RC_SBUS_NI;
}
void PPM_parser::start_ioc(void){
Scheduler::do_io_completion(_ioc);
}
void PPM_parser::parse_pulses(void){
if(_ch==0) return; // not initialized
Pulse p;
#if 0 // [ statistics to tune memory usage
uint16_t np = getPPM_count(_ch);
if(np>RCInput::max_num_pulses) RCInput::max_num_pulses=np;
#endif //]
while( getPPM_Pulse(&p, _ch-1)){
rxIntRC(last_pulse.length, p.length, p.state);
last_pulse = p;
}
}
void PPM_parser::rxIntRC(uint16_t last_value, uint16_t value, bool state)
{
if(state) { // was 1 so falling
if(_rc_mode==BOARD_RC_NONE){
_process_ppmsum_pulse( (last_value + value) >>1 ); // process PPM only if no protocols detected
}
if((_rc_mode & ~BOARD_RC_SBUS_NI) == 0){
// test for non-inverted SBUS in 2nd memory structures
_process_sbus_pulse(value>>1, last_value>>1, sbus_state[1]); // was 1 so now is length of 1, last is a length of 0
}
} else { // was 0 so rising
if((_rc_mode & ~BOARD_RC_SBUS) == 0){
// try treat as SBUS (inverted)
// SBUS protocols detection occures on the beginning of start bit of next frame
_process_sbus_pulse(value>>1, last_value>>1, sbus_state[0]); // was 0 so now is length of 0, last is a length of 1
}
if((_rc_mode & ~(BOARD_RC_DSM | BOARD_RC_SUMD)) == 0){
// try treat as DSM or SUMD. Detection occures on the end of stop bit
_process_dsm_pulse(value>>1, last_value>>1);
}
}
}
bool PPM_parser::_process_ppmsum_pulse(uint16_t value)
{
if (value >= 2700) { // Frame synchronization
if( channel_ctr >= F4Light_RC_INPUT_MIN_CHANNELS ) {
_channels = channel_ctr;
}
channel_ctr = 0;
_got_ppm=true;
return true;
} else if(value > 700 && value < 2300) {
if (channel_ctr < F4Light_RC_INPUT_NUM_CHANNELS) {
_last_signal = systick_uptime();
if(_val[channel_ctr] != value) _last_change = _last_signal;
_val[channel_ctr] = value;
channel_ctr++;
if (channel_ctr >= F4Light_RC_INPUT_NUM_CHANNELS) {
_channels = F4Light_RC_INPUT_NUM_CHANNELS;
}
}
return true;
} else { // try another protocols
return false;
}
}
/*
process a SBUS input pulse of the given width
pulses are captured on each edges and SBUS parser called on rising edge - beginning of start bit
*/
void PPM_parser::_process_sbus_pulse(uint16_t width_s0, uint16_t width_s1, F4Light::PPM_parser::SbusState &state)
{
// convert to bit widths, allowing for up to 4usec error, assuming 100000 bps - inverted
uint16_t bits_s0 = (width_s0+4) / 10;
uint16_t bits_s1 = (width_s1+4) / 10;
uint8_t byte_ofs = state.bit_ofs/12;
uint8_t bit_ofs = state.bit_ofs%12;
uint16_t nlow;
if (bits_s1 == 0 || bits_s0 == 0) { // invalid data
goto reset;
}
if (bits_s1+bit_ofs > 10) { // invalid data as last two bits must be stop bits
goto reset;
}
// pull in the high bits
state.bytes[byte_ofs] |= ((1U<<bits_s1)-1) << bit_ofs;
state.bit_ofs += bits_s1;
bit_ofs += bits_s1;
// pull in the low bits
nlow = bits_s0; // length of low bits
if (nlow + bit_ofs > 12) { // goes over byte boundary?
nlow = 12 - bit_ofs; // remaining part of byte
}
bits_s0 -= nlow; // zero bit residual
state.bit_ofs += nlow; // fill by zeros till byte end
if (state.bit_ofs == 25*12 && bits_s0 > 12) { // all frame got and was gap
// we have a full frame
uint8_t bytes[25];
uint16_t i;
for (i=0; i<25; i++) {
// get inverted data
uint16_t v = ~state.bytes[i];
if ((v & 1) != 0) { // check start bit
goto reset;
}
if ((v & 0xC00) != 0xC00) {// check stop bits
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[F4Light_RC_INPUT_NUM_CHANNELS];
uint16_t num_values=0;
bool sbus_failsafe=false, sbus_frame_drop=false;
if (sbus_decode(bytes, values, &num_values,
&sbus_failsafe, &sbus_frame_drop,
F4Light_RC_INPUT_NUM_CHANNELS) &&
num_values >= F4Light_RC_INPUT_MIN_CHANNELS)
{
for (i=0; i<num_values; i++) {
if(_val[i] != values[i]) _last_change = systick_uptime();
_val[i] = values[i];
}
_channels = num_values;
_rc_mode = state.mode; // lock input mode, SBUS has a parity and other checks so false positive is unreal
if (!sbus_failsafe) {
_got_dsm = true;
_last_signal = systick_uptime();
}
}
goto reset_ok;
} else if (bits_s0 > 12) { // Was inter-frame gap but not full frame
goto reset;
}
return;
reset:
reset_ok:
state.bit_ofs=0;
memset(&state.bytes, 0, sizeof(state.bytes));
}
/*
process a DSM satellite input pulse of the given width
pulses are captured on each edges and DSM parser called on falling edge - eg. beginning of start bit
*/
void PPM_parser::_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;
}
uint8_t bt= ((v>>1) & 0xFF);
bytes[i] = bt;
if(_rc_mode != BOARD_RC_DSM) {
// try to decode SUMD data on each byte, decoder butters frame itself.
uint16_t values[F4Light_RC_INPUT_NUM_CHANNELS];
uint8_t rssi;
uint8_t rx_count;
uint16_t channel_count;
if (sumd_decode(bt, &rssi, &rx_count, &channel_count, values, F4Light_RC_INPUT_NUM_CHANNELS) == 0) {
if (channel_count > F4Light_RC_INPUT_NUM_CHANNELS) {
continue;
}
_rc_mode = BOARD_RC_SUMD;
for (uint8_t j=0; j<channel_count; j++) {
if (values[j] != 0) {
if(_val[j] != values[j]) _last_change = systick_uptime();
_val[j] = values[j];
}
}
_channels = channel_count;
_last_signal = systick_uptime();
// _rssi = rssi;
}
}
if(_rc_mode == BOARD_RC_NONE) { // if protocol not decoded
UART_PPM::putch(bt, _ch); // push received bytes to memory queue to get via fake UARTs
}
}
if(_rc_mode != BOARD_RC_SUMD) { // try to decode buffer as DSM on full frame
uint16_t values[F4Light_RC_INPUT_NUM_CHANNELS];
uint16_t num_values=0;
if (dsm_decode(AP_HAL::micros64(), bytes, values, &num_values, F4Light_RC_INPUT_NUM_CHANNELS) &&
num_values >= F4Light_RC_INPUT_MIN_CHANNELS) {
_rc_mode = BOARD_RC_DSM; // lock input mode, DSM has a checksum so false positive is unreal
for (i=0; i<num_values; i++) {
if(_val[i] != values[i]) _last_change = systick_uptime();
_val[i] = values[i];
}
uint32_t nc=num_values+1;
if(nc>_channels)
_channels = nc;
_val[_channels-1]=bytes[0]; // rssi
_got_dsm = true;
_last_signal = systick_uptime();
}
}
}
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));
}
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