DS18B20 Temperature sensor support

This is currently a failed hack, but I wanted to keep the code anyway because I may be able to salvage it in the future. So I'm creating a separate branch named temperature to store this work. The DS18B20 is installed by connecting the GND, DQ, and Vdd pins to the ATmega's GND, PC2, and PC5 pins with a 4.7k pull-up between PC2 and PC5. I drilled a small hole in the base of the case and inserted the head of the DS18B20 through the hole to get ambient temperature. This commit displays temperature (in Fahrenheit) along with the date. I consider this a failed hack because the Ice Tube Clock generates heat, and the clock itself and surrounding areas has a temperature that is 1-8 degrees Fahrenheit higher than ambient temperature. So, the temperature reading is seldom accurate. :-( This commit does include code that is a good example of how to query the DS18B20 via the 1-Wire protocol.
johngarchie · Feb 11, 2013 · 32e1425 · 32e1425
1 parent 5e05f00
commit 32e1425
Show file tree

Hide file tree

Showing 12 changed files with 351 additions and 36 deletions.
diff --git a/Makefile b/Makefile
@@ -13,7 +13,7 @@ PROJECT ?= icetube
 
 # object files
 OBJECTS ?= icetube.o system.o time.o alarm.o pizo.o \
-	   display.o buttons.o mode.o usart.o gps.o
+	   display.o buttons.o mode.o usart.o gps.o temp.o
 
 # avr microcontroller processing unit
 AVRMCU ?= atmega328p

diff --git a/config.h b/config.h
@@ -14,7 +14,7 @@
 // "next selected option," or "increment selected number."
 //
 //
-#define ADAFRUIT_BUTTONS
+// #define ADAFRUIT_BUTTONS
 
 
 // AUTOMATIC DIMMER HACK
@@ -27,7 +27,7 @@
 //   http://forums.adafruit.com/viewtopic.php?f=41&t=12932
 //
 //
-// #define AUTOMATIC_DIMMER
+#define AUTOMATIC_DIMMER
 
 
 // GPS TIMEKEEPING
@@ -53,7 +53,7 @@
 //   http://forums.adafruit.com/viewtopic.php?f=41&t=14941
 //
 //
-// #define EXTERNAL_CLOCK
+#define EXTERNAL_CLOCK
 
 
 // EXTENDED BATTERY HACK
@@ -71,7 +71,17 @@
 //   http://forums.adafruit.com/viewtopic.php?f=41&t=36697
 //
 //
-// #define PICO_POWER
+#define PICO_POWER
+
+
+// TEMPERATURE SENSOR HACK
+//
+// With a DS18B20 digial sensor probe attached to PC2, the clock can display
+// temperature readings.
+//
+//
+#define TEMPERATURE_SENSOR
+#define TEMPERATURE_ADJUST -96
 
 
 // DISPLAY BRIGHTNESS / BOOST CONFIGURATION
@@ -106,7 +116,7 @@
 // macros defined in usart.h.  The default speed is 9600 baud.
 //
 //
-// #define DEBUG
+#define DEBUG
 
 
 // USART BAUD RATE

diff --git a/display.c b/display.c
@@ -3,7 +3,6 @@
 //
 //    PB5 (SCK)                      MAX6921 CLK pin
 //    PB3 (MOSI)                     MAX6921 DIN pin
-//    PC5                            photoresistor pull-up
 //    PC4 (ADC4)                     photoresistor voltage
 //    PC3                            MAX6921 BLANK pin
 //    PC0                            MAX6921 LOAD pin
@@ -63,6 +62,7 @@ uint8_t ee_display_digit_times[] EEMEM = {15, 15, 15, 15, 15, 15, 15, 15, 15};
 #define DISPLAY_DOT      SEG_H
 #define DISPLAY_DASH     SEG_G
 #define DISPLAY_SLASH    SEG_B | SEG_G | SEG_E
+#define DISPLAY_DEGREE   SEG_A | SEG_B | SEG_F | SEG_G;
 #define DISPLAY_WILDCARD SEG_A | SEG_G | SEG_D
 
 // codes for vfd letter display
@@ -154,12 +154,12 @@ void display_init(void) {
     // as inputs *without* pull-ups!?!?)
     DDRB  &= ~_BV(PB5) & ~_BV(PB3);  // set to input
 
-    // configure photoresistor pull-up pin
-    DDRC  |=  _BV(PC5);  // set pin as output
-    PORTC &= ~_BV(PC5);  // pull to ground
-
+#ifdef AUTOMATIC_DIMMER
     // disable digital circuitry on photoresistor pins
     DIDR0 |= _BV(ADC5D) | _BV(ADC4D);
+#else
+    PORTC |= _BV(PC4);  // enable pull-up on unused pin
+#endif  // AUTOMATIC_DIMMER
 
     // set initial photo_avg to maximum ambient light
     display.photo_avg = UINT16_MAX;
@@ -187,10 +187,7 @@ uint8_t display_onbutton(void) {
 
 // enable display after low-power mode
 void display_wake(void) {
-    // enable external and internal photoresistor pull-ups (the latter
-    // ensures a defined value if no photoresistor installed)
-    PORTC |= _BV(PC5) | _BV(PC4);  // output +5v, enable pull-up
-
+#ifdef AUTOMATIC_DIMMER
     // enable analog to digital converter
     power_adc_enable();
 
@@ -203,6 +200,7 @@ void display_wake(void) {
     // ADSC    =   1:  start ADC conversion now
     // ADPS2:0 = 110:  system clock / 64  (8 MHz / 4 = 125 kHz)
     ADCSRA = _BV(ADEN) | _BV(ADSC) | _BV(ADPS2) | _BV(ADPS1);
+#endif  // AUTOMATIC_DIMMER
 
     // configure spi sck and mosi pins as outputs
     DDRB |= _BV(PB5) | _BV(PB3);
@@ -230,12 +228,11 @@ void display_sleep(void) {
     PORTD &= ~_BV(PD6); // boost fet off (pull low)
     PORTD |=  _BV(PD3); // MAX6921 power off (pull high)
 
-    // disable external and internal photoresistor pull-ups
-    PORTC &= ~_BV(PC5) & ~_BV(PC4);  // pull to ground, disable pull-up
-
+#ifdef AUTOMATIC_DIMMER
     // disable analog to digital converter
     ADCSRA = 0;  // disable ADC before power_adc_disable()
     power_adc_disable();
+#endif  // AUTOMATIC_DIMMER
 
     // configure MAX6921 LOAD and BLANK pins
     PORTC &= ~_BV(PC0) & ~_BV(PC3); // clamp to ground
@@ -661,6 +658,9 @@ void display_char(uint8_t idx, char c) {
 	    case '/':
 		display.prebuf[idx] = DISPLAY_SLASH;
 		break;
+	    case '\370':
+		display.prebuf[idx] = DISPLAY_DEGREE;
+		break;
 	    default:
 		display.prebuf[idx] = DISPLAY_WILDCARD;
 		break;

diff --git a/gps.c b/gps.c
@@ -1,7 +1,5 @@
 // gps.c  --  parses gps output from usart and sets time accordingly
 //
-//    PB4    gps power control; high normally, pulled low during sleep
-//
 
 
 #include "config.h"
@@ -47,10 +45,6 @@ uint8_t ee_gps_rel_utc_minute EEMEM = 0;
 // load time offsets from gmt/utc
 void gps_init(void) {
     gps_loadrelutc();
-
-    // configure gps power pin (gps off)
-    PORTB &= ~_BV(PB4);  // clamp to ground
-    DDRB  |=  _BV(PB4);  // set to ouput
 }
 
 
@@ -59,9 +53,6 @@ void gps_wake(void) {
     // enable usart rx interrupt
     UCSR0B |= _BV(RXCIE0);
 
-    // configure gps power pin (gps on)
-    PORTB |= _BV(PB4);  // clamp to +5v
-
     // give gps time to acquire signal before issuing "gps lost" warning
     gps.warn_timer = GPS_WARN_TIMEOUT;
 }
@@ -71,9 +62,6 @@ void gps_wake(void) {
 void gps_sleep(void) {
     // disable usart rx interrupt
     UCSR0B &= ~_BV(RXCIE0);
-
-    // configure gps power pin (gps off)
-    PORTB &= ~_BV(PB4);  // clamp to ground
 }
 
 

diff --git a/icetube.c b/icetube.c
@@ -34,6 +34,7 @@
 #include "mode.h"
 #include "usart.h"
 #include "gps.h"
+#include "temp.h"
 
 
 // define ATmega328p lock bits
@@ -87,6 +88,9 @@ int main(void) {
 #ifdef GPS_TIMEKEEPING
     gps_init();
 #endif  // GPS_TIMEKEEPING
+#ifdef TEMPERATURE_SENSOR
+    temp_init();
+#endif  // TEMPERATURE_SENSOR
 
     // if the system is on battery power, sleep until power restored
     if(system_power() == SYSTEM_BATTERY) {
@@ -99,6 +103,7 @@ int main(void) {
     sei(); // enable interrupts
 
     // wakey, wakey
+    system_wake();
 #if defined(DEBUG) || defined(GPS_TIMEKEEPING)
     usart_wake();
 #endif  // DEBUG || GPS_TIMEKEEPING
@@ -111,6 +116,9 @@ int main(void) {
 #ifdef GPS_TIMEKEEPING
     gps_wake();
 #endif  // GPS_TIMEKEEPING
+#ifdef TEMPERATURE_SENSOR
+    temp_wake();
+#endif  // TEMPERATURE_SENSOR
 
     // half-second beep on system reset
     pizo_setvolume(3, 0);
@@ -129,11 +137,13 @@ ISR(TIMER2_COMPA_vect) {
     sei();  // allow nested interrupts
 
     if(system.status & SYSTEM_SLEEP) {
+	system_semitick();
 	time_tick();
 	alarm_tick();
 	pizo_tick();
 	wdt_reset();
     } else {
+	system_semitick();
 	time_tick();
 	buttons_tick();
 	alarm_tick();
@@ -143,6 +153,9 @@ ISR(TIMER2_COMPA_vect) {
 #ifdef GPS_TIMEKEEPING
 	gps_tick();
 #endif  // GPS_TIMEKEEPING
+#ifdef TEMPERATURE_SENSOR
+	temp_tick();
+#endif  // TEMPERATURE_SENSOR
 	if(semitick_successful) wdt_reset();
 	semitick_successful = 0;
     }
@@ -167,6 +180,7 @@ ISR(TIMER0_OVF_vect) {
 
 	// code below runs every "semisecond" or
 	// every 0.99 microseconds (1.01 khz)
+	system_semitick();
 	time_semitick();
 	buttons_semitick();
 	alarm_semitick();
@@ -176,6 +190,9 @@ ISR(TIMER0_OVF_vect) {
 #ifdef GPS_TIMEKEEPING
 	gps_semitick();
 #endif  // GPS_TIMEKEEPING
+#ifdef TEMPERATURE_SENSOR
+	temp_semitick();
+#endif  // TEMPERATURE_SENSOR
 
 	semitick_successful = 1;
     }
@@ -199,12 +216,16 @@ ISR(ANALOG_COMP_vect) {
     buttons_sleep();  // disable button pull-up resistors
     time_sleep();     // save current time
     mode_sleep();     // does nothing
+#ifdef TEMPERATURE_SENSOR
+    temp_sleep();
+#endif  // TEMPERATURE_SENSOR
 #ifdef GPS_TIMEKEEPING
     gps_sleep();      // disable usart rx interrupt
 #endif  // GPS_TIMEKEEPING
 #if defined(DEBUG) || defined(GPS_TIMEKEEPING)
     usart_sleep();    // disable usart
 #endif  // DEBUG || GPS_TIMEKEEPING
+    system_sleep();   // pulls PC5 low, if necessary
     pizo_sleep();     // adjust buzzer for slower clock
 
     // the bod settings allow the clock to run a battery down to 1.7 - 2.0v.
@@ -220,6 +241,7 @@ ISR(ANALOG_COMP_vect) {
     sei();  // allow interrupts
 
     pizo_wake();     // adjust buzzer for faster clock
+    system_wake();   // pulls PC5 high, if necessary
     mode_wake();     // display time after waking
     buttons_wake();  // enable button pull-ups
     alarm_wake();    // enable alarm switch pull-up
@@ -229,5 +251,8 @@ ISR(ANALOG_COMP_vect) {
 #ifdef GPS_TIMEKEEPING
     gps_wake();      // enable usart rx interrupt
 #endif  // GPS_TIMEKEEPING
+#ifdef TEMPERATURE_SENSOR
+    temp_wake();
+#endif  // TEMPERATURE_SENSOR
     display_wake();  // start boost timer and enable display
 }
diff --git a/mode.c b/mode.c
@@ -18,6 +18,7 @@
 #include "buttons.h"  // for processing button presses
 #include "gps.h"      // for setting the utc offset
 #include "usart.h"    // for debugging output
+#include "temp.h"     // for displaying current temperature
 
 
 // extern'ed clock mode data
@@ -116,11 +117,16 @@ void mode_semitick(void) {
 		if(time.dateformat & TIME_DATEFORMAT_SHOWYEAR) {
 		    mode_update(MODE_YEAR_DISPLAY, DISPLAY_TRANS_LEFT);
 		} else {
-		    mode_update(MODE_TIME_DISPLAY, DISPLAY_TRANS_UP);
+		    mode_update(MODE_TEMP_DISPLAY, DISPLAY_TRANS_LEFT);
 		}
 	    }
 	    return;  // time ourselves; skip code below
 	case MODE_YEAR_DISPLAY:
+	    if(btn || ++mode.timer > 1250) {
+		mode_update(MODE_TEMP_DISPLAY, DISPLAY_TRANS_LEFT);
+	    }
+	    return;  // time ourselves; skip code below
+	case MODE_TEMP_DISPLAY:
 	    if(btn || ++mode.timer > 1250) {
 		mode_update(MODE_TIME_DISPLAY, DISPLAY_TRANS_UP);
 	    }
@@ -1447,6 +1453,12 @@ void mode_update(uint8_t new_state, uint8_t disp_trans) {
 	    display_digit(5, time.year / 10);
 	    display_digit(6, time.year % 10);
 	    break;
+	case MODE_TEMP_DISPLAY:
+	    display_pstr(0, PSTR("  xx \370F"));
+	    int16_t degF = temp_degF();
+	    display_digit(3, degF / 10);
+	    display_digit(4, degF % 10);
+	    break;
 	case MODE_ALARMSET_DISPLAY:
 	    display_pstr(0, PSTR("alar set"));
 	    break;

diff --git a/mode.h b/mode.h
@@ -16,6 +16,7 @@ enum {
         MODE_DAYOFWEEK_DISPLAY,
         MODE_MONTHDAY_DISPLAY,
         MODE_YEAR_DISPLAY,
+        MODE_TEMP_DISPLAY,
         MODE_ALARMSET_DISPLAY,
         MODE_ALARMIDX_DISPLAY,
         MODE_ALARMTIME_DISPLAY,

diff --git a/system.c b/system.c
@@ -1,8 +1,9 @@
 // system.c  --  system functions (idle, sleep, interrupts)
 //
 //    PB4 (MISO)           unused pin
-//    PC2                  unused pin
-//    PC1                  power from voltage regulator
+//    PC5                  photoresistor pull-up / temperature sensor power
+//    PC2                  1-Wire bus for temperature sensor
+//    PC1                  unused pin or power from voltage regulator
 //    AIN1 (PD7)           divided system voltage
 //    analog comparator    detects low voltage (AIN1)
 //
@@ -37,12 +38,22 @@ void system_init(void) {
 
     // enable pull-up resistors on unused pins to ensure a defined value
     PORTB |= _BV(PB4);
-#ifdef PICO_POWER
-    PORTC |= _BV(PC2);
+
+#if defined(TEMPERATURE_SENSOR) || defined(AUTOMATIC_DIMMER)
+    DDRC  |=  _BV(PC5);  // set pin as output
+    PORTC &= ~_BV(PC5);  // pull to ground
 #else
-    PORTC |= _BV(PC2) | _BV(PC1);
+    PORTC |=  _BV(PC5);  // enable pull-up
+#endif  // TEMPERATURE_SENSOR || AUTOMATIC_DIMMER
+
+#ifndef PICO_POWER
+    PORTC |= _BV(PC2);
 #endif  // PICO_POWER
 
+#ifndef TEMPERATURE_SENSOR
+    PORTC |= _BV(PC1);
+#endif  // TEMPERATURE_SENSOR
+
     // use internal bandgap as reference for analog comparator
     // and enable analog comparator interrupt on falling edge
     // of AIN1 (interrupt triggers when adaptor power fails)
@@ -56,6 +67,21 @@ void system_init(void) {
     power_all_disable();
 }
 
+#if defined(TEMPERATURE_SENSOR) || defined(AUTOMATIC_DIMMER)
+// pull power indicator pin high when waking
+void system_wake(void) {
+    PORTC |= _BV(PC5);
+}
+#endif  // TEMPERATURE_SENSOR || AUTOMATIC_DIMMER
+
+
+#if defined(TEMPERATURE_SENSOR) || defined(AUTOMATIC_DIMMER)
+// place managed pins in low power state
+void system_sleep(void) {
+    PORTC &= ~_BV(PC5);  // pull low when sleeping
+}
+#endif  // TEMPERATURE_SENSOR || AUTOMATIC_DIMMER
+
 
 // repeatedly enter idle mode forevermore
 void system_idle_loop(void) {