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Optimise GPS Baud Rate cycle
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Previously, our baud rate cycled through one list twice.

There were some rarer baudrates in there, so this code
separates out those into a dedicated list that is only
run through if detection fails for common bauds. We also
only run through each baud rate once.
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fifieldt committed Oct 21, 2024
1 parent a4705d2 commit 9656aa4
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Showing 2 changed files with 39 additions and 22 deletions.
56 changes: 36 additions & 20 deletions src/gps/GPS.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -420,21 +420,34 @@ bool GPS::setup()
if (tx_gpio && gnssModel == GNSS_MODEL_UNKNOWN) {

// if GPS_BAUDRATE is specified in variant (i.e. not 9600), skip to the specified rate.
if (speedSelect == 0 && GPS_BAUDRATE != serialSpeeds[speedSelect]) {
if (probeTries == 0 && GPS_BAUDRATE != 9600) {
speedSelect = std::find(serialSpeeds, std::end(serialSpeeds), GPS_BAUDRATE) - serialSpeeds;
if (speedSelect == 0) {
speedSelect = std::find(rareSerialSpeeds, std::end(rareSerialSpeeds), GPS_BAUDRATE) - rareSerialSpeeds;
probeTries = 1;
}
}

LOG_DEBUG("Probing for GPS at %d", serialSpeeds[speedSelect]);
gnssModel = probe(serialSpeeds[speedSelect]);
if (gnssModel == GNSS_MODEL_UNKNOWN) {
if (++speedSelect == sizeof(serialSpeeds) / sizeof(int)) {
speedSelect = 0;
if (--probeTries == 0) {
if (probeTries == 0) {
LOG_DEBUG("Probing for GPS at %d", serialSpeeds[speedSelect]);
gnssModel = probe(serialSpeeds[speedSelect]);
if (gnssModel == GNSS_MODEL_UNKNOWN) {
if (++speedSelect == sizeof(serialSpeeds) / sizeof(int)) {
speedSelect = 0;
++probeTries;
}
}
}
// Rare Serial Speeds
if (probeTries == 1) {
LOG_DEBUG("Probing for GPS at %d", rareSerialSpeeds[speedSelect]);
gnssModel = probe(rareSerialSpeeds[speedSelect]);
if (gnssModel == GNSS_MODEL_UNKNOWN) {
if (++speedSelect == sizeof(rareSerialSpeeds) / sizeof(int)) {
LOG_WARN("Giving up on GPS probe and setting to 9600.");
return true;
}
return false;
}
return false;
}
} else {
gnssModel = GNSS_MODEL_UNKNOWN;
Expand Down Expand Up @@ -662,7 +675,8 @@ bool GPS::setup()
SEND_UBX_PACKET(0x06, 0x8A, _message_VALSET_DISABLE_SBAS_BBR, "disable SBAS M10 GPS BBR", 300);
delay(750); // will cause a receiver restart so wait a bit

// Done with initialization, Now enable wanted NMEA messages in BBR layer so they will survive a periodic sleep.
// Done with initialization, Now enable wanted NMEA messages in BBR layer so they will survive a periodic
// sleep.
SEND_UBX_PACKET(0x06, 0x8A, _message_VALSET_ENABLE_NMEA_BBR, "enable messages for M10 GPS BBR", 300);
delay(750);
// Next enable wanted NMEA messages in RAM layer
Expand Down Expand Up @@ -924,10 +938,10 @@ void GPS::down()
#endif

if (softsleepSupported) {
// How long does gps_update_interval need to be, for GPS_HARDSLEEP to become more efficient than GPS_SOFTSLEEP?
// Heuristic equation. A compromise manually fitted to power observations from U-blox NEO-6M and M10050
// https://www.desmos.com/calculator/6gvjghoumr
// This is not particularly accurate, but probably an impromevement over a single, fixed threshold
// How long does gps_update_interval need to be, for GPS_HARDSLEEP to become more efficient than
// GPS_SOFTSLEEP? Heuristic equation. A compromise manually fitted to power observations from U-blox NEO-6M
// and M10050 https://www.desmos.com/calculator/6gvjghoumr This is not particularly accurate, but probably an
// impromevement over a single, fixed threshold
uint32_t hardsleepThreshold = (2750 * pow(predictedSearchDuration / 1000, 1.22));
LOG_DEBUG("gps_update_interval >= %us needed to justify hardsleep", hardsleepThreshold / 1000);

Expand Down Expand Up @@ -1279,10 +1293,12 @@ GPS *GPS::createGps()

if (!GPS_EN_ACTIVE) { // Need to invert the pin before hardware
new GpioNotTransformer(
virtPin, p); // We just leave this created object on the heap so it can stay watching virtPin and driving en_gpio
virtPin,
p); // We just leave this created object on the heap so it can stay watching virtPin and driving en_gpio
} else {
new GpioUnaryTransformer(
virtPin, p); // We just leave this created object on the heap so it can stay watching virtPin and driving en_gpio
virtPin,
p); // We just leave this created object on the heap so it can stay watching virtPin and driving en_gpio
}
}

Expand Down Expand Up @@ -1390,8 +1406,8 @@ bool GPS::factoryReset()
_serial_gps->write("$PMTK104*37\r\n");
// No PMTK_ACK for this command.
delay(100);
// send the UBLOX Factory Reset Command regardless of detect state, something is very wrong, just assume it's UBLOX.
// Factory Reset
// send the UBLOX Factory Reset Command regardless of detect state, something is very wrong, just assume it's
// UBLOX. Factory Reset
byte _message_reset[] = {0xB5, 0x62, 0x06, 0x09, 0x0D, 0x00, 0xFF, 0xFB, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0x17, 0x2B, 0x7E};
_serial_gps->write(_message_reset, sizeof(_message_reset));
Expand Down Expand Up @@ -1430,8 +1446,8 @@ bool GPS::lookForTime()
auto d = reader.date;
if (ti.isValid() && d.isValid()) { // Note: we don't check for updated, because we'll only be called if needed
/* Convert to unix time
The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970
(midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z).
The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1,
1970 (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z).
*/
struct tm t;
t.tm_sec = ti.second() + round(ti.age() / 1000);
Expand Down
5 changes: 3 additions & 2 deletions src/gps/GPS.h
Original file line number Diff line number Diff line change
Expand Up @@ -75,13 +75,14 @@ class GPS : private concurrency::OSThread
uint8_t fixType = 0; // fix type from GPGSA
#endif
private:
const int serialSpeeds[6] = {9600, 115200, 38400, 4800, 57600, 9600};
const int serialSpeeds[6] = {9600, 115200, 38400};
const int rareSerialSpeeds[6] = {4800, 57600, 9600};
uint32_t lastWakeStartMsec = 0, lastSleepStartMsec = 0, lastFixStartMsec = 0;
uint32_t rx_gpio = 0;
uint32_t tx_gpio = 0;

int speedSelect = 0;
int probeTries = 2;
int probeTries = 0;

/**
* hasValidLocation - indicates that the position variables contain a complete
Expand Down

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