/** Configures all hardware required for the bootloader. */
void SetupHardware(void)
{
/* Disable watchdog if enabled by bootloader/fuses */
MCUSR &= ~(1 << WDRF);
wdt_disable();
/* Disable clock division */
clock_prescale_set(clock_div_1);
/* Relocate the interrupt vector table to the bootloader section */
MCUCR = (1 << IVCE);
MCUCR = (1 << IVSEL);
LED_SETUP();
CPU_PRESCALE(0);
L_LED_OFF();
TX_LED_OFF();
RX_LED_OFF();
/* Initialize TIMER1 to handle bootloader timeout and LED tasks.
* With 16 MHz clock and 1/64 prescaler, timer 1 is clocked at 250 kHz
* Our chosen compare match generates an interrupt every 1 ms.
* This interrupt is disabled selectively when doing memory reading, erasing,
* or writing since SPM has tight timing requirements.
*/
OCR1AH = 0;
OCR1AL = 250;
TIMSK1 = (1 << OCIE1A); // enable timer 1 output compare A match interrupt
TCCR1B = ((1 << CS11) | (1 << CS10)); // 1/64 prescaler on timer 1 input
/* Initialize USB Subsystem */
USB_Init();
}
/** Main program entry point. This routine configures the hardware required by the bootloader, then continuously
* runs the bootloader processing routine until it times out or is instructed to exit.
*/
int main(void)
{
/* Save the value of the boot key memory before it is overwritten */
uint8_t bootKeyPtrVal = *bootKeyPtr;
*bootKeyPtr = 0;
/* Check the reason for the reset so we can act accordingly */
uint8_t mcusr_state = MCUSR; // store the initial state of the Status register
MCUSR = 0; // clear all reset flags
/* Watchdog may be configured with a 15 ms period so must disable it before going any further */
// MAH 8/15/12- I removed this because wdt_disable() is the first thing SetupHardware() does- why
// do it twice right in a row?
//wdt_disable();
/* Setup hardware required for the bootloader */
// MAH 8/15/12- Moved this up to before the bootloader go/no-go decision tree so I could use the
// timer in that decision tree. Removed the USBInit() call from it; if I'm not going to stay in
// the bootloader, there's no point spending the time initializing the USB.
// SetupHardware();
wdt_disable();
// Disable clock division
clock_prescale_set(clock_div_1);
// Relocate the interrupt vector table to the bootloader section
MCUCR = (1 << IVCE);
MCUCR = (1 << IVSEL);
LED_SETUP();
CPU_PRESCALE(0);
L_LED_OFF();
TX_LED_OFF();
RX_LED_OFF();
// Initialize TIMER1 to handle bootloader timeout and LED tasks.
// With 16 MHz clock and 1/64 prescaler, timer 1 is clocked at 250 kHz
// Our chosen compare match generates an interrupt every 1 ms.
// This interrupt is disabled selectively when doing memory reading, erasing,
// or writing since SPM has tight timing requirements.
OCR1AH = 0;
OCR1AL = 250;
TIMSK1 = (1 << OCIE1A); // enable timer 1 output compare A match interrupt
TCCR1B = ((1 << CS11) | (1 << CS10)); // 1/64 prescaler on timer 1 input
// MAH 8/15/12- this replaces bulky pgm_read_word(0) calls later on, to save memory.
if (pgm_read_word(0) != 0xFFFF) sketchPresent = true;
// MAH 8/15/12- quite a bit changed in this section- let's just pretend nothing has been reserved
// and all comments throughout are from me.
// First case: external reset, bootKey NOT in memory. We'll put the bootKey in memory, then spin
// our wheels for about 750ms, then proceed to the sketch, if there is one. If, during that 750ms,
// another external reset occurs, on the next pass through this decision tree, execution will fall
// through to the bootloader.
if ( (mcusr_state & (1<<EXTRF)) && (bootKeyPtrVal != bootKey) ) {
*bootKeyPtr = bootKey;
sei();
while (RunBootloader)
{
if (resetTimeout > EXT_RESET_TIMEOUT_PERIOD)
RunBootloader = false;
}
cli();
*bootKeyPtr = 0;
RunBootloader = true;
if (sketchPresent) StartSketch();
}
// On a power-on reset, we ALWAYS want to go to the sketch. If there is one.
else if ( (mcusr_state & (1<<PORF)) && sketchPresent) {
StartSketch();
}
// On a watchdog reset, if the bootKey isn't set, and there's a sketch, we should just
// go straight to the sketch.
else if ( (mcusr_state & (1<<WDRF) ) && (bootKeyPtrVal != bootKey) && sketchPresent) {
// If it looks like an "accidental" watchdog reset then start the sketch.
StartSketch();
}
// END ALL COMMENTS ON THIS SECTION FROM MAH.
/* Initialize USB Subsystem */
USB_Init();
/* Enable global interrupts so that the USB stack can function */
sei();
Timeout = 0;
while (RunBootloader)
{
CDC_Task();
USB_USBTask();
/* Time out and start the sketch if one is present */
if (Timeout > TIMEOUT_PERIOD)
RunBootloader = false;
// MAH 8/15/12- This used to be a function call- inlining it saves a few bytes.
LLEDPulse++;
uint8_t p = LLEDPulse >> 8;
if (p > 127)
p = 254-p;
p += p;
if (((uint8_t)LLEDPulse) > p)
L_LED_OFF();
else
L_LED_ON();
}
/* Disconnect from the host - USB interface will be reset later along with the AVR */
USB_Detach();
/* Jump to beginning of application space to run the sketch - do not reset */
StartSketch();
}
/** Main program entry point. This routine configures the hardware required by the bootloader, then continuously
* runs the bootloader processing routine until it times out or is instructed to exit.
*/
int main(void)
{
/* Save the value of the boot key memory before it is overwritten */
uint8_t bootKeyPtrVal = *bootKeyPtr;
*bootKeyPtr = 0;
/* Check the reason for the reset so we can act accordingly */
uint8_t mcusr_state = MCUSR; // store the initial state of the Status register
MCUSR = 0; // clear all reset flags
/* Watchdog may be configured with a 15 ms period so must disable it before going any further */
// MAH 8/15/12- I removed this because wdt_disable() is the first thing SetupHardware() does- why
// do it twice right in a row?
//wdt_disable();
/* Setup hardware required for the bootloader */
// MAH 8/15/12- Moved this up to before the bootloader go/no-go decision tree so I could use the
// timer in that decision tree. Removed the USBInit() call from it; if I'm not going to stay in
// the bootloader, there's no point spending the time initializing the USB.
// SetupHardware();
wdt_disable();
// Disable clock division
clock_prescale_set(clock_div_1);
// Relocate the interrupt vector table to the bootloader section
MCUCR = (1 << IVCE);
MCUCR = (1 << IVSEL);
LED_SETUP();
CPU_PRESCALE(0);
L_LED_OFF();
TX_LED_OFF();
RX_LED_OFF();
// Initialize TIMER1 to handle bootloader timeout and LED tasks.
// With 16 MHz clock and 1/64 prescaler, timer 1 is clocked at 250 kHz
// Our chosen compare match generates an interrupt every 1 ms.
// This interrupt is disabled selectively when doing memory reading, erasing,
// or writing since SPM has tight timing requirements.
OCR1AH = 0;
OCR1AL = 250;
TIMSK1 = (1 << OCIE1A); // enable timer 1 output compare A match interrupt
TCCR1B = ((1 << CS11) | (1 << CS10)); // 1/64 prescaler on timer 1 input
// MAH 8/15/12- this replaces bulky pgm_read_word(0) calls later on, to save memory.
if (pgm_read_word(0) != 0xFFFF) sketchPresent = true;
// MAH 26 Oct 2012- The "bootload or not?" section has been modified since the code released
// with Arduino 1.0.1. The simplest modification is the replacement of equivalence checks on
// the reset bits with masked checks, so if more than one reset occurs before the register is
// checked, the check doesn't fail and fall through to the bootloader unnecessarily.
// The second, more in depth modification addresses behavior after an external reset (i.e.,
// user pushes the reset button). The Leonardo treats all external resets as requests to
// re-enter the bootloader and wait for code to be loaded. It remains in bootloader mode for
// 8 seconds before continuing on to the sketch (if one is present). By defining RESET_DELAY
// equal to 1, this behavior will persist.
// However, if RESET_DELAY is defined to 0, the reset timeout before loading the sketch drops
// to 750ms. If, during that 750ms, another external reset occurs, THEN an 8-second delay
// in the bootloader will occur.
// This is the "no-8-second-delay" code. If this is the first time through the loop, we
// don't expect to see the bootKey in memory.
if ( (mcusr_state & (1<<EXTRF)) && (bootKeyPtrVal != bootKey) ) {
*bootKeyPtr = bootKey; // Put the bootKey in memory so if we get back to this
// point again, we know to jump into the bootloader
sei(); // Enable interrupts, so we can use timer1 to track our time in the bootloader
while (RunBootloader)
{
if (resetTimeout > EXT_RESET_TIMEOUT_PERIOD) // resetTimeout is getting incremeted
RunBootloader = false; // in the timer1 ISR.
}
// If we make it past that while loop, it's sketch loading time!
*bootKeyPtr = 0; // clear out the bootKey; from now on, we want to treat a reset like
// a normal reset.
cli(); // Disable interrupts, in case no sketch is present.
RunBootloader = true; // We want to hang out in the bootloader if no sketch is present.
if (sketchPresent) StartSketch(); // If a sketch is present, go! Otherwise, wait around
// in the bootloader until one is uploaded.
}
// On a power-on reset, we ALWAYS want to go to the sketch. If there is one.
// This is a place where the old code had an equivalence and now there is a mask.
else if ( (mcusr_state & (1<<PORF)) && sketchPresent) {
StartSketch();
}
// On a watchdog reset, if the bootKey isn't set, and there's a sketch, we should just
// go straight to the sketch.
// This is a place where the old code had an equivalence and now there is a mask.
else if ( (mcusr_state & (1<<WDRF) ) && (bootKeyPtrVal != bootKey) && sketchPresent) {
// If it looks like an "accidental" watchdog reset then start the sketch.
StartSketch();
}
/* Initialize USB Subsystem */
USB_Init();
/* Enable global interrupts so that the USB stack can function */
sei();
Timeout = 0;
while (RunBootloader)
{
CDC_Task();
USB_USBTask();
/* Time out and start the sketch if one is present */
if (Timeout > TIMEOUT_PERIOD)
RunBootloader = false;
// MAH 8/15/12- This used to be a function call- inlining it saves a few bytes.
LLEDPulse++;
uint8_t p = LLEDPulse >> 8;
if (p > 127)
p = 254-p;
p += p;
if (((uint8_t)LLEDPulse) > p)
L_LED_OFF();
else
L_LED_ON();
}
/* Disconnect from the host - USB interface will be reset later along with the AVR */
USB_Detach();
/* Jump to beginning of application space to run the sketch - do not reset */
StartSketch();
}
