measure ADC every 1ms at timer code, compute averaged ADC value when used

ChangeLog

@@ -3,6 +3,7 @@
     minimum battery voltage set to 2V for those experimenting with 1S cell
     PPM length shortened to "NUM_CHANNELS x 2ms + 5ms" to send new data
 	to receiver as soon as possible
+    ADC measuring every 1ms, averaging last 4 samples when used
 
 *0.4.1 (17 Aug 2011)
 

README.internal

@@ -23,12 +23,14 @@ ppm_interrupt
     - wakeups task CALC during SYNC signal
 timer_interrupt
     - timer2 overflow
+    - every 1ms read ADC values
     - every 5ms
-    - increments time from start
-    - count LCD blink time and wakeups task LCD
-    - handles buzzer
-    - wakeups task INPUT
-    - handles task MENU delay and wakeups this task
+	- increments time from start
+	- count LCD blink time and wakeups task LCD
+	- handles buzzer
+	- wakeups task INPUT
+	- wakeups task MENU when it wants ADC values (calibrate, ...)
+	- handles task MENU delay and wakeups this task
 
 
 
@@ -40,7 +42,7 @@ LCD
     - is waked up by lcd_update(), lcd_clear()
     - is waked up from timer to do automatic blinking
 INPUT
-    - is doing reading of ADC values and key matrix
+    - is doing reading key matrix and some ADC checks
     - is waked up from timer every 5ms
 CALC
     - is computing values for each servo and sync signal
@@ -48,10 +50,9 @@ CALC
     - also needed to wakeup after changing number of PPM channels in MENU
 MENU
     - is main program handling keys, menus, lcd
-    - is waked up from timer when menu_delay expired
+    - is waked up from timer when menu_delay expired or when ADC values needed
     - is waked up from INPUT task when
 	- buttons state changed
-	- MENU task wanted ADC values (for calibrate) or battery voltage
 	- status of battery low changed
 
 

TODO

 
-ADC wakeups - only every 1/2s instead of checking time at menu code
-ADC - measure every 1ms - timer 1ms, buttons code still every 5ms
 CALC - calc at end of SYNC signal
 	- measure durations of CALC
 	- at end of CALC PPM pulse and servo pulses

input.c

@@ -118,7 +118,7 @@ u16 buttons;
 u16 buttons_long;  // >1s press
 // variables for ADC values
 @near u16 adc_all_last[3], adc_battery_last;
-@near u16 adc_all_ovs[3], adc_battery;
+@near u16 adc_battery;
 @near u32 adc_battery_filt;
 
 
@@ -305,43 +305,26 @@ static void read_keys(void) {
 
 // ADC buffers, last 4 values for each channel
 #define ADC_BUFFERS  4
-@near static u16 adc_buffer[ADC_BUFFERS][3];
-static u8  adc_buffer_pos;
-
-
-// define missing ADC buffer registers
-volatile u16 ADC_DB0R @0x53e0;
-volatile u16 ADC_DB1R @0x53e2;
-volatile u16 ADC_DB2R @0x53e4;
-volatile u16 ADC_DB3R @0x53e6;
-
-// read ADC values and compute sum of last 4 for each channel
-#define ADC_NEWVAL(id) \
-    adc_all_last[id] = ADC_DB ## id ## R; \
-    buf[id] = adc_all_last[id]; \
-    adc_all_ovs[id] = adc_buffer[0][id] + adc_buffer[1][id] \
-                      + adc_buffer[2][id] + adc_buffer[3][id];
-static void read_ADC(void) {
-    u16 *buf = adc_buffer[adc_buffer_pos];
-    u8  dead;
+@near u16 adc_buffer0[ADC_BUFFERS];
+@near u16 adc_buffer1[ADC_BUFFERS];
+@near u16 adc_buffer2[ADC_BUFFERS];
+u16 adc_buffer_pos;
 
-    ADC_NEWVAL(0);
-    ADC_NEWVAL(1);
-    ADC_NEWVAL(2);
-    adc_battery_last = ADC_DB3R;
 
-    adc_buffer_pos++;
-    adc_buffer_pos &= 3;
+// read ADC values
+static void read_ADC(void) {
+    READ_ADC();
+}
 
-    BRES(ADC_CSR, 7);		// remove EOC flag
-    BSET(ADC_CR1, 0);		// start new conversion
 
-    // average battery voltage and check battery low
+// average battery voltage and check battery low
+static void update_battery(void) {
     // ignore very low, which means that it is supplied from SWIM connector
     adc_battery_filt = adc_battery_filt * (ADC_BAT_FILT - 1); // splitted - compiler hack
     adc_battery_filt = (adc_battery_filt + (ADC_BAT_FILT / 2)) / ADC_BAT_FILT
 		       + adc_battery_last;
     adc_battery = (u16)((adc_battery_filt + (ADC_BAT_FILT / 2)) / ADC_BAT_FILT);
+
     // start checking battery after 5s from power on
     if (time_sec >= 5) {
 	// wakeup task only when something changed
@@ -360,13 +343,12 @@ static void read_ADC(void) {
 	    }
 	}
     }
+}
 
-    // wakeup MENU task when showing battery or at calibrate
-    if (menu_wants_adc)
-	awake(MENU);
 
-    // reset inactivity timer when some steering or throttle applied
-    dead = cg.steering_dead_zone;
+// reset inactivity timer when some steering or throttle applied
+static void check_inactivity(void) {
+    u8 dead = cg.steering_dead_zone;
     if (dead < 20)  dead = 20;  // use some minimal dead zone for this check
     if (adc_steering_last < (cg.calib_steering_mid - dead) ||
         adc_steering_last > (cg.calib_steering_mid + dead))
@@ -388,9 +370,8 @@ static void read_ADC(void) {
 // input task, awaked every 5ms
 _Bool input_initialized;
 #define ADC_BUFINIT(id) \
-    adc_buffer[1][id] = adc_buffer[2][id] = adc_buffer[3][id] = \
-                        adc_buffer[0][id]; \
-    adc_all_ovs[id] = adc_buffer[0][id] << ADC_OVS_SHIFT;
+    adc_buffer ## id ## [1] = adc_buffer ## id ## [2] = \
+	adc_buffer ## id ## [3] = adc_buffer ## id ## [0];
 static void input_loop(void) {
 
     // read initial ADC values
@@ -410,10 +391,9 @@ static void input_loop(void) {
     input_initialized = 1;
 
     while (1) {
-	// read ADC only when EOC flag (only for first it will not be ready)
-	if (BCHK(ADC_CSR, 7))
-	    read_ADC();
 	read_keys();
+	check_inactivity();
+	update_battery();
 	stop();
     }
 }

input.h

@@ -64,23 +64,6 @@ extern volatile u16 buttons_long;	// >1s presses buttons
 #define btnl_all(mask)  ((buttons_long & (mask)) == (mask))
 
 
-// variables for ADC values
-extern @near volatile u16 adc_all_ovs[3];	// oversampled from 4 samples and is 4* more
-#define ADC_OVS_SHIFT 2
-#define ADC_OVS_ROUND 2
-#define adc_steering_ovs   adc_all_ovs[0]
-#define adc_throttle_ovs   adc_all_ovs[1]
-#define adc_ch3_ovs        adc_all_ovs[2]
-extern @near volatile u32 adc_battery_filt;	// battery will be filtered more times
-#define ADC_BAT_FILT  512
-extern @near volatile u16 adc_battery;	// adc_battery_filt >> ADC_BATTERY_SHIFT
-extern @near volatile u16 adc_all_last[3];	// last readed value
-#define adc_steering_last  adc_all_last[0]
-#define adc_throttle_last  adc_all_last[1]
-#define adc_ch3_last       adc_all_last[2]
-extern @near volatile u16 adc_battery_last;
-
-
 // reset pressed button(s)
 // do it after used that button in code
 extern void button_reset(u16 btn);
@@ -95,6 +78,65 @@ extern void button_autorepeat(u8 btn);
 
 
 
+
+
+// variables for ADC values
+
+// define missing ADC buffer registers
+volatile u16 ADC_DB0R @0x53e0;
+volatile u16 ADC_DB1R @0x53e2;
+volatile u16 ADC_DB2R @0x53e4;
+volatile u16 ADC_DB3R @0x53e6;
+
+// last readed values
+extern @near volatile u16 adc_all_last[3];
+#define adc_steering_last  adc_all_last[0]
+#define adc_throttle_last  adc_all_last[1]
+#define adc_ch3_last       adc_all_last[2]
+extern @near volatile u16 adc_battery_last;
+
+// ADC buffers, last 4 values for each channel
+//   average will be computed when used
+#define ADC_BUFFERS  4
+extern @near u16 adc_buffer0[ADC_BUFFERS];
+extern @near u16 adc_buffer1[ADC_BUFFERS];
+extern @near u16 adc_buffer2[ADC_BUFFERS];
+#define ADC_OVS_SHIFT 2
+#define ADC_OVS_ROUND 2
+#define adc_steering_ovs   (adc_buffer0[0] + adc_buffer0[1] + adc_buffer0[2] \
+			    + adc_buffer0[3])
+#define adc_throttle_ovs   (adc_buffer1[0] + adc_buffer1[1] + adc_buffer1[2] \
+			    + adc_buffer1[3])
+#define adc_ch3_ovs        (adc_buffer2[0] + adc_buffer2[1] + adc_buffer2[2] \
+			    + adc_buffer2[3])
+#define ADC_OVS(name) \
+    ((adc_ ## name ## _ovs + ADC_OVS_ROUND) >> ADC_OVS_SHIFT)
+
+// battery will be filtered more times
+extern @near volatile u32 adc_battery_filt;
+#define ADC_BAT_FILT  512
+extern @near volatile u16 adc_battery;	// adc_battery_filt / ADC_BAT_FILT
+
+// code reading last ADC values
+//   retypes to force more optimized code produced by compiler
+extern u16 adc_buffer_pos;	// step 2 (skip 16bit values)
+#define ADC_NEWVAL(id) \
+    *(u16 *)((u8 *)adc_buffer ## id ## + adc_buffer_pos) = \
+	adc_all_last[id] = \
+	ADC_DB ## id ## R;
+#define READ_ADC() \
+    ADC_NEWVAL(0); \
+    ADC_NEWVAL(1); \
+    ADC_NEWVAL(2); \
+    adc_battery_last = ADC_DB3R; \
+    *((u8 *)&adc_buffer_pos + 1) = (u8)((u8)((u8)adc_buffer_pos + 2) & 7); \
+    BRES(ADC_CSR, 7);		/* remove EOC flag */			   \
+    BSET(ADC_CR1, 0);		// start new conversion
+
+
+
+
+
 // INPUT task
 E_TASK(INPUT);
 extern _Bool input_initialized;

menu_service.c

@@ -88,7 +88,7 @@ void menu_calibrate(void) {
 	    // select actual voltage for channel 4
 	    if (channel == 1) {
 		key_beep();
-		val = (adc_steering_ovs + ADC_OVS_ROUND) >> ADC_OVS_SHIFT;
+		val = ADC_OVS(steering);
 		if (val < CALIB_ST_LOW_MID) {
 		    cg.calib_steering_left = val;
 		    seg = LS_MENU_MODEL;
@@ -106,7 +106,7 @@ void menu_calibrate(void) {
 	    }
 	    else if (channel == 2) {
 		key_beep();
-		val = (adc_throttle_ovs + ADC_OVS_ROUND) >> ADC_OVS_SHIFT;
+		val = ADC_OVS(throttle);
 		if (val < CALIB_TH_LOW_MID) {
 		    cg.calib_throttle_fwd = val;
 		    seg = LS_MENU_TRIM;
@@ -157,8 +157,22 @@ void menu_calibrate(void) {
 	}
 
 	// show ADC value if other than last val
-	if (channel == 4)  val = adc_battery;
-	else  val = (adc_all_ovs[channel-1] + ADC_OVS_ROUND) >> ADC_OVS_SHIFT;
+	switch (channel) {
+	    case 1:
+		val = ADC_OVS(steering);
+		break;
+	    case 2:
+		val = ADC_OVS(throttle);
+		break;
+	    case 3:
+		val = ADC_OVS(ch3);
+		break;
+	    case 4:
+		val = adc_battery;
+		break;
+	    default:		// to eliminate compiler warning
+		val = 0;
+	}
 	// only update display every 1s
 	if (time_sec >= update_time) {
 	    update_time = time_sec + 1;

timer.c

@@ -33,14 +33,15 @@ static @near u16 inactivity;
 
 // initialize timer 2 used to count seconds
 #define TIMER_5MS  (KHZ / 2 * 5)
+#define TIMER_1MS  (KHZ / 2)
 void timer_init(void) {
     BSET(CLK_PCKENR1, 5);	// enable clock to TIM2
     TIM2_CNTRH = 0;		// start at 0
     TIM2_CNTRL = 0;
     TIM2_PSCR = 1;		// clock / 2
     TIM2_IER = 0b00000001;	// enable update interrupt
-    TIM2_ARRH = hi8(TIMER_5MS - 1);	// count till 5ms time
-    TIM2_ARRL = lo8(TIMER_5MS - 1);
+    TIM2_ARRH = hi8(TIMER_1MS - 1);	// count till 1ms time
+    TIM2_ARRL = lo8(TIMER_1MS - 1);
     TIM2_CR1 = 0b00000101;	// URS-overflow, enable
 
     inactivity = cg.inactivity_alarm * 60;
@@ -50,13 +51,23 @@ void timer_init(void) {
 // count seconds from power on
 volatile u16 time_sec;
 volatile u8  time_5ms;
+volatile u8  time_1ms;
 static u16 menu_delay;		// timer for delay in MENU task
 
 
-// interrupt every 5ms
+// interrupt every 1ms
 @interrupt void timer_interrupt(void) {
     BRES(TIM2_SR1, 0);  // erase interrupt flag
 
+    // read ADC only when EOC flag (only for first it will not be ready)
+    if (input_initialized && BCHK(ADC_CSR, 7)) {
+	READ_ADC();
+    }
+
+    // increment 1ms steps
+    if (++time_1ms < 5)  return;
+    time_1ms = 0;
+
     // increment time from start
     if (++time_5ms >= 200) {
 
@@ -116,6 +127,10 @@ static u16 menu_delay;		// timer for delay in MENU task
     // wakeup INPUT task
     awake(INPUT);
 
+    // wakeup MENU task every 40ms when showing battery or at calibrate
+    if (menu_wants_adc && !(time_5ms & 0b00000111))
+	awake(MENU);
+
     // task MENU delay
     if (menu_delay && !--menu_delay)
 	awake(MENU);