arm/avr/chaos: hv_safe()

- WDT timeout at 1s
- toggle LED in WDT interrupt
- enable WDT reset
- keep WDT interrupting, reset only when stuck `cli()`
- `hv_safe()` when WDT interrupts accumulate
- `hv_safe()` shuts down hvosc, dac and optionally portc.  
- `hv_is_safe()` when hvosc is off and dac is off.


git-svn-id: svn+ssh://asterix.ieap.uni-kiel.de/home/subversion/stephan/solo/eda/arm/avr@8952 bc5caf13-1734-44f8-af43-603852e9ee25

Makefile

@@ -16,7 +16,8 @@ CC=avr-gcc -Wall -MMD -std=c99 -O3 -mmcu=$(MCU) \
   -funsigned-char \
   -funsigned-bitfields \
   -fpack-struct \
-  -fshort-enums
+  -fshort-enums \
+  -fverbose-asm
 
 CFLAGS = $($*_CFLAGS) $(DEBUG)
 

chaos/chaos.c

@@ -66,7 +66,7 @@ static inline void avrdac_set(unsigned int d)
 }
 
 #include <avr/wdt.h>
-unsigned char wdt_init(unsigned char mode);
+void wdt_init(unsigned char mode);
 unsigned char wdt_count;
 unsigned char wdt_saved;
 
@@ -74,8 +74,7 @@ enum {
 	WDT_MODE_LIVE = 2, // = any command kick
 	WDT_MODE_KICK = 3, // only 'W' command kicks
 	WDT_MODE_HV   = 4, // ≥ 'H' command kicks
-	WDT_MODE_FULL = 5, // ≥ do not allow HV reset to be interrupted
+	WDT_MODE_RAMP = 5, // ≥ dac_ramp kicks
-	WDT_MODE_RAMP = 6, // ≥ dac_ramp kicks
 };
 
 static inline void wdt_kick()
@@ -89,7 +88,6 @@ struct {
 	unsigned int dac_nominal;
 	unsigned int dac_off;
 	unsigned int tick_period;
-	unsigned int wdt_tick_period;
 	unsigned char flags;
 	unsigned char flags2;
 	unsigned char wdt_timeout;
@@ -111,14 +109,11 @@ struct {
 	unsigned char hvosc_dc;
 	unsigned char padding[2];
 } conf = {
-	.wdt_timeout     = 10,    // 2 min
+	.wdt_timeout     = 120,   // 2 min
-	.wdt_tick_period = TICK_NS(100000L),   // 100µs
 	.tick_period     = TICK_NS(10000000L), //  10ms
 	.avradc          = 0x7f,  // off
 	.adcconf         = 0x8500,// RST
 	.ddrc            = 2,     // OC1B HVOSC
-	.hvosc_freq      = 51,
-	.hvosc_dc        = 9,
 };
 
 enum {
@@ -164,10 +159,26 @@ void conf_init()
 	}
 }
 
-static inline void led_hv()
+int hv_is_safe()
+{
+	return !hvosc_is_on() && conf.dac==conf.dac_off;
+}
+
+void hv_safe()
+{
+	hvosc_init(0, 0);
+	if (conf.flags2 & FLAG2_PC_HV)
+		PORTC = conf.portc_off;
+	unsigned char sreg = disable_irq();
+	ltc1655_cmd(INT2FRAME(conf.dac_off));
+	conf.dac = conf.dac_off;
+	enable_irq(sreg);
+}
+
+void toggle_hv_led()
 {
 	if (conf.flags2 & FLAG2_HVLED) {
-		if (conf.dac == conf.dac_off)
+		if (hv_is_safe())
 			led_toggle(LED_GREEN);
 		else
 			led_toggle(LED_RED);
@@ -200,8 +211,8 @@ int main()
 		const char *p;
 		spi_slave_Rx(cmd, 3);
 		resp[0] = cmd[0];
+		toggle_hv_led();
 		sreg = disable_irq();
-		led_hv();
 		if (conf.wdt_mode == WDT_MODE_LIVE)
 			wdt_kick();
 		switch (cmd[0]) {
@@ -254,13 +265,12 @@ int main()
 			hvosc_init(conf.hvosc_freq, conf.hvosc_dc);
 			break;
 		case 'I':
-			int2frame(tick_freq(), resp+1);
-			conf.tick_period = frame2int(cmd+1);
-			tick_init(conf.tick_period);
-			break;
 		case 'i':
-			int2frame(conf.wdt_tick_period, resp+1);
+			int2frame(tick_freq(), resp+1);
-			conf.wdt_tick_period = frame2int(cmd+1);
+			if (upcase(cmd[0])) {
+				conf.tick_period = frame2int(cmd+1);
+				tick_init(conf.tick_period);
+			}
 			break;
 		case 'A':
 			ads8688_cmd(cmd+1, resp+1);
@@ -311,10 +321,12 @@ int main()
 			resp[2] = conf.wdt_timeout;
 			if (cmd[2])
 				conf.wdt_timeout = cmd[2];
-			if (cmd[1])
+			if (cmd[1]) {
-				sreg = wdt_init(cmd[1]);
+				wdt_init(cmd[1]);
+				sreg = (1<<SREG_I);
+			}
 			else {
-				int2frame(wdt_count, resp+1);
+				resp[2] = wdt_count;
 				wdt_kick();
 			}
 			break;
@@ -515,45 +527,34 @@ void dac_ramp(unsigned int target)
 
 ISR(WDT_vect)
 {
+	toggle_hv_led();
 	if (wdt_count++ < conf.wdt_timeout)
-		return;
+		goto wdt_out;
-	tick_init(conf.wdt_tick_period);
+	hv_safe();
-	unsigned char mode = conf.wdt_mode;
-	conf.wdt_mode = WDT_MODE_RAMP;
-	do 
-		dac_ramp(conf.dac_off);
-	while (mode >= WDT_MODE_FULL && conf.dac != conf.dac_off);
 	wdt_reset();
-	if (conf.dac == conf.dac_off) {
-		if (conf.flags2 & FLAG2_PC_HV)
-			PORTC = conf.portc_off;
-		if (conf.flags2 & FLAG2_HVOSC)
-			hvosc_init(0, 0);
-	}
-	tick_init(conf.tick_period);
 	if (conf.wdt_save_addr && !wdt_saved) {
 		wdt_saved = 1;
 		eeprom_save(conf.wdt_save_addr);
 	}
-	WDTCSR |= WDIF; // should not be necessary 
+wdt_out:
+	WDTCSR |= WDIE;
 }
 
-unsigned char wdt_init(unsigned char mode)
+void wdt_init(unsigned char mode)
 {
 	conf.wdt_mode = mode;
 	wdt_reset();
 	if (mode < WDT_MODE_LIVE) {
 		WDTCSR = 0;
-		return 0;
+		return;
 	}
-	// 8s timeout, WDT interrupt enabled
+	// 1s timeout, WDT interrupt enabled
 	__asm__("STS %[CSR], %[CE]"     "\n\t"
 		"STS %[CSR], %[IE]"     "\n"
 		::[CSR] "n" (&WDTCSR),
-		 [CE] "r" ((unsigned char)(1<<WDCE | 1<<WDE | 1<<WDP3 | 1<<WDP0)),
+		 [CE] "r" ((unsigned char)(1<<WDCE | 1<<WDE | 1<<WDP2 | 1<<WDP1)),
-		 [IE] "r" ((unsigned char)(1<<WDIE          | 1<<WDP3 | 1<<WDP0))
+		 [IE] "r" ((unsigned char)(1<<WDIE | 1<<WDE | 1<<WDP2 | 1<<WDP1))
 		);
-	return 1 << SREG_I;
 }
 
 void eeprom_save(unsigned char a)

chaos/hvosc.h

@@ -18,3 +18,9 @@ static inline void hvosc_init(unsigned char freq, unsigned char dc)
 	OCR1BH = 0;
 	OCR1BL = freq-dc;
 }
+
+static inline
+int hvosc_is_on()
+{
+	return TCCR1A;
+}