Andrew R
Power control and management
Diff: main.cpp
- Revision:
- 2:c449cfb7752c
- Parent:
- 0:36494271e31a
--- a/main.cpp Thu Feb 16 13:39:39 2017 +0000
+++ b/main.cpp Thu Nov 10 11:11:58 2022 +0000
@@ -2,125 +2,121 @@
/* Andrew C. Russell (c) 2015 */
/* The controller pin definitions are set in Pindef1114.h file. */
/* The main loop is driven by an interrupt on ACDET1 - 16.66ms for 60 Hz and 20ms for 50 Hz */
-/* The WDT is set for a 25ms timeout. If AC power is removed, the SPKR and INRUSH outputs */
-/* are driven LOW immediately. The power supply to the uC is supported by a 100uF 6.3V */
-/* capacityor to facilitate this. If the ERROR input goes LOW after power-up cycle, the */
+/* The WDT is set for a 25ms timeout. If AC power is removed, the MCU resets in 25ms */
+/* and all relays de-energized. If the ERROR input goes LOW after power-up cycle, the */
/* program disconnects the speaker. During the power up cycle - 150 mains cycles for */
-/* pre-charge and 150 mains cycles for the output to DC settle - and whenever an error */
+/* pre-charge and 250 mains cycles for the output to DC settle - and whenever an error */
/* condition is encountered, the power LED is flashed at 0.5 Hz */
/* The latency between the loss of ACDET1 and the SPKR being disengaged is ~25ms */
-/* Note that if the TRIGGER input is used, the +12V actually powers up the controller */
-/* which then bootstraps itself by applying AC power via the PWR_R */
+/* Provision for two 10k NTC thermistor sensors is also provided. The NTC is in the lower */
+/* leg of a divider with the upper leg a 10k resistor. The trip temp (TRIPON), */
+/* reset temp (TRIPOFF) and the temperature alarm (TEMPHIGH) are directly set in Volts */
+/* A low on the clip input will cause the clip LED to flash on for 1s. Note CLIP has to */
+/* recycle HIGH and then LOW again to retrigger the CLIP output - it does not flash */
+/* continuosly if held LOW */
+/* Note: if the amp clips for too long, the DC offset interuppt will be triggered because */
+/* the clip input and the DC offset detect inputs are connected. */
#include "mbed.h"
-#include "WDT.h"
+#include "WDT.h" // Watch Dog Timer
#include "Pindef1114.h" // all microcontroller I/O pin assignments defined here
-#include "AnalogIn.h"
+#include "AnalogIn.h" // standard mbed supplied analog driver header file
+#include "math.h"
+
#define AC_LOSS 0.025 // this is the wdt set value in seconds
#define TRUE 1
#define FALSE 0
#define HIGH 1
#define LOW 0
-#define BAD 0
-#define OK 1
-#define INDIC 25 // the number of mains cycles between indicator lamp flip
-#define inrush_t 150 //# of mains cycles to wait before bypassing the NTC
+#define INDIC 25 // the number of mains cycles between LED illumination flip
+#define inrush_t 200 //# of mains cycles to wait before bypassing the NTC
#define amp_settle 300 //# of mains cycles to let amp module OP settle
-#define CLIP_ON 5 // the clip LED goes on for ACDET1 periodes
-#define TEMPHIGH 0.7 // temperature alarm
-#define TRIPON 0.83 // this is the trip temperature - 830mV = 65 deg C on LM60
-#define TRIPOFF 0.75 // this is the lower re-activate amplifier
- //temperature - ~59 deg C LM60
-
-int T1;
-int T2;
-int T3;
-int T4;
+#define CLIP_ON 20 // the clip LED goes on for n ACDET1 periods
+#define TEMPHIGH 65 // temperature alarm in Volts - 65 deg C
+#define TRIPON 70 // this is the trip temperature in volts - 70 deg C
+#define TRIPOFF 62 // this is the lower re-activate amplifier temperature in volts - 64 deg C
+
+//Following used in the calculation of temp in deg C from an NTC
+#define Vref 3.31 // this is the A-D reference voltage
+#define Ref 10000 // the upper reference resistor from VREF to the NTC [was 2.2k]
+#define To 298 // coefficiants required for Steinhart-Hart equation
+#define B 3900 // from NTC data sheet
+#define Ro 10000
+#define cal65 3.3 // cal out any error at 65deg C - determined by applying
+ // required offset at 65 deg C - so at 65C the temp is accurate
+
+#define e 2.718281828459
+
+int F1; // test flag used in trip() TRUE if overtemp has tripped
int mains_cnt; // mains cycle counter
-int FLAG1; // used to detect if we are in or out of power up process
-int FLAG_TRIGGER; // TRUE if power up was via the trigger input
+int FLAG1; // TRUE if power-up process is completed otherwise FALSE
int indi_flip; // counts mains cycles - used in indicator status
int clip_cnt; // ACDET1 int derived counter for the clip indicator
-float templ;
+float templ; // left and right channel temperature read in by A-D in deg C
float tempr;
-int temp_status;
-
-Ticker flipper; // this is the ACDET timer - runs at 13.2 or 20ms
-// ref 60 Hz or 50 Hz mains frequency
+float t_left;
+float t_right;
+Ticker flipper; // this is the ACDET1 WDT ticker timer
+
// declare function prototypes here
-void analog_input(void); // measure the temperature
-void output_clip(void); // clip indicator
-void indi_flash (void); // universal indicator flash
-void temp_trip (void); // action to be taken when overtemp
-void acdetect(void); // triggers the counter
+void trip(void); // assess what actions to take based on temperature
+void temp_measure(void); // measure the temparature
+void output_clip(void); // clip indicator
+void indi_flash (void); // universal indicator flash
+void temp_trip (void); // action to be taken when overtemp
+void acdetect(void); // triggers the counter
/************************************ analog_input *********************************/
+void trip(void) {
-void analog_input (void) {
-
- templ = left_temp*3.3;
- tempr = right_temp*3.3;
-
- //if ((templ > TRIPOFF) || (tempr > TRIPOFF)) {
- // temp_status = BAD; } else (temp_status = OK);
-
- if ((templ > TEMPHIGH) || (tempr > TEMPHIGH)) {
- clip = HIGH;}
- else (clip = LOW);
+
+ // temp alarm on either input
+ if ((t_left >= TEMPHIGH) || (t_right >= TEMPHIGH)) {
+ clip = HIGH; }
- if (((templ > TRIPON) || (tempr > TRIPON))) { // && ((templ > TRIPOFF) || (tempr > TRIPOFF)) && (FLAG1 == TRUE)) {
- SPKR = LOW;
- indi_flash();
- }
-
- if ((templ <= TRIPOFF) && (tempr <= TRIPOFF) && (FLAG1 == TRUE)){
- SPKR = HIGH;}
- }
-
+ if ((t_left < TEMPHIGH) && (t_right < TEMPHIGH) && (FLAG1 == TRUE)) {
+ SPKR = HIGH; }
+
+ if ((t_left > TRIPON) || (t_right > TRIPON)) { //temp trip
+ SPKR = LOW;
+ F1 = TRUE; }
+
+ // below is to turn speaker relay back ON if the temperature has fallen BELOW TRIPOFF
+
+ if (((t_left < TRIPOFF) && (t_right < TRIPOFF)) && (FLAG1 == TRUE)){
+ SPKR = HIGH;
+ clip = LOW;
+ F1 = FALSE; }
+
+
+ }
/*********************************** ACDET1 Interrupt ******************************/
void acdetect(void)
{
- ACDET1.rise(NULL);
+ ACDET1.rise(NULL); // prevent accidental re-entry
+
if (mains_cnt < amp_settle) {
mains_cnt++;
- FLAG1 = FALSE;
+ FLAG1 = FALSE; // FLAG1 only becomes TRUE after power up process is complete
}
else if (mains_cnt >= amp_settle) {
- FLAG1 = TRUE; // fully powered up at this point
- mains_cnt = amp_settle;
- } // after power up mains_cnt is held to amp_settle
- ACDET1.rise(&acdetect);
+ FLAG1 = TRUE; // fully powered up at this point
+ mains_cnt = amp_settle; // after power up mains_cnt is held to amp_settle
+ }
+
+ ACDET1.rise(&acdetect); // reinstate the interrupt
}
/******************************** output clip ****************************************/
void output_clip(void) {
- clip_cnt = CLIP_ON;
-
- }
+ clip_cnt = CLIP_ON; }
-/********************** power down routine for Trigger input *************************/
-void power_down(void)
-{
- __disable_irq();
- SPKR = LOW;
- INDI = HIGH;
- wait_ms(2);
- INRUSH = LOW;
- if (FLAG_TRIGGER == TRUE) {
- FLAG_TRIGGER = FALSE;
- PWR_R = LOW;
- }
- FLAG1 = FALSE;
- do {
- continue;
- } while(1); // just wait here unit all power is gone
- // amplifier is in power down mode
-}
-
/******************************** indi_flash ***************************************/
+// this just flashes the power LED to indicate amp is in power-up cycle
+// or a temperature shutdown
void indi_flash(void)
{
@@ -129,72 +125,106 @@
indi_flip = 0;
}
}
+/************************************ temp_measure **********************************/
+/* This routine fetches the NTC resistance as measured at the A-D inputs left_temp */
+/* and right Temp. It uses the Steinhart-Hart NTC R>T equation to compute the */
+/* temperature.left_temp and right_temp are A-D inputs defined in the pindef.h file */
-/************************************ main() ***************************************/
+void temp_measure(void) {
+
+float vo_left;
+float vo_right;
+float r_left;
+float r_right;
+float l_roh;
+float r_roh;
+
+// first, fetch the NTC resistances
+
+ vo_left = left_temp*Vref; //scale the A-D reading for Vref = 3.3V
+ vo_right = right_temp*Vref;
+
+ r_left = vo_left/((Vref-vo_left)/Ref);
+ r_right = vo_right/((Vref-vo_right)/Ref);
+
+// from the NTC resistance, calculate the temperature in Kelvin using the
+// simplified Steinhart-Hart Equation.
+
+ l_roh = Ro*(pow(e,(-B/To)));
+ t_left = (B/(log(r_left/l_roh)))-(273+cal65);
+
+ r_roh = Ro*(pow(e,(-B/To)));
+ t_right = (B/(log(r_right/r_roh)))-(273+cal65);
+
+ //printf used for temp debugging. Clock must be slowed to ~ 1Hz
+ //printf("t_left = %f t_right = %f \n\r", t_left, t_right);
+
+ }
+
+
+/************************************* main() ***************************************/
int main(void)
{
- __disable_irq(); // just to make sure we can set up correctly without problems
- INRUSH = LOW; // power bypass disabled
- SPKR = LOW; // speakers muted
- PWR_R = LOW; // power ON/OFF relay is OFF
- INDI = HIGH; // open drain indicator output is deactivated - take LOW
- clip = LOW;
- clip_in.mode(PullUp); // clip input
+ __disable_irq(); // just to make sure we can set up correctly without problems
+ INRUSH = LOW; // power bypass disabled
+ SPKR = LOW; // speakers muted
+ PWR_R = LOW; // power ON/OFF relay is OFF - only used if TRIGGER is used
+ INDI = HIGH; // open drain indicator output is deactivated - active LOW
+ clip = LOW; // clip LED driver output
+ clip_in.mode(PullUp); // clip input
clip_in.fall(&output_clip);
clip_cnt = 0;
+ ERROR.mode(PullUp);
+ PWR_D.mode(PullDown); // used to detect power down
ACDET1.mode(PullDown);
- ACDET1.rise(&acdetect); // trigger counter on rising edge
+ ACDET1.rise(&acdetect); // trigger counter on rising edge
+ SYNC = LOW; // SYNC flips once every mains cycle - 20ms period @ 50 Hz
+
+ FLAG1 = FALSE; // force a fault condition until first pass through main loop
+ F1 = TRUE; // assume we are over temperature until our first sensor reading
+ INDI = HIGH; // power LED is ON steady
+ __enable_irq();
- SYNC = LOW;
- wait_ms(500); // let PSU etc settle in first ~1 mains cycles
-
-// if (PWR_D == HIGH) { // power came in via TRIGGER input
-// FLAG_TRIGGER = TRUE;
-// PWR_R = HIGH; // turn the main power relay ON - only used
-// } // with amplifiers with TRIGGER input facility
- INDI = HIGH; // power LED is ON
- __enable_irq();
- Watchdog wdt; // enable the WDT just before we start the main loop
- wdt.kick(AC_LOSS);
+ Watchdog wdt; // enable the WDT just before we start the main loop
+ wdt.kick(AC_LOSS); // kick the WDT at regular 25 ms intervals (set by AC_LOSS)
-LOOP: // this main loop is driven by the 20ms/16.6ms interrupts
- // generated by the ACDET1 input
- // if the INT's fail to arrive after 25ms, the AC power
- // is lost and the WDT will reset the system = power down
- __WFI(); // waiting for ACDET1 INT
- wait_ms(5); // make sure we are away from the zero crossing 50 Hz or 60 Hz
- wdt.kick();
- acdetect();
-
- if (PWR_D == HIGH) { // check if input power detector is HIGH
- FLAG_TRIGGER = TRUE;
- PWR_R = HIGH; } // turn on main power relay
-
- if ((ERROR == LOW) && (FLAG1 == TRUE)) { // we have a fault condition but will
- SPKR = LOW; // skip this if the error clears itself
+LOOP: // this main loop is driven by the 20ms/16.6ms interrupts
+ // generated by the ACDET1 input
+ // if the INT's fail to arrive after 25ms, the AC power
+ // is assumed lost and the WDT will reset the system = power down
+ // de-engergizing all relays
+ __WFI(); // waiting for ACDET1 INT
+ wait_ms(1); // make sure we are away from the zero crossing 50 Hz or 60 Hz
+ wdt.kick();
+
+ if ((mains_cnt >= amp_settle) && (ERROR == HIGH) && (FLAG1 == FALSE)) {
+ INDI = HIGH;
+ SPKR = HIGH; } // inrush and amp settle complete - enable SPKR if no ERROR
+
+ if (mains_cnt > inrush_t) {
+ INRUSH = HIGH;}
+
+ // make sure the clip LED goes OFF if all is ok
+ if((clip_cnt <= 0) && (SPKR == HIGH) && (ERROR == HIGH)) {
+ INDI = HIGH; }
+
+ if (clip_cnt <= 0) { // note: clip flashes on change of state
+ clip = LOW;} // i.e on edges
+ else if (clip_cnt > 0) {
+ clip = HIGH;
+ INDI = LOW; } // so LED is RED on clip and not ORANGE
+
+ if ((ERROR == LOW) || (FLAG1 == FALSE)) {
+ SPKR = LOW;
+ indi_flash(); }
+
+ temp_measure();
+ trip();
+
+ if (F1 == TRUE) {
indi_flash(); }
-
- if ((ERROR == HIGH) && (FLAG1 == TRUE)){
- INDI = HIGH; }
-
- if(mains_cnt < amp_settle) {
- INRUSH = HIGH;
- indi_flash(); }
-
- if ((mains_cnt >= inrush_t) && (mains_cnt >= amp_settle) == TRUE) {
- SPKR = HIGH; }
-
- if ((PWR_D == LOW) && (FLAG_TRIGGER == TRUE)) {
- power_down(); }
-
- if (clip_cnt <= 0) {
- clip = LOW;}
- else if (clip_cnt != 0) {
- clip = HIGH;}
- analog_input();
-
- SYNC = !SYNC; // ACDET1 sync output for debugging
+ SYNC = !SYNC; // ACDET1 sync output for debugging
indi_flip++;
clip_cnt--;
goto LOOP;