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Version v0.05f
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- Added missing Bluetooth OCXO warmup messages
- OCXO warmup now a separate function from calibration
- Added countdown for calibration
- Added selectable calibration countdowns (15s or 60s)
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@AndrewBCN
AndrewBCN committed Feb 21, 2022
1 parent 79061de commit 6602cfb
Showing 1 changed file with 106 additions and 31 deletions.
137 changes: 106 additions & 31 deletions software/GPSDO.ino
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/**********************************************************************************************************
STM32 GPSDO v0.05e by André Balsa, February 2022
STM32 GPSDO v0.05f by André Balsa, February 2022
GPLV3 license
Reuses small bits of the excellent GPS checker code Arduino sketch by Stuart Robinson - 05/04/20
From version 0.03 includes a command parser, so the GPSDO can receive commands from the USB serial or
Expand Down Expand Up @@ -126,7 +126,7 @@
// 2. Refactor the setup and main loop functions to make them as simple as possible.

#define Program_Name "GPSDO"
#define Program_Version "v0.05e"
#define Program_Version "v0.05f"
#define Author_Name "André Balsa"

// Debug options
Expand Down Expand Up @@ -391,17 +391,20 @@ volatile bool force_armpicDIV_flag = true; // indicates picDIV must be armed
volatile bool force_calibration_flag = true; // indicates GPSDO should start calibration sequence

volatile bool ocxo_needs_warming = true; // indicates OCXO needs to warm up a few minutes after power on

#ifdef FastBootMode
const uint16_t ocxo_warmup_time = 15; // ocxo warmup time in seconds; 15s for testing
const uint16_t ocxo_calib_time = 15; // 15s fast calibration countdown time (for each calibration step)
#else
const uint16_t ocxo_warmup_time = 300; // ocxo warmup time in seconds; 300s or 600s normal use
const uint16_t ocxo_calib_time = 60; // 60s normal calibration countdown time (for each calibration step)
#endif // FastBootMode

volatile bool tunnel_mode_flag = false; // the GPSDO relays the information directly to and from the GPS module to the USB serial
#ifdef TunnelModeTesting
const uint16_t tunnelSecs = 15; // tunnel mode timeout in seconds; 15s for testing, 300s or 600s normal use
#else
const uint16_t tunnelSecs = 300; // tunnel mode timeout in seconds; 15s for testing, 300s or 600s normal use
const uint16_t tunnelSecs = 300; // tunnel mode timeout in seconds; 15s for testing, 300s or 600s normal use
#endif // TunnelModeTesting

// Miscellaneous functions
Expand Down Expand Up @@ -880,10 +883,13 @@ boolean getUBX_ACK(uint8_t *MSG) {
}
#endif // UBX_CONFIG

// ---------------------------------------------------------------------------------------------
// GPSDO tunnel mode (GPS serial is relayed to Bluetooth serial or USB serial)
// ---------------------------------------------------------------------------------------------
void tunnelgps()
// GPSDO tunnel mode operation
{
#ifdef GPSDO_BLUETOOTH // print calibrating started message to either
#ifdef GPSDO_BLUETOOTH // print entering tunnel mode message to either
Serial2.println(); // Bluetooth serial xor USB serial
Serial2.print(F("Entering tunnel mode..."));
Serial2.println();
Expand All @@ -893,7 +899,7 @@ void tunnelgps()
Serial.println();
#endif // BLUETOOTH

// tunnel mode operation goes here
// tunnel mode operation starts here
uint32_t endtunnelmS = millis() + (tunnelSecs * 1000);
uint8_t GPSchar;
uint8_t PCchar;
Expand All @@ -902,17 +908,29 @@ void tunnelgps()
if (Serial1.available() > 0)
{
GPSchar = Serial1.read();
Serial.write(GPSchar); // echo NMEA stream to USB serial
#ifdef GPSDO_BLUETOOTH
Serial2.write(GPSchar); // echo GPS NMEA serial stream to Bluetooth serial
#else
Serial.write(GPSchar); // echo GPS NMEA serial stream to USB serial
#endif // BLUETOOTH
}
#ifdef GPSDO_BLUETOOTH
if (Serial2.available() > 0)
#else
if (Serial.available() > 0)
#endif // BLUETOOTH
{
#ifdef GPSDO_BLUETOOTH
PCchar = Serial2.read();
#else
PCchar = Serial.read();
Serial1.write(PCchar); // echo PC stream to GPS serial
#endif // BLUETOOTH
Serial1.write(PCchar); // echo USB serial stream to GPS serial
}
}
// tunnel mode operation ends here

#ifdef GPSDO_BLUETOOTH // print calibrating started message to either
#ifdef GPSDO_BLUETOOTH // print exiting tunnel mode message to either
Serial2.println(); // Bluetooth serial xor USB serial
Serial2.print(F("Tunnel mode exited."));
Serial2.println();
Expand All @@ -923,20 +941,21 @@ void tunnelgps()
#endif // BLUETOOTH

tunnel_mode_flag = false; // reset flag, exit tunnel mode
}
void docalibration()
// OCXO Vctl calibration routine: find an approximate value for Vctl
} // end of tunnel mode routine

// ---------------------------------------------------------------------------------------------
// OCXO warmup delay routine (only needed during a GPSDO "cold start")
// ---------------------------------------------------------------------------------------------
void doocxowarmup()
{
unsigned long startWarmup = millis(); // we need a rough timer
if (ocxo_needs_warming) {
// spend a few seconds/minutes here waiting for the OCXO to warm
// show countdown timer on OLED display
// and report on either USB serial or Bluetooth serial
// Note: during calibration the GPSDO does not accept any commands
uint16_t countdown = ocxo_warmup_time;
while (countdown) {
yellow_led_state = 2; // blink yellow LED

// spend a few seconds/minutes here waiting for the OCXO to warm
// show countdown timer on OLED display
// and report on either USB serial or Bluetooth serial
// Note: during warmup the GPSDO does not accept any commands
uint16_t countdown = ocxo_warmup_time;
while (countdown) {

#ifdef GPSDO_OLED
disp.clear(); // display warmup message on OLED
disp.setCursor(0, 0);
Expand Down Expand Up @@ -982,11 +1001,22 @@ void docalibration()
// do nothing for 1s
delay(1000);
countdown--;
}
ocxo_needs_warming = false; // reset flag, next "hot" calibration skips ocxo warmup
}
// proceed with calibration
#ifdef GPSDO_BLUETOOTH // print calibrating started message to either
ocxo_needs_warming = false; // reset flag, next "hot" calibration skips ocxo warmup
} // end of OCXO warmup routine

// ---------------------------------------------------------------------------------------------
// GPSDO calibration routine
// ---------------------------------------------------------------------------------------------
void docalibration()
// OCXO Vctl calibration: find an approximate value for Vctl
{
yellow_led_state = 2; // blink yellow LED (handled by 2Hz ISR)

if (ocxo_needs_warming) doocxowarmup();

// Note: during calibration the GPSDO does not accept any commands
#ifdef GPSDO_BLUETOOTH // print calibration started message to either
Serial2.println(); // Bluetooth serial xor USB serial
Serial2.print(F("Calibrating..."));
Serial2.println();
Expand Down Expand Up @@ -1039,27 +1069,56 @@ void docalibration()
// 1.5V for PWM = 65536 x (1.5 / 3.2) = 30720 results in frequency f1 = 10MHz + e1
// 2.5V for PWM = 65536 x (2.5 / 3.2) = 51200 results in frequency f2 = 10MHz + e2
// where f2 > f1 (most OCXOs have positive slope).

double f1, f2, e1, e2;

// make sure we have a fix and data
while (!cbTen_full) delay(1000);
while (!cbTen_full) delay(1000); // note there is a small chance that we lose PPS during calibration
// resulting in completely wrong calibration value

// measure frequency for Vctl=1.5V
Serial.println(F("set PWM 1.5V, wait 15s"));
Serial.println(F("Measure frequency for Vctl=1.5V"));
Serial.print(F("Set PWM Vctl to 1.5V, wait ")); Serial.print(ocxo_calib_time); Serial.println(F("s"));
analogWrite(VctlPWMOutputPin, 30720);
delay(15000);
Serial.print(F("f1 (average frequency for 1.5V Vctl): "));

uint16_t calib_countdown = ocxo_calib_time; // note there are two possible values depending on FastBootMode setting
while (calib_countdown > 0)
{
calib_countdown--;
Serial.print(calib_countdown); Serial.print(F("s "));
delay(1000);
}

Serial.println();
Serial.print(F("f1 (average frequency for Vctl=1.5V): "));
f1 = avgften;
Serial.print(f1,1);
Serial.println(F(" Hz"));
Serial.println();

// make sure we have a fix and data again
while (!cbTen_full) delay(1000);

// measure frequency for Vctl=2.5V
Serial.println(F("set PWM 2.5V, wait 15s"));
Serial.println(F("Measure frequency for Vctl=2.5V"));
Serial.println(F("Set PWM Vctl to 2.5V, wait ")); Serial.print(ocxo_calib_time); Serial.println(F("s"));
analogWrite(VctlPWMOutputPin, 51200);
delay(15000);

calib_countdown = ocxo_calib_time; // no need to declare variable again
while (calib_countdown > 0)
{
calib_countdown--;
Serial.print(calib_countdown); Serial.print(F("s "));
delay(1000);
}

Serial.println();
Serial.print(F("f2 (average frequency for 2.5V Vctl): "));
f2 = avgften;
Serial.print(f2,1);
Serial.println(F(" Hz"));
Serial.println();

// slope s is (f2-f1) / (51200-30720) for PWM
// So F=10MHz +/- 0.1Hz for PWM = 30720 - (e1 / s)
// set Vctl
Expand Down Expand Up @@ -1088,9 +1147,14 @@ void docalibration()
disp.fillScreen(ST7735_BLACK);
#endif // LCD_ST7735

yellow_led_state = 0; // turn off yellow LED (handled by 2Hz ISR)
force_calibration_flag = false; // reset flag, calibration done
} // end of docalibration()
} // end of GPSDO calibration routine


// ---------------------------------------------------------------------------------------------
// Adjust Vctl DAC routine
// ---------------------------------------------------------------------------------------------
#ifdef GPSDO_MCP4725
void adjustVctlDAC()
// This should reach a stable DAC output value / a stable 10000000.00 frequency
Expand Down Expand Up @@ -1123,6 +1187,9 @@ void adjustVctlDAC()
}
#endif // MCP4725

// ---------------------------------------------------------------------------------------------
// Adjust Vctl PWM routine
// ---------------------------------------------------------------------------------------------
#ifdef GPSDO_PWM_DAC
void adjustVctlPWM()
// This should reach a stable PWM output value / a stable 10000000.00 frequency
Expand Down Expand Up @@ -1748,6 +1815,9 @@ void uptimetostrings() {
}
}

// ---------------------------------------------------------------------------------------------
// setup routine, prepares the hardware for normal operation
// ---------------------------------------------------------------------------------------------
void setup()
{
// Wait 1 second for things to stabilize
Expand Down Expand Up @@ -1961,9 +2031,11 @@ void setup()
avgVcc = avg_adcVcc.reading(adcVcc);
# endif // VCC

#ifdef GPSDO_MCP4725
avg_dacVctl.begin();
dacVctl = analogRead(VctlInputPin);
avgdacVctl = avg_dacVctl.reading(dacVctl);
# endif // MCP4725

avg_pwmVctl.begin();
pwmVctl = analogRead(VctlPWMInputPin);
Expand All @@ -1974,6 +2046,9 @@ void setup()
// setup done
}

// ---------------------------------------------------------------------------------------------
// loop routine: this is the main loop
// ---------------------------------------------------------------------------------------------
void loop()
{
serial_commands_.ReadSerial(); // process any command from either USB serial (usually
Expand Down

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