unsigned int baud_time_get()
{
#ifdef ___MAPLE
timer4.pause();
unsigned int tmp = timer4.getCount(); //get current timer count
timer4.setCount(0); // reset timer count
timer4.refresh();
timer4.resume();
#endif
#ifdef ___ARDUINO
TCCR1B &= 0xF8; // Clear CS10/CS11/CS12 bits, stopping the timer
unsigned int tmp = int(TCNT1/2); // get current timer count, dividing by two
// because Arduino timer is counting at 2Mhz instead of 1Mhz
// due to limited prescaler selection
tmp += 0x8000 * baudOverflow; // if timer overflowed, we will add 0xFFFF/2
TCNT1 = 0; // reset timer count
baudOverflow = false; // reset baudOverflow after resetting timer
TCCR1B |= (1 << CS11); // Configure for 8 prescaler, restarting timer
#endif
#ifdef ___TEENSY
unsigned int tmp = int(FTM0_CNT*2.8);
FTM0_CNT = 0x0;
#endif
return tmp;
}
void setup() {
// Setup our pins
pinMode(BOARD_LED_PIN, OUTPUT);
pinMode(VGA_R, OUTPUT);
pinMode(VGA_G, OUTPUT);
pinMode(VGA_B, OUTPUT);
pinMode(VGA_V, OUTPUT);
pinMode(VGA_H, OUTPUT);
digitalWrite(VGA_R, LOW);
digitalWrite(VGA_G, LOW);
digitalWrite(VGA_B, LOW);
digitalWrite(VGA_H, HIGH);
digitalWrite(VGA_V, HIGH);
// Fill the logo array with color patterns corresponding to its
// truth value. Note that we could get more tricky here, since
// there are 3 bits of color.
for (int y = 0; y < y_max; y++) {
for (int x = 0; x < x_max; x++) {
logo[y][x] = logo[y][x] ? ON_COLOR : OFF_COLOR;
}
}
// This gets rid of the majority of the interrupt artifacts;
// there's still a glitch for low values of y, but let's not worry
// about that. (Probably due to the hackish way vsync is done).
SerialUSB.end();
systick_disable();
// Configure
timer.pause(); // while we configure
timer.setPrescaleFactor(1); // Full speed
timer.setMode(TIMER_CH1, TIMER_OUTPUT_COMPARE);
timer.setMode(TIMER_CH2, TIMER_OUTPUT_COMPARE);
timer.setMode(TIMER_CH3, TIMER_OUTPUT_COMPARE);
timer.setMode(TIMER_CH4, TIMER_OUTPUT_COMPARE);
timer.setOverflow(2287); // Total line time
timer.setCompare(TIMER_CH1, 200);
timer.attachInterrupt(TIMER_CH1, isr_porch);
timer.setCompare(TIMER_CH2, 300);
timer.attachInterrupt(TIMER_CH2, isr_start);
timer.setCompare(TIMER_CH3, 2170);
timer.attachInterrupt(TIMER_CH3, isr_stop);
timer.setCompare(TIMER_CH4, 1); // Could be zero, I guess
timer.attachInterrupt(TIMER_CH4, isr_update);
timer.setCount(0); // Ready...
timer.resume(); // Go!
}
void baud_timer_restart()
{
#ifdef ___MAPLE
timer4.setCount(0);
timer4.refresh();
#endif
#ifdef ___ARDUINO
TCNT1 = 0;
baudOverflow = false;
#endif
#ifdef ___TEENSY
FTM0_CNT = 0x0;
#endif
}
//Timer control routines
void baud_timer_init()
{
#ifdef ___MAPLE
timer4.pause(); // Pause the timer while configuring it
timer4.setMode(TIMER_CH1, TIMER_OUTPUT_COMPARE); // Set up interrupt on channel 1
timer4.setCount(0); // Reset count to zero
timer4.setPrescaleFactor(72); // Timer counts at 72MHz/72 = 1MHz 1 count = 1uS
timer4.setOverflow(0xFFFF); // reset occurs at 15.259Hz
timer4.refresh(); // Refresh the timer's count, prescale, and overflow
timer4.resume(); // Start the timer counting
#endif
#ifdef ___ARDUINO
cli(); // stop interrupts during configuration
TCCR1A = 0; // Clear TCCR1A register
TCCR1B = 0; // Clear TCCR1B register
TCNT1 = 0; // Initialize counter value
OCR1A = 0xFFFF; // Set compare match register to maximum value
TCCR1B |= (1 << WGM12); // CTC mode
// We want 1uS ticks, for 16MHz CPU, we use prescaler of 16
// as 1MHz = 1uS period, but Arduino is lame and only has
// 3 bit multiplier, we can have 8 (overflows too quickly)
// or 64, which operates at 1/4 the desired resolution
TCCR1B |= (1 << CS11); // Configure for 8 prescaler
TIMSK1 |= (1 << OCIE1A); // enable compare interrupt
sei(); // re-enable interrupts
#endif
#ifdef ___TEENSY
FTM0_MODE |= FTM_MODE_WPDIS;
FTM0_CNT = 0;
FTM0_CNTIN = 0;
FTM0_SC |= FTM_SC_PS(7);
FTM0_SC |= FTM_SC_CLKS(1);
FTM0_MOD = 0xFFFF;
FTM0_MODE |= FTM_MODE_FTMEN;
/*
PIT_LDVAL1 = 0x500000;
PIT_TCTRL1 = TIE;
PIT_TCTRL1 |= TEN;
PIT_TFLG1 |= 1;
*/
#endif
}
//invoked as configured by the DMA mode flags.
void dma_isr()
{
dma_irq_cause cause = dma_get_irq_cause(DMA1, DMA_CH1);
//using serialusb to print messages here is nice, but
//it takes so long, we may never exit this isr invocation
//before the next one comes in.. (dma is fast.. m'kay)
timer4.setCount(0); // clear counter
if(ppm_timeout) ppm_timeout=0;
switch(cause)
{
case DMA_TRANSFER_COMPLETE:
// Transfer completed
//SerialUSB.println("DMA Complete");
dma_data_captured=1;
break;
case DMA_TRANSFER_HALF_COMPLETE:
// Transfer is half complete
SerialUSB.println("DMA Half Complete");
break;
case DMA_TRANSFER_ERROR:
// An error occurred during transfer
SerialUSB.println("DMA Error");
dma_data_captured=1;
break;
default:
// Something went horribly wrong.
// Should never happen.
SerialUSB.println("DMA WTF");
dma_data_captured=1;
break;
}
}
void init_ppm_timer()
{
timer4.pause();
timer4.setPrescaleFactor(TIMER_PRESCALE);
timer4.setOverflow(65535);
timer4.setCount(0);
// use channel 2 to detect when we stop receiving
// a ppm signal from the encoder.
timer4.setMode(TIMER_CH2, TIMER_OUTPUT_COMPARE);
timer4.setCompare(TIMER_CH2, 65535);
timer4.attachCompare2Interrupt(ppm_timeout_isr);
timer4.refresh();
//capture compare regs TIMx_CCRx used to hold val after a transition on corresponding ICx
//when cap occurs, flag CCXIF (TIMx_SR register) is set,
//and interrupt, or dma req can be sent if they are enabled.
//if cap occurs while flag is already high CCxOF (overcapture) flag is set..
//CCIX can be cleared by writing 0, or by reading the capped data from TIMx_CCRx
//CCxOF is cleared by writing 0 to it.
//Clear the CC1E bit to disable capture from the counter as we set it up.
//CC1S bits aren't writeable when CC1E is set.
//CC1E is bit 0 of CCER (page 401)
bitClear(r.gen->CCER,0);
//Capture/Compare 1 Selection
// set CC1S bits to 01 in the capture compare mode register 1.
// 01 selects TI1 as the input to use. (page 399 stm32 reference)
// (assuming here that TI1 is D16, according to maple master pin map)
//CC1S bits are bits 1,0
bitClear(r.gen->CCMR1, 1);
bitSet(r.gen->CCMR1, 0);
//Input Capture 1 Filter.
// need to set IC1F bits according to a table saying how long
// we should wait for a signal to be 'stable' to validate a transition
// on the input.
// (page 401 stm32 reference)
//IC1F bits are bits 7,6,5,4
bitClear(r.gen->CCMR1, 7);
bitClear(r.gen->CCMR1, 6);
bitSet(r.gen->CCMR1, 5);
bitSet(r.gen->CCMR1, 4);
//sort out the input capture prescaler IC1PSC..
//00 no prescaler.. capture is done at every edge detected
bitClear(r.gen->CCMR1, 3);
bitClear(r.gen->CCMR1, 2);
//select the edge for the transition on TI1 channel using CC1P in CCER
//CC1P is bit 1 of CCER (page 401)
// 0 = rising (non-inverted. capture is done on a rising edge of IC1)
// 1 = falling (inverted. capture is done on a falling edge of IC1)
bitClear(r.gen->CCER,1);
//set the CC1E bit to enable capture from the counter.
//CC1E is bit 0 of CCER (page 401)
bitSet(r.gen->CCER,0);
//enable dma for this timer..
//sets the Capture/Compare 1 DMA request enable bit on the DMA/interrupt enable register.
//bit 9 is CC1DE as defined on page 393.
bitSet(r.gen->DIER,9);
}
