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Code for 'Smart Regulator' featured in 'Model Engineer', November 2020 on. Contains all work to August 2020 including all code described. Top level algorithm development is quite spares, leaving some work for you! Any questions - jon@jons-workshop.com
Dependencies: mbed BufferedSerial Servo2 PCT2075 I2CEeprom FastPWM
main.cpp
- Committer:
- JonFreeman
- Date:
- 2019-06-28
- Revision:
- 0:77803b3ee157
- Child:
- 1:450090bdb6f4
File content as of revision 0:77803b3ee157:
#include "mbed.h" #include "Alternator.h" #define MAGNETO_SPEED // Selects engine speed input as magneto coil on engine switch line #define SPEED_CONTROL_ENABLE // Includes engine revs servo control loop /* Alternator Regulator Jon Freeman June 2019 WHAT THIS PROGRAMME DOES - BEGIN Loop forever at 32 Hz { Read engine RPM Adjust Alternator field current max limit according to RPM Measure system voltage (just in case this is ever useful) Respond to any commands arriving at serial port (setup and test link to laptop) Flash LED at 8 Hz as proof of life } END INPUTS AnalogIn x 2 - Ammeter chip - current and offset AnalogIns INPUT AnalogIn - System voltage for info only. INPUT AnalogIn - ExtRevDemand INPUT AnalogIn - DriverPot INPUT Pulse engine speed indicator, speed checked against EEPROM data to select max pwm duty ratio for this speed INPUT Final pwm gate drive wired back to InterruptIn ** MAYBE USEFUL OR NOT ** Could read this back via serial to laptop OUTPUT pwm to MCP1630. This is clock to pwm chip. Also limits max duty ratio RS232 serial via USB to setup eeprom data */ // Uses software bit banged I2C - DONE (because no attempt to get I2C working on these small boards) /** * Jumpers fitted to small mbed Nucleo boards - D5 - A5 and D4 - A4 CHECK - yes */ /* declared in file i2c_bit_banged.cpp DigitalInOut SDA (D4); // Horrible bodge to get i2c working using bit banging. DigitalInOut SCL (D5); // DigitalInOut do not work as you might expect. Fine if used only as OpenDrain opuputs though! DigitalIn SDA_IN (A4); // That means paralleling up with two other pins as inputs DigitalIn SCL_IN (A5); // This works but is a pain. Inbuilt I2C should have worked but never does on small boards with 32 pin cpu. */ Serial pc (USBTX, USBRX); // Comms port to pc or terminal using USB lead BufferedSerial LocalCom (PA_9, PA_10); // New March 2019 // Above combo of Serial and BufferedSerial is the only one to work ! // INPUTS : AnalogIn Ain_SystemVolts (A0); // Brought out to CN8 'AN' A0. Connect 3k3 resistor from A0 to ground. AnalogIn Ammeter_In (A1); // Output of ASC709LLFTR ammeter chip (pin 20) AnalogIn Ammeter_Ref (A6); // Ref output from ASC709LLFTR used to set ammeter zero (pin 25) AnalogIn Ext_Rev_Demand (D3); // Servo determines engine revs, servo out to be higher of Ext_Rev_Demand and internal calc AnalogIn Driver_Pot (A3); // If whole control system can be made to fit // Connect 33k resistor from A0 to nom 24 Volt system rail. //#ifdef TARGET_NUCLEO_F303K8 // #ifdef TARGET_NUCLEO_L432KC // /* MODULE PIN USAGE 1 PA_9 D1 LocalCom Tx 2 PA_10 D0 LocalCom Rx 3 NRST 4 GND 5 PA12_D2 NEW June 2019 - Output engine tacho cleaned-up 6 PB_0 D3 AnalogIn Ext_Rev_Demand 7 PB_7 D4 SDA i2c to 24LC memory 8 PB_6 D5 SCL i2c to 24LC memory 9 PB_12 D6 PwmOut PWM_OSC_IN Timebase for pwm, also determines max duty ratio 10 N.C. 11 N.C. 12 PA_8 D9 InterruptIn pulse_tacho from alternator, used to measure rpm 13 PA_11 D10 14 PB_5 D11 15 PB_4 D12 16 PB_3 D13 LED Onboard LED 17 3V3 18 AREF 19 PA_0 A0 AnalogIn V_Sample system link voltage 20 PA_1 A1 AnalogIn Ammeter_In 21 PA_3 A2 PWM analogue out 22 PA_4 A3 InterruptIn VEXT PWM controller output folded back for cpu to monitor, useful on test to read what pwm required to do what 23 PA_5 A4 n.c. SDA_IN paralleled to i2c pin, necessary because i2c has to be bit banged 24 PA_6 A5 n.c. SCL_IN paralleled to i2c pin, necessary because i2c has to be bit banged 25 PA_7 A6 AnalogIn Ammeter_Ref 26 PA_2 A7 UART2_TX Throttle Servo out now on D10, can not use D11, can not use D12 for these 27 5V 28 NRST 29 GND 30 VIN */ InterruptIn pulse_tacho (D9); // Signal from 'W' alternator terminal via low pass filter and Schmitt trigger cleanup // NOTE D7 pin was no good for this //InterruptIn VEXT (A3); // PWM controller output folded back for cpu to monitor, useful on test to read what pwm required to do what InterruptIn VEXT (D11); // PWM controller output folded back for cpu to monitor, useful on test to read what pwm required to do what // OUTPUTS : //DigitalOut Scope_probe (D0); // Handy pin to hang scope probe onto while developing code DigitalOut myled(LED1); // Green LED on board is PB_3 D13 //PwmOut PWM_OSC_IN (A6); // Can alter prescaler can not use A5 PwmOut PWM_OSC_IN (D6); // Can alter prescaler can not use A5 PwmOut A_OUT (A2); // Can alter prescaler can not use A5 //Servo Throttle (A2); // Pin A2, PA3 //Servo Throttle (A7); // Changed from A2, June 2019 Servo Throttle (D10); // Changed from A2, June 2019 DigitalOut EngineTachoOut (D2); // New June 2019 #endif Timer microsecs; Ticker loop_timer; // Device to cause periodic interrupts, used to sync iterations of main programme loop - slow extern eeprom_settings mode ; // SYSTEM CONSTANTS /* Please Do Not Alter these */ const int MAIN_LOOP_REPEAT_TIME_US = 31250; // 31250 us, with TACHO_TAB_SIZE = 32 means tacho_ticks_per_time is tacho_ticks_per_second const int MAIN_LOOP_ITERATION_Hz = 1000000 / MAIN_LOOP_REPEAT_TIME_US; // = 32 Hz //const int FAST_INTERRUPT_RATE = 3125; /* End of Please Do Not Alter these */ /* Global variable declarations */ uint32_t //semaphore = 0, volt_reading = 0, // Global updated by interrupt driven read of Battery Volts amp_reading = 0, amp_offset = 0, ext_rev_req = 0, driver_reading = 0, tacho_count = 0, // Global incremented on each transition of InterruptIn pulse_tacho tacho_ticks_per_time = 0, // Global tacho ticks in most recent (MAIN_LOOP_REPEAT_TIME_US * TACHO_TABLE_SIZE) micro secs sys_timer32Hz = 0; // gets incremented by our Ticker ISR every MAIN_LOOP_REPEAT_TIME_US bool loop_flag = false; // made true in ISR_loop_timer, picked up and made false again in main programme loop bool flag_8Hz = false; // As loop_flag but repeats 8 times per sec const double scale = 0.125; const double shrink_by = 1.0 - scale; double glob_rpm; /* End of Global variable declarations */ //void ISR_fast_interrupt () { // here at 10 times main loop repeat rate (i.e. 320Hz) void ISR_fast_interrupt () { // here at ** 25 ** times main loop repeat rate (1250us, i.e. 800Hz) static int t = 0; switch (t) { case 0: volt_reading >>= 1; // Result = Result / 2 volt_reading += Ain_SystemVolts.read_u16 (); // Result = Result + New Reading break; case 1: amp_reading >>= 1; // Result = Result / 2 amp_reading = Ammeter_In.read_u16(); break; case 2: amp_offset >>= 1; // Result = Result / 2 amp_offset = Ammeter_Ref.read_u16(); break; case 3: ext_rev_req >>= 1; // Result = Result / 2 ext_rev_req = Ext_Rev_Demand.read_u16(); break; case 4: driver_reading >>= 1; // Result = Result / 2 driver_reading = Driver_Pot.read_u16(); break; case 5: // semaphore++; const int TACHO_TABLE_SIZE = MAIN_LOOP_ITERATION_Hz; // Ensures table contains exactly one seconds worth of samples static uint32_t h[TACHO_TABLE_SIZE], // circular buffer to contain list of 'tacho_count's i = 0, last_temp = 0; static double rpm_filt = 0.0; double tmp; uint32_t temp = tacho_count; // Read very latest total pulse count from global tacho_count tmp = (double) (temp - last_temp); last_temp = temp; #ifdef MAGNETO_SPEED tmp *= (scale * 32.0 * 60.0); // ???? Is this including alternator poles count ??? Do we need MAGNETO_SPEED included #else tmp *= (scale * 32.0 * 60.0 / 12.0); // ???? Is this including alternator poles count ??? Do we need MAGNETO_SPEED included #endif rpm_filt *= shrink_by; rpm_filt += tmp; glob_rpm = rpm_filt; tacho_ticks_per_time = temp - h[i]; // latest tacho total pulse count - oldest stored tacho total pulse count h[i] = temp; // latest overwrites oldest in table i++; // index to next table position for next time around if (i >= TACHO_TABLE_SIZE) i = 0; // circular buffer loop_flag = true; // set flag to allow main programme loop to proceed sys_timer32Hz++; // Just a handy measure of elapsed time for anything to use if ((sys_timer32Hz & 0x03) == 0) flag_8Hz = true; // flag gets set 8 times per sec. Other code may clear flag and make use of this break; } t++; if (t > 9) t = 0; } /** void ISR_loop_timer () * This ISR responds to Ticker interrupts at a rate of (probably) 32 times per second (check from constant declarations above) * This ISR sets global flag 'loop_flag' used to synchronise passes around main programme control loop. * Also, updates global int 'tacho_ticks_per_time' to contain total number of transitions from alternator 'W' terminal in * time period from exactly one second ago until now. * Increments global 'sys_timer32Hz', usable anywhere as general measure of elapsed time */ void ISR_loop_timer () // This is Ticker Interrupt Service Routine - loop timer - MAIN_LOOP_REPEAT_TIME_US { // Jan 2019 MAIN_LOOP_REPEAT_TIME_US = 31.25 ms const int TACHO_TABLE_SIZE = MAIN_LOOP_ITERATION_Hz; // Ensures table contains exactly one seconds worth of samples static uint32_t h[TACHO_TABLE_SIZE], // circular buffer to contain list of 'tacho_count's i = 0, last_temp = 0; static double rpm_filt = 0.0; double tmp; uint32_t temp = tacho_count; // Read very latest total pulse count from global tacho_count tmp = (double) (temp - last_temp); last_temp = temp; #ifdef MAGNETO_SPEED tmp *= (scale * 32.0 * 60.0); // ???? Is this including alternator poles count ??? Do we need MAGNETO_SPEED included #else tmp *= (scale * 32.0 * 60.0 / 12.0); // ???? Is this including alternator poles count ??? Do we need MAGNETO_SPEED included #endif // tmp *= (scale * 32.0 * 60.0 / 12.0); rpm_filt *= shrink_by; rpm_filt += tmp; glob_rpm = rpm_filt; tacho_ticks_per_time = temp - h[i]; // latest tacho total pulse count - oldest stored tacho total pulse count h[i] = temp; // latest overwrites oldest in table i++; // index to next table position for next time around if (i >= TACHO_TABLE_SIZE) i = 0; // circular buffer loop_flag = true; // set flag to allow main programme loop to proceed sys_timer32Hz++; // Just a handy measure of elapsed time for anything to use if ((sys_timer32Hz & 0x03) == 0) flag_8Hz = true; // flag gets set 8 times per sec. Other code may clear flag and make use of this } // New stuff June 2019 //uint32_t magneto_count = 0; #ifdef MAGNETO_SPEED bool magneto_stretch = false; Timeout magneto_timo; uint32_t magneto_times[8] = {0,0,0,0,0,0,0,0}; void ISR_magneto_tacho () ; // New June 2019 // Engine On/Off switch turns engine off by shorting magneto to ground. // Therefore have pulse signal one pulse per rev (even tghough 4 stroke, spark delivered at 2 stroke rate) // Pulse spacing 20ms @ 3000 RPM, 60ms @ 1000 RPM, 6ms @ 10000 RPM // Relies also on a timeout void magneto_timeout () { magneto_stretch = false; // Magneto ringing finished by now, re-enable magneto pulse count EngineTachoOut = 0; } void ISR_magneto_tacho () // Here rising or falling edge of magneto output, not both { if (!magneto_stretch) { uint32_t new_time = microsecs.read_us(); if (new_time < magneto_times[1]) // rollover detection magneto_times[1] = 0; magneto_times[0] = new_time - magneto_times[1]; // microsecs between most recent two sparks magneto_times[1] = new_time; // actual time microsecs of most recent spark magneto_stretch = true; magneto_timo.attach_us (&magneto_timeout, 5000); // To ignore ringing and multiple counts on magneto output, all settled within about 5ms tacho_count++; EngineTachoOut = 1; } } #endif // Endof New stuff June 2019 //uint32_t time_diff; /** void ISR_pulse_tacho () * */ void ISR_pulse_tacho () // Interrupt Service Routine - here after each lo to hi and hi to lo transition on pulse_tacho pin { // static uint64_t ustot = 0; // uint64_t new_time = microsecs.read_high_resolution_us(); static uint32_t ustot = 0; uint32_t new_time = microsecs.read_us(); if (new_time < ustot) // rollover detection ustot = 0; //// time_diff = (uint32_t) new_time - ustot; // time_diff = new_time - ustot; // always 0 or positive ustot = new_time; tacho_count++; } uint32_t t_on = 0, t_off = 0, measured_pw_us = 0; int ver = 0, vef = 0; void ISR_VEXT_rise () // InterruptIn interrupt service { // Here is possible to read back how regulator has controlled pwm ver++; t_on = microsecs.read_us(); } void ISR_VEXT_fall () // InterruptIn interrupt service { vef++; t_off = microsecs.read_us(); measured_pw_us = t_off - t_on; } // **** End of Interrupt Service Routines **** /** uint32_t ReadEngineRPM () * System timers arranged such that tacho_ticks_per_time contains most up to the moment count of tacho ticks per second. * This * 60 / number of alternator poles gives Revs Per Minute * Band pass filter alternator phase output - LF rolloff about 50Hz, HF rolloff about 1500Hz */ uint32_t ReadEngineRPM () { #ifdef MAGNETO_SPEED uint32_t time_since_last_spark = microsecs.read_us() - magneto_times[1]; if (time_since_last_spark > 50000) // if engine probably stopped, return old method RPM return tacho_ticks_per_time * 60; // 1 pulse per rev from magneto return (60000000 / magneto_times[0]); // 60 million / microsecs between two most recent sparks #else return tacho_ticks_per_time * 60 / 12; // Numof alternator poles, 12, factored in. #endif } double Read_BatteryVolts () { return (double) volt_reading / 1626.0; // divisor fiddled to make voltage reading correct ! } void set_servo (double p) { // Only for test, called from cli Throttle = p; } double normalise (double * p) { if (*p > 0.999) *p = 0.999; if (*p < 0.001) *p = 0.001; return * p; } uint32_t RPM_demand = 0; // For test, set from cli void set_RPM_demand (uint32_t d) { if (d < 10) d = 10; if (d > 5600) d = 5600; RPM_demand = d; } extern void command_line_interpreter () ; // Comms with optional pc or device using serial port through board USB socket extern bool i2c_init () ; extern int check_24LC64 () ; // Programme Entry Point int main() { // local variable declarations double servo_position = 0.2; // set in speed control loop double revs_error; int irevs_error; int ticks = 0; const double throttle_limit = 0.4; loop_timer.attach_us (&ISR_loop_timer, MAIN_LOOP_REPEAT_TIME_US); // Start periodic interrupt generator #ifdef MAGNETO_SPEED pc.printf ("Magneto Mode\r\n"); pulse_tacho.fall (&ISR_magneto_tacho); // 1 pulse per engine rev #else pc.printf ("Alternator W signal Mode\r\n"); pulse_tacho.rise (&ISR_pulse_tacho); // Handles - Transition on filtered input version of alternator phase output pulse_tacho.fall (&ISR_pulse_tacho); // #endif VEXT.rise (&ISR_VEXT_rise); // Handles - MCP1630 has just turned mosfet on VEXT.fall (&ISR_VEXT_fall); // Handles - MCP1630 has just turned mosfet off microsecs.reset() ; // timer = 0 microsecs.start () ; // 64 bit, counts micro seconds and times out in half million years PWM_OSC_IN.period_us (PWM_PERIOD_US); // about 313Hz PWM_OSC_IN.pulsewidth_us (9); // value is int A_OUT.period_us (100); A_OUT.pulsewidth_us (19); Throttle = servo_position; pc.printf ("\r\n\n\n\n\nAlternator Regulator 2019, Jon Freeman, SystemCoreClock=%d\r\n", SystemCoreClock); if (!i2c_init()) pc.printf ("i2c bus failed init\r\n"); // end of local variable declarations pc.printf ("check_24LC64 returned 0x%x\r\n", check_24LC64()); mode.load () ; // Fetch values from eeprom, also builds table of speed -> pwm lookups // Setup Complete ! Can now start main control forever loop. //***** START OF MAIN LOOP while (1) { // Loop forever, repeats synchroised by waiting for ticker Interrupt Service Routine to set 'loop_flag' true while (!loop_flag) { // Most of the time is spent in this loop, repeatedly re-checking for commands from pc port command_line_interpreter () ; // Proceed beyond here once loop_timer ticker ISR has set loop_flag true } // Jan 2019 pass here 32 times per sec loop_flag = false; // Clear flag set by ticker interrupt handler #ifdef SPEED_CONTROL_ENABLE // uint32_t RPM_demand = 0; // For test, set from cli // double servo_position = 0.0; // set in speed control loop // double revs_error; // time_since_last_spark = microsecs.read_us() - magneto_times[1]; irevs_error = RPM_demand - ReadEngineRPM (); revs_error = (double) irevs_error; if (RPM_demand < 3000) servo_position = Throttle = 0.0; else { servo_position += (revs_error / 75000.0); servo_position = normalise(&servo_position); if (servo_position < 0.0 || servo_position > 1.0) pc.printf ("servo_position error %f\r\n", servo_position); if (servo_position > throttle_limit) servo_position = throttle_limit; Throttle = servo_position; } #endif PWM_OSC_IN.pulsewidth_us (mode.get_pwm((int)glob_rpm)); // Update field current according to latest measured RPM // while (LocalCom.readable()) { // int q = LocalCom.getc(); // //q++; // pc.putc (q); // } if (flag_8Hz) { // Do any stuff to be done 8 times per second flag_8Hz = false; myled = !myled; LocalCom.printf ("%d\r\n", volt_reading); ticks++; if (ticks > 7) { // once per sec stuff ticks = 0; pc.printf ("RPM %d, err %.1f, s_p %.2f\r\n", ReadEngineRPM (), revs_error, servo_position); } // eo once per second stuff } // End of if(flag_8Hz) } // End of main programme loop } // End of main function - end of programme //***** END OF MAIN LOOP