Make Arduino timer stuff work on Contiki

New discovery: Contiki also uses timer 0. With almost the same interface
as Arduino. So we now completely get rid of wiring.c (only the main
file, the other wiring_xxx stay) and implement Arduino timer, delay, etc
in terms of the corresponding Contiki routines. Verified that now delay
works as expected. The LED in examples/osd/arduino-sketch blinks!

Before this, the arduino_init routine in wiring.c destroyed the timer-0
initialization of contiki, making both, contiki timer implementation
*and* contiki timer implementation fail if the arduino_init routine was
called. Now both work.

Squashed with following bug-fix commit.

apps/arduino/arduino-process.c

@@ -50,6 +50,8 @@
  */
 
 #include "arduino-process.h"
+#include "hw_timer.h"
+#include "hw-arduino.h"
 
 PROCESS(arduino_sketch, "Arduino Sketch Wrapper");
 
@@ -57,7 +59,7 @@ PROCESS_THREAD(arduino_sketch, ev, data)
 {
   PROCESS_BEGIN();
 
-  arduino_init ();
+  arduino_pwm_timer_init ();
   setup ();
   while (1) {
     loop ();

examples/osd/arduino-sketch/resource_led_pwm.c

@@ -62,6 +62,7 @@ led_pwm_handler
   const uint16_t *accept = NULL;
   uint16_t a_ctype = REST.type.APPLICATION_JSON;
   uint16_t c_ctype = REST.get_header_content_type (request);
+  uint32_t tmp = 0;
 
   /* Seems like accepted type is currently unsupported? */
   n_acc = REST.get_header_accept (request, &accept);
@@ -136,7 +137,11 @@ led_pwm_handler
           temp [sizeof (temp) - 1] = 0;
         }
         PRINTF ("GOT: %s\n", temp);
-        pwm = atoi (temp);
+        tmp = strtoul (temp, NULL, 10);
+        if (tmp > 255) {
+            tmp = 255;
+        }
+        pwm = tmp;
         PRINTF ("Setting: %d\n", pwm);
         REST.set_response_status(response, REST.status.CHANGED);
       } else {
@@ -181,6 +186,7 @@ led_period_handler
   const uint16_t *accept = NULL;
   uint16_t a_ctype = REST.type.APPLICATION_JSON;
   uint16_t c_ctype = REST.get_header_content_type (request);
+  uint32_t tmp = 0;
 
   /* Seems like accepted type is currently unsupported? */
   n_acc = REST.get_header_accept (request, &accept);
@@ -255,7 +261,14 @@ led_period_handler
           temp [sizeof (temp) - 1] = 0;
         }
         PRINTF ("GOT: %s\n", temp);
-        period_100ms = (atoi (temp) + 50) / 100;
+        tmp = (strtoul (temp, NULL, 10) + 50) / 100;
+        if (tmp > 10) {
+            tmp = 10;
+        }
+        if (tmp == 0) {
+            tmp = 1;
+        }
+        period_100ms = tmp;
         PRINTF ("Setting: %dms\n", period_100ms * 100);
         REST.set_response_status(response, REST.status.CHANGED);
       } else {

examples/osd/arduino-sketch/sketch.pde

@@ -28,20 +28,10 @@ void setup (void)
 
 void loop (void)
 {
-    static uint8_t last_pwm = 0;
+    /* Use 255 - pwm, LED on merkur-board is wired to +3.3V */
-    if (last_pwm != pwm) {
+    analogWrite (LED_PIN, 255 - pwm);
-        last_pwm = pwm;
+    printf ("clock : %u\nmillis: %lu\n", clock_time (), millis ());
-        analogWrite (LED_PIN, pwm);
+    delay (period_100ms * 100);
-        printf
+    analogWrite (LED_PIN, 255); /* OFF: LED on merkur-board is wired to +3.3V */
-            ( "TCNT3: %04X TCCR3A: %04X TCCR3B: %04X TCCR3C: %04X OCR3C: %04X\n"
+    delay (period_100ms * 100);
-            , TCNT3, TCCR3A, TCCR3B, TCCR3C, OCR3C
-            );
-    }
-
-    // Originally I wanted to sleep here to make the LED blink.
-    // Sleeping currently doesn't work, something turns off the chip.
-    // Maybe a mechanism to guard agains proto-threads taking too long?
-    //clock_wait (CLOCK_SECOND * period_100ms / 10);
-    //analogWrite (LED_PIN, 0);
-    //printf ("After write\n");
 }

platform/osd-merkur/Makefile.osd-merkur

@@ -27,7 +27,7 @@ CONTIKI_TARGET_SOURCEFILES += servo.c servo-sensor.c
 #Needed for Relay 1 to 4
 CONTIKI_TARGET_SOURCEFILES += relay.c relay-sensor.c
 # Arduino
-CONTIKI_TARGET_SOURCEFILES += wiring_digital.c wiring.c wiring_analog.c
+CONTIKI_TARGET_SOURCEFILES += wiring_digital.c wiring_analog.c
 
 CONTIKIBOARD=.
 BOOTLOADER_START = 0x1F000

platform/osd-merkur/dev/Arduino.h

@@ -69,10 +69,6 @@ extern "C"{
 #define interrupts() sei()
 #define noInterrupts() cli()
 
-#define clockCyclesPerMicrosecond() ( F_CPU / 1000000L )
-#define clockCyclesToMicroseconds(a) ( (a) / clockCyclesPerMicrosecond() )
-#define microsecondsToClockCycles(a) ( (a) * clockCyclesPerMicrosecond() )
-
 #define lowByte(w) ((uint8_t) ((w) & 0xff))
 #define highByte(w) ((uint8_t) ((w) >> 8))
 
@@ -102,10 +98,6 @@ int digitalRead(uint8_t);
 int analogRead(uint8_t);
 void analogReference(uint8_t mode);
 
-unsigned long millis(void);
-unsigned long micros(void);
-void delay(unsigned long);
-void delayMicroseconds(unsigned int us);
 unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout);
 
 void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val);

platform/osd-merkur/dev/hw-arduino.h

@@ -48,6 +48,12 @@
  *
  */
 
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+#include "contiki.h"
+
 /*
  * The OSD hardware only supports timer 3 for PWM, timer 2 is used by
  * contiki for sleep/wakeup timing and is not usable for PWM.
@@ -65,9 +71,39 @@
 #define arduino_pwm_timer_init() \
   (hwtimer_ini (3, HWT_WGM_PWM_PHASE_8_BIT, HWT_CLOCK_PRESCALER_64, 0))
 
+/*
+ * micros on arduino takes timer overflows into account.
+ * We put in the seconds counter. To get a consistent seconds / ticks
+ * value we have to disable interrupts.
+ */
+static inline uint32_t micros (void)
+{
+  uint32_t ticks;
+  uint8_t sreg = SREG;
+  cli ();
+  ticks = clock_seconds () * 1000000L
+        + clock_time () * 1000L / CLOCK_SECOND;
+  SREG = sreg;
+  return ticks;
+}
+/*
+ * millis counts only internal timer ticks since start, not trying to do
+ * something about overflows. Note that we don't try to emulate overflow
+ * behaviour of arduino implementation.
+ */
+#define millis()              (((uint32_t)clock_time())*1000L/CLOCK_SECOND)
+#define micros()              (clock_seconds()*1000L+
+#define delay(ms)             clock_delay_msec(ms)
+#define delayMicroseconds(us) clock_delay_usec(us)
+
+
 /*
  * VI settings, see coding style
  * ex:ts=8:et:sw=2
  */
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 /** @} */

platform/osd-merkur/dev/wiring.c

@@ -1,245 +0,0 @@
-/*
-  wiring.c - Partial implementation of the Wiring API for the ATmega8.
-  Part of Arduino - http://www.arduino.cc/
-
-  Copyright (c) 2005-2006 David A. Mellis
-
-  This library is free software; you can redistribute it and/or
-  modify it under the terms of the GNU Lesser General Public
-  License as published by the Free Software Foundation; either
-  version 2.1 of the License, or (at your option) any later version.
-
-  This library is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-  Lesser General Public License for more details.
-
-  You should have received a copy of the GNU Lesser General
-  Public License along with this library; if not, write to the
-  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
-  Boston, MA  02111-1307  USA
-
-  $Id$
-*/
-
-#include "wiring_private.h"
-#include "hw-arduino.h"
-
-// the prescaler is set so that timer0 ticks every 64 clock cycles, and the
-// the overflow handler is called every 256 ticks.
-#define MICROSECONDS_PER_TIMER0_OVERFLOW (clockCyclesToMicroseconds(64 * 256))
-
-// the whole number of milliseconds per timer0 overflow
-#define MILLIS_INC (MICROSECONDS_PER_TIMER0_OVERFLOW / 1000)
-
-// the fractional number of milliseconds per timer0 overflow. we shift right
-// by three to fit these numbers into a byte. (for the clock speeds we care
-// about - 8 and 16 MHz - this doesn't lose precision.)
-#define FRACT_INC ((MICROSECONDS_PER_TIMER0_OVERFLOW % 1000) >> 3)
-#define FRACT_MAX (1000 >> 3)
-
-volatile unsigned long timer0_overflow_count = 0;
-volatile unsigned long timer0_millis = 0;
-static unsigned char timer0_fract = 0;
-
-#if defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
-SIGNAL(TIM0_OVF_vect)
-#else
-SIGNAL(TIMER0_OVF_vect)
-#endif
-{
-	// copy these to local variables so they can be stored in registers
-	// (volatile variables must be read from memory on every access)
-	unsigned long m = timer0_millis;
-	unsigned char f = timer0_fract;
-
-	m += MILLIS_INC;
-	f += FRACT_INC;
-	if (f >= FRACT_MAX) {
-		f -= FRACT_MAX;
-		m += 1;
-	}
-
-	timer0_fract = f;
-	timer0_millis = m;
-	timer0_overflow_count++;
-}
-
-unsigned long millis()
-{
-	unsigned long m;
-	uint8_t oldSREG = SREG;
-
-	// disable interrupts while we read timer0_millis or we might get an
-	// inconsistent value (e.g. in the middle of a write to timer0_millis)
-	cli();
-	m = timer0_millis;
-	SREG = oldSREG;
-
-	return m;
-}
-
-unsigned long micros() {
-	unsigned long m;
-	uint8_t oldSREG = SREG, t;
-	
-	cli();
-	m = timer0_overflow_count;
-#if defined(TCNT0)
-	t = TCNT0;
-#elif defined(TCNT0L)
-	t = TCNT0L;
-#else
-	#error TIMER 0 not defined
-#endif
-
-  
-#ifdef TIFR0
-	if ((TIFR0 & _BV(TOV0)) && (t < 255))
-		m++;
-#else
-	if ((TIFR & _BV(TOV0)) && (t < 255))
-		m++;
-#endif
-
-	SREG = oldSREG;
-	
-	return ((m << 8) + t) * (64 / clockCyclesPerMicrosecond());
-}
-
-void delay(unsigned long ms)
-{
-	uint16_t start = (uint16_t)micros();
-
-	while (ms > 0) {
-		if (((uint16_t)micros() - start) >= 1000) {
-			ms--;
-			start += 1000;
-		}
-	}
-}
-
-/* Delay for the given number of microseconds.  Assumes a 8 or 16 MHz clock. */
-void delayMicroseconds(unsigned int us)
-{
-	// calling avrlib's delay_us() function with low values (e.g. 1 or
-	// 2 microseconds) gives delays longer than desired.
-	//delay_us(us);
-#if F_CPU >= 20000000L
-	// for the 20 MHz clock on rare Arduino boards
-
-	// for a one-microsecond delay, simply wait 2 cycle and return. The overhead
-	// of the function call yields a delay of exactly a one microsecond.
-	__asm__ __volatile__ (
-		"nop" "\n\t"
-		"nop"); //just waiting 2 cycle
-	if (--us == 0)
-		return;
-
-	// the following loop takes a 1/5 of a microsecond (4 cycles)
-	// per iteration, so execute it five times for each microsecond of
-	// delay requested.
-	us = (us<<2) + us; // x5 us
-
-	// account for the time taken in the preceeding commands.
-	us -= 2;
-
-#elif F_CPU >= 16000000L
-	// for the 16 MHz clock on most Arduino boards
-
-	// for a one-microsecond delay, simply return.  the overhead
-	// of the function call yields a delay of approximately 1 1/8 us.
-	if (--us == 0)
-		return;
-
-	// the following loop takes a quarter of a microsecond (4 cycles)
-	// per iteration, so execute it four times for each microsecond of
-	// delay requested.
-	us <<= 2;
-
-	// account for the time taken in the preceeding commands.
-	us -= 2;
-#else
-	// for the 8 MHz internal clock on the ATmega168
-
-	// for a one- or two-microsecond delay, simply return.  the overhead of
-	// the function calls takes more than two microseconds.  can't just
-	// subtract two, since us is unsigned; we'd overflow.
-	if (--us == 0)
-		return;
-	if (--us == 0)
-		return;
-
-	// the following loop takes half of a microsecond (4 cycles)
-	// per iteration, so execute it twice for each microsecond of
-	// delay requested.
-	us <<= 1;
-    
-	// partially compensate for the time taken by the preceeding commands.
-	// we can't subtract any more than this or we'd overflow w/ small delays.
-	us--;
-#endif
-
-	// busy wait
-	__asm__ __volatile__ (
-		"1: sbiw %0,1" "\n\t" // 2 cycles
-		"brne 1b" : "=w" (us) : "0" (us) // 2 cycles
-	);
-}
-
-void arduino_init()
-{
-	// this needs to be called before setup() or some functions won't
-	// work there
-	
-	// on the ATmega168, timer 0 is also used for fast hardware pwm
-	// (using phase-correct PWM would mean that timer 0 overflowed half as often
-	// resulting in different millis() behavior on the ATmega8 and ATmega168)
-        /*
-         * RSC: Keep timer0 for now, until we decide how to implement
-         * millis() etc in a contiki-compatible way
-         */
-
-#if defined(TCCR0A) && defined(WGM01)
-	sbi(TCCR0A, WGM01);
-	sbi(TCCR0A, WGM00);
-#endif  
-	// set timer 0 prescale factor to 64
-#if defined(__AVR_ATmega128__)
-	// CPU specific: different values for the ATmega128
-	sbi(TCCR0, CS02);
-#elif defined(TCCR0) && defined(CS01) && defined(CS00)
-	// this combination is for the standard atmega8
-	sbi(TCCR0, CS01);
-	sbi(TCCR0, CS00);
-#elif defined(TCCR0B) && defined(CS01) && defined(CS00)
-	// this combination is for the standard 168/328/1280/2560
-	sbi(TCCR0B, CS01);
-	sbi(TCCR0B, CS00);
-#elif defined(TCCR0A) && defined(CS01) && defined(CS00)
-	// this combination is for the __AVR_ATmega645__ series
-	sbi(TCCR0A, CS01);
-	sbi(TCCR0A, CS00);
-#else
-	#error Timer 0 prescale factor 64 not set correctly
-#endif
-
-	// enable timer 0 overflow interrupt
-#if defined(TIMSK) && defined(TOIE0)
-	sbi(TIMSK, TOIE0);
-#elif defined(TIMSK0) && defined(TOIE0)
-	sbi(TIMSK0, TOIE0);
-#else
-	#error	Timer 0 overflow interrupt not set correctly
-#endif
-
-        /*
-         * All other PCM timers are initialized here in a
-         * platform-specific way
-         */
-        arduino_pwm_timer_init ();
-
-        /*
-         * Removed the rest which manipulates the serial pins
-         */
-}