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CrsfSerial.cpp
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CrsfSerial.cpp
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#include "CrsfSerial.h"
// static void hexdump(void *p, size_t len)
// {
// char *data = (char *)p;
// while (len > 0)
// {
// uint8_t linepos = 0;
// char* linestart = data;
// // Binary part
// while (len > 0 && linepos < 16)
// {
// if (*data < 0x0f)
// Serial.write('0');
// Serial.print(*data, HEX);
// Serial.write(' ');
// ++data;
// ++linepos;
// --len;
// }
// // Spacer to align last line
// for (uint8_t i = linepos; i < 16; ++i)
// Serial.print(" ");
// // ASCII part
// for (uint8_t i = 0; i < linepos; ++i)
// Serial.write((linestart[i] < ' ') ? '.' : linestart[i]);
// Serial.println();
// }
CrsfSerial::CrsfSerial(HardwareSerial &port, uint32_t baud) : _port(port), _crc(0xd5), _baud(baud),
_lastReceive(0), _lastChannelsPacket(0), _linkIsUp(false),
_passthroughMode(false)
{
// Crsf serial is 420000 baud for V2
_port.begin(_baud);
}
// Call from main loop to update
void CrsfSerial::loop()
{
handleSerialIn();
}
void CrsfSerial::handleSerialIn()
{
while (_port.available())
{
uint8_t b = _port.read();
_lastReceive = millis();
if (_passthroughMode)
{
if (onShiftyByte)
onShiftyByte(b);
continue;
}
_rxBuf[_rxBufPos++] = b;
handleByteReceived();
if (_rxBufPos == (sizeof(_rxBuf) / sizeof(_rxBuf[0])))
{
// Packet buffer filled and no valid packet found, dump the whole thing
_rxBufPos = 0;
}
}
checkPacketTimeout();
checkLinkDown();
}
void CrsfSerial::handleByteReceived()
{
bool reprocess;
do
{
reprocess = false;
if (_rxBufPos > 1)
{
uint8_t len = _rxBuf[1];
// Sanity check the declared length isn't outside Type + X{1,CRSF_MAX_PAYLOAD_LEN} + CRC
// assumes there never will be a CRSF message that just has a type and no data (X)
if (len < 3 || len > (CRSF_MAX_PAYLOAD_LEN + 2))
{
shiftRxBuffer(1);
reprocess = true;
}
else if (_rxBufPos >= (len + 2))
{
uint8_t inCrc = _rxBuf[2 + len - 1];
uint8_t crc = _crc.calc(&_rxBuf[2], len - 1);
if (crc == inCrc)
{
processPacketIn(len);
shiftRxBuffer(len + 2);
reprocess = true;
}
else
{
shiftRxBuffer(1);
reprocess = true;
}
} // if complete packet
} // if pos > 1
} while (reprocess);
}
void CrsfSerial::checkPacketTimeout()
{
// If we haven't received data in a long time, flush the buffer a byte at a time (to trigger shiftyByte)
if (_rxBufPos > 0 && millis() - _lastReceive > CRSF_PACKET_TIMEOUT_MS)
while (_rxBufPos)
shiftRxBuffer(1);
}
void CrsfSerial::checkLinkDown()
{
if (_linkIsUp && millis() - _lastChannelsPacket > CRSF_FAILSAFE_STAGE1_MS)
{
if (onLinkDown)
onLinkDown();
_linkIsUp = false;
}
}
void CrsfSerial::processPacketIn(uint8_t len)
{
const crsf_header_t *hdr = (crsf_header_t *)_rxBuf;
if (hdr->device_addr == CRSF_ADDRESS_FLIGHT_CONTROLLER)
{
switch (hdr->type)
{
case CRSF_FRAMETYPE_GPS:
packetGps(hdr);
break;
case CRSF_FRAMETYPE_RC_CHANNELS_PACKED:
packetChannelsPacked(hdr);
break;
case CRSF_FRAMETYPE_LINK_STATISTICS:
packetLinkStatistics(hdr);
break;
}
} // CRSF_ADDRESS_FLIGHT_CONTROLLER
}
// Shift the bytes in the RxBuf down by cnt bytes
void CrsfSerial::shiftRxBuffer(uint8_t cnt)
{
// If removing the whole thing, just set pos to 0
if (cnt >= _rxBufPos)
{
_rxBufPos = 0;
return;
}
if (cnt == 1 && onShiftyByte)
onShiftyByte(_rxBuf[0]);
// Otherwise do the slow shift down
uint8_t *src = &_rxBuf[cnt];
uint8_t *dst = &_rxBuf[0];
_rxBufPos -= cnt;
uint8_t left = _rxBufPos;
while (left--)
*dst++ = *src++;
}
void CrsfSerial::packetChannelsPacked(const crsf_header_t *p)
{
crsf_channels_t *ch = (crsf_channels_t *)&p->data;
_channels[0] = ch->ch0;
_channels[1] = ch->ch1;
_channels[2] = ch->ch2;
_channels[3] = ch->ch3;
_channels[4] = ch->ch4;
_channels[5] = ch->ch5;
_channels[6] = ch->ch6;
_channels[7] = ch->ch7;
_channels[8] = ch->ch8;
_channels[9] = ch->ch9;
_channels[10] = ch->ch10;
_channels[11] = ch->ch11;
_channels[12] = ch->ch12;
_channels[13] = ch->ch13;
_channels[14] = ch->ch14;
_channels[15] = ch->ch15;
for (unsigned int i = 0; i < CRSF_NUM_CHANNELS; ++i)
_channels[i] = map(_channels[i], CRSF_CHANNEL_VALUE_1000, CRSF_CHANNEL_VALUE_2000, 1000, 2000);
if (!_linkIsUp && onLinkUp)
onLinkUp();
_linkIsUp = true;
_lastChannelsPacket = millis();
if (onPacketChannels)
onPacketChannels();
}
void CrsfSerial::packetLinkStatistics(const crsf_header_t *p)
{
const crsfLinkStatistics_t *link = (crsfLinkStatistics_t *)p->data;
memcpy(&_linkStatistics, link, sizeof(_linkStatistics));
if (onPacketLinkStatistics)
onPacketLinkStatistics(&_linkStatistics);
}
void CrsfSerial::packetGps(const crsf_header_t *p)
{
const crsf_sensor_gps_t *gps = (crsf_sensor_gps_t *)p->data;
_gpsSensor.latitude = be32toh(gps->latitude);
_gpsSensor.longitude = be32toh(gps->longitude);
_gpsSensor.groundspeed = be16toh(gps->groundspeed);
_gpsSensor.heading = be16toh(gps->heading);
_gpsSensor.altitude = be16toh(gps->altitude);
_gpsSensor.satellites = gps->satellites;
if (onPacketGps)
onPacketGps(&_gpsSensor);
}
void CrsfSerial::write(uint8_t b)
{
_port.write(b);
}
void CrsfSerial::write(const uint8_t *buf, size_t len)
{
_port.write(buf, len);
}
void CrsfSerial::queuePacket(uint8_t addr, uint8_t type, const void *payload, uint8_t len)
{
if (!_linkIsUp)
return;
if (_passthroughMode)
return;
if (len > CRSF_MAX_PAYLOAD_LEN)
return;
uint8_t buf[CRSF_MAX_PACKET_SIZE];
buf[0] = addr;
buf[1] = len + 2; // type + payload + crc
buf[2] = type;
memcpy(&buf[3], payload, len);
buf[len + 3] = _crc.calc(&buf[2], len + 1);
// Busywait until the serial port seems free
// while (millis() - _lastReceive < 2)
// loop();
write(buf, len + 4);
}
void CrsfSerial::setPassthroughMode(bool val, unsigned int baud)
{
_passthroughMode = val;
_port.flush();
if (baud != 0)
_port.begin(baud);
else
_port.begin(_baud);
}