main.c

来自「旋转16个LED灯控制程序」· C语言 代码 · 共 993 行 · 第 1/2 页

  MCUCR = _BV(ISC11) & ~_BV(ISC01) & ~_BV(ISC00) &  ~_BV(ISC10);

  // Activate the interrupts by setting the General Interrupt Mask
  // Register (Page 63)
  
  GIMSK = _BV(INT1) | _BV(INT0);

  // The ATMEL has built-in timers that can trigger an interrupt.
  // SpokePOV uses them to update the LEDs 256 times per rotation.
  
  // Timer 0 is set to update at a rate system-clock / 256 and
  // interrupt when it overflows (8 bit).  This means that it
  // triggers every 65536 cycles.
  
  TCCR0A = 0;				// normal, overflow (count up to 256 == num pixels)
  TCCR0B = _BV(CS02);		// clk/256
  TIMSK |= _BV(TOIE0);		// turn on overflow interrupt
  
  // Timer 1 (T1) is the pixel timer, which is used to update the
  // LEDs 256 times per rotation.  It's set up as a normal timer
  // as well.  See Page 108&71; it is apparently being set into CTC
  // mode 4.  This means that the counter is compared to a 16-bit value
  // and interrupts when it reaches this value.
  //
  // Adjusting this value is how the SpokePOV compensates for
  // changes in the rotation speed of the device.
  //
  // Note that at this point, the timer is initialized, but not
  // activated.
  
  TCCR1A = 0;
  TCCR1B = _BV(WGM12);

  // Clear the debounce values, which I haven't sussed out yet.
  
  hall_debounce = 0;
  sensor_timer = 0;
  
}

// Delay for a specified number of milliseconds using some
// assembly code.  Will this be dependant on the clock speed?

void delay_ms(unsigned char ms)
{
  unsigned short delay_count = F_CPU / 4000;
  
  unsigned short cnt;
  asm volatile ("\n"
		"L_dl1%=:\n\t"
		"mov %A0, %A2\n\t"
		"mov %B0, %B2\n"
		"L_dl2%=:\n\t"
		"sbiw %A0, 1\n\t"
		"brne L_dl2%=\n\t"
		"wdr\n\t"
		"dec %1\n\t" "brne L_dl1%=\n\t":"=&w" (cnt)
		:"r"(ms), "r"((unsigned short) (delay_count))
		);
}

// All of the following routines have been modified so they
// only deal with the front leds, for speed, and to save
// code space!

// Sends the 4-byte LED pixel data block out
// over the serial link.  Front LEDs only

void clock_leds(void) {

  // QUESTION: this code sends 4 bytes over the link to
  // update the LEDs.  But spieeprom_read_into_leds() in
  // eeprom.c sends 5.  Why the difference?
  
  // Also, to get the character set to display properly,
  // I had to send out the bytes in a slightly shuffled
  // order.  Not sure WHY this is so, but it works...
  
  spi_transfer(fleds[2]);
  spi_transfer(fleds[3]);
  spi_transfer(fleds[0]);
  spi_transfer(fleds[1]);
 
 LATCH_SELECT_PORT |= _BV(FRONT);
  NOP; NOP; NOP; NOP;
  LATCH_SELECT_PORT &= ~_BV(FRONT);
}

// Turn on a single LED, turning off all the other LEDs

void set_led(uint8_t led) {

  fleds[0] = fleds[1] = fleds[2] = fleds[3] = 0xFF;
  fleds[led/8] = ~_BV(led%8);

  clock_leds();
}

// Set all the LEDs on a side to have the same
// repeating 8-bit value (ie: 0x00 = all on, 0xFF = all off)
// Added by RJW to permit a more comprehensive reset display

void set_all(uint8_t blockValue) {

  fleds[0] = fleds[1] = fleds[2] = fleds[3] = blockValue;
  
  clock_leds();
}

// Test the LEDs on power-on.  Runs through them
// quickly, then displays alternating LEDs, and
// finally puts them all on.  This test sequence
// is slightly modified from the original, and
// makes it easier to see problems with the LEDs.

void test_leds(void) {
  uint8_t i;

  // Quick run through the LEDs
  
  for(i=0; i< 33; i++) {
    set_led(i);
    delay_ms(10);
  }
  
  // Set groups of 8 LEDs to the same value.
  // Note that the LED state is the opposite
  // of what you might expect:
  //
  // 0 bits = on, 1 bits = off!
  
  // Light every other LED
  
  set_all(0xAA);
  delay_ms(50);
  
  // Now light the other LEDs
  
  set_all(0x55);
  set_all(0x55);
  delay_ms(50);
  
  // Now light all LEDs
  
  set_all(0x00);
  delay_ms(255);
  delay_ms(255);
  
  // likely the 1-second reset timer will go off before
  // this ends.  But no biggy, since if it does, it'll
  // reset the LEDs..
  
}
 
 
int main(void) {

  uint8_t buff[16];		// a buffer of 16 bytes read/written to EEPROM
  uint8_t i, n;			// loop variables
  uint8_t cmd;			// the reason we reset
  uint16_t addr;		// address to read/write in EEPROM

  // MCUSR is the MCU Status Register (page 40).  It tells us
  // why we reset, and a reset is the only way to get here.
  
  cmd = MCUSR;
  
  // The first order of business is to tell the chip that
  // we've got things under control.
  
  MCUSR = 0;
  
  // Turn on watchdog timer immediately, this protects against
  // a 'stuck' system by resetting it.
  
  // WDTCSR is the Watchdog Timer Control Register (page 45).
  // We set it so that it'll generate a watchdog interrupt
  // every second.  The idea is that if things mess up,
  // the watchdog will kickstart us.
  
  WDTCSR = _BV(WDE) | _BV(WDP2) | _BV(WDP1); // 1 second
  
  // Initialize the various pins of the ATMEL, and set up
  // the interrupts.
  
  ioinit();
  
  // We saved the reason for the reset of the chip.  If
  // it's a power-on, then we run a test pattern through
  // the LEDs.  Note that because we've set a 1-second
  // watchdog timer (in ioinit), if this test sequence
  // takes more than a second, the chip will reset.  But
  // since we'll know it isn't a power-on, the test
  // sequence won't run...
  
  if ((cmd & _BV(PORF)) != 0)
    test_leds();

  // display the reason for the reset on the LEDs.
  
  set_led(cmd+2);

  // enable the interrupts.  I think this is not needed
  // since it'll immediately be done by the loop, below.
  
  sei();
  
  // Now loop processing commands that come in over the
  // dongle.  This is how the EEPROMs are programmed.
  
  while (1) {
  
  	// Enable interrupts again
  	
  	sei();
    cmd = tx_computer_byte(0);

	// This break is the only way out of
	// this loop.  If it executes (probably because of
	// a timeout in tx_computer_byte()), then there is
	// no way back other than resetting the chip by
	// a long button-push.
	
    if (cmd == 0)
      break;
    else
    
      // Disable interrupts during command processing.
      
      cli();

	// Sensor_timer does double-duty here, as a timeout counter for
	// the communications link.  But this is OK since we never do
	// comm and display at the same time...
	
	// POSSIBLE BUG: it isn't cleared before the original cmd
	// byte read, and since interrupts are off, it won't be
	// incremented by the interrupt routine!
	
    sensor_timer = 0;      // overloaded to reset communications timeout

    switch (cmd) {

		// Read either a single byte, or 16 bytes, from either
		// the external or internal EEPROM.  If the high bit of
		// the address is 1, then it's an internal read.
		
		case COMP_CMD_RDEEPROM:
		case COMP_CMD_RDEEPROM16:

		  if  (cmd == COMP_CMD_RDEEPROM16)
			n = 16;
		  else
			n = 1;
	
		  // read 2 bytes to get the address
		  
		  addr = tx_computer_byte(0);
		  addr <<= 8;
		  addr |= tx_computer_byte(0);
		  
		  // internal or external?
		  
		  if ((addr & 0x8000) != 0) {
		  
		  	// there are only 256 bytes of internal eeprom
		  	
			tx_computer_byte(internal_eeprom_read(addr & 0xFF));
			
		  } else {
		
			// read and transfer 1 or 16 bytes
			
			spieeprom_read(addr, buff, n);
			for (i=0; i<n; i++) {
			  tx_computer_byte(buff[i]);
			}
			
		  }
	
		  // Tell the PC we're copacetic
		  
		  tx_computer_byte(COMP_SUCCESS);
		  break;
	
		// Write either a single byte or a block of 16.  Same
		// idea as above...
		
		case COMP_CMD_WREEPROM:
		case COMP_CMD_WREEPROM16:
		  
		  if (cmd == COMP_CMD_WREEPROM16)
			n = 16;
		  else
			n = 1;
	
		  addr = tx_computer_byte(0);
		  addr <<= 8;
		  addr |= tx_computer_byte(0);
		  
		  // Give a visual indication that we're loading data
		  
		  set_led((addr/16)%32); 
		  
		  // Receive the bytes
		  
		  for (i=0; i<n; i++) {
			buff[i] = tx_computer_byte(0);
		  }
	
		  // Tell the PC we got the data...
		  
		  tx_computer_byte(COMP_SUCCESS);
	
		  // ...and actually do the write
		  
		  if ((addr & 0x8000) != 0) {
			internal_eeprom_write(addr & 0xFF, buff[0]);
		  } else {
			spieeprom_write(addr, buff, n);
		  }
		  break;
    }
  
  }

  // Loop until we timeout, at which point the ATMEL is
  // put to sleep.  If the communications routine timed
  // out, or the user pressed the button for >500ms,
  // then sensor_timer will be 0xFFFF and we'll immediately
  // sleep.
  
  while (1) {
  
    // Reset the watchdog Timer.
    //
    // QUESTION: What's with toggling the PD0 output line here?
    // it doesn't seem to be connected to anything according to
    // the circuit diagram...
    
    PORTD |= 0x1;
    asm("wdr");
    PORTD &= ~0x1;

	// If the sensor_timer (incremented by TIMER0) maxes out
	// (in about 3 minutes), then sleep everything.
	
    if (sensor_timer == 0xFFFF) {
      
      // Avoid pesky interruptions
      
      cli();
      
      // Turn off all LEDs - I guess LED 0 is one of the "invisible ones"
      
      set_led(0);
      
      // Turn off power to the Hall Effect sensor.
      
      SENSOR_PORT &= ~_BV(SENSORPOWER);
      
      // Deselect EEPROM
      
      SPIEE_CS_PORT |= _BV(SPIEE_CS);      // pull CS high to deselect
      
      // Turn off Watchdog (must be restarted when we get the wakeup)
      // Wakeup will be via the button interrupt.
      
      WDTCSR |= _BV(WDCE) | _BV(WDE);
      WDTCSR = 0;
      MCUCR |= _BV(SM1) | _BV(SM0) | _BV(SE);
      
      // Re-enable interrupts so we can get the wakeup!
      
      sei();
     
      // Go into sleep mode
      
      asm("sleep");
    }
  }
  PORTD |= 0x2;
}

// Talk to the PC.  First a byte is sent, then a byte
// is received.  This is a simple form of handshaking.
//
// The assembly wdr instruction resets the watchdog
// timer so it won't cause everything to abort.
//
// POSSIBLE BUG: this function quits when sensor_timer
// maxes out.  But sensor_timer is incremented in an
// interrupt routine, and AFAICT interrupts are turned
// off in the communications loop (except for the
// cmd read, which is possibly the only time it's
// needed).  But in addition, it isn't cleared before
// that read, so the timeout may occur a lot faster
// that expected.
//
// POSSIBLE BUG: if it does time out, then the returned
// value v is undefined.
//
// I won't worry at this point about figuring out how
// this works!

uint8_t tx_computer_byte(uint8_t b) {
  uint8_t v;

  DDRA = 0x0;           				// outputs
  DDRB = 0x5F;          				// input on MOSI/DI (for SPI), all others output
  USICR = _BV(USIWM0) | _BV(USICS1);
  USIDR = b;                 			// transfer 0x0
  USISR = _BV(USIOIF);       			// ready
  while (! (USISR & _BV(USIOIF)) ) {
    asm("wdr");

    if (sensor_timer == 0xFFFF) { 
      stopcomputertx = 1;
    }
    
    if (stopcomputertx) {
      break;
    }
    
  }

  v = USIDR;

  DDRB = 0xDF; 
  USICR = 0;

  return v;
}

// Move data over the serial link (to the 1K/4K EEPROM or the
// LED shift registers, or both!)  This is black magic to me!

uint8_t spi_transfer(uint8_t c) {

  USIDR = c;
  USISR = _BV(USIOIF);

  while (! (USISR & _BV(USIOIF))) {

    USICR = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK) | _BV(USITC);
    //NOP;  // slow down so that the eeprom isnt overwhelmed

  }

  return USIDR;

}

// Read the internal EEPROM

uint8_t internal_eeprom_read(uint8_t addr) {

  loop_until_bit_is_clear(EECR, EEWE);	// Wait for last write to finish

  EEAR = addr;							// Store address to read
  EECR |= _BV(EERE);					// Trigger the EEPROM read - this takes only one
										// cycle, so the result can immediately be returned!
  return EEDR;							

}

// Write the internal EEPROM

void internal_eeprom_write(uint8_t addr, uint8_t data) {

  loop_until_bit_is_clear(EECR, EEWE);	// Wait for last write to finish

  EEAR = addr;							// Store address to write
  EEDR = data;							// and the data
  
  // The following register bitflips are time-critical and must
  // happen within 4 cycles of each other.  For this reason,
  // interrupts cannot be allowed here.
  
  // Note: Page 19 refers to EEWE as EEPE and EEMWE as EEMPE.

  // POSSIBLE BUG: EEPM{0,1} bits in EECR define what programming
  // mode the EEPROM is in.  They do not have a defined initial
  // value if the EEPROM is programming when a reset comes in.
  // This is a tiny time window, but should they be explicitly
  // cleared?
  
  cli();                // Turn off interrupts 
  
  EECR |= _BV(EEMWE);   // Master enable, unlocks ability to write to EEPROM
  EECR |= _BV(EEWE);	// Program enable, actually does it.
  
  sei();                // Turn on interrupts again
}