libmaple ADC Interrupt example

#include <stdint.h>

#include <wirish.h>
#include <adc.h>
#include <nvic.h>

#define ADC_PIN 3

void
debug_str (const char *msg)
{
    // wait for enter
    while (!SerialUSB.available ())
        ;
    while (SerialUSB.available ())
        SerialUSB.read ();
    // write debug message
    SerialUSB.println (msg);
}

void
debug_int (int val)
{
    // wait for enter
    while (!SerialUSB.available ())
        ;
    while (SerialUSB.available ())
        SerialUSB.read ();
    // write debug message
    SerialUSB.println (val);
}

void (*adc12_irq_handler) (void) = NULL;

extern "C" void
__irq_adc (void)
{
    debug_str ("__irq_adc");

    if (adc12_irq_handler)
        adc12_irq_handler ();
}

void
adc12_attach_interrupt (void (*handler) (void))
{
    debug_str ("adc12_attach_interrupt");

    adc12_irq_handler = handler;
    nvic_irq_enable (NVIC_ADC_1_2);
}

void
adc12_detach_interrupt ()
{
    debug_str ("adc12_detach_interrupt");

    nvic_irq_disable (NVIC_ADC_1_2);
    adc12_irq_handler = NULL;
}

volatile uint8_t adc_done = 0;

void
adc_eoc_irq (void)
{
    debug_str ("adc_eoc_irq");

    // read and write analog signal
    uint16_t val = ADC1->regs->DR & ADC_DR_DATA;
    debug_int (val);

    adc_done = 1;
}

void
adc_run ()
{
    debug_str ("adc_run");

    adc_done = 0;

    debug_str ("starting conversion");
    ADC1->regs->CR2 |= ADC_CR2_SWSTART; // XXX maple freezes here XXX
    debug_str ("conversion started");
}

void
adc_block ()
{
    debug_str ("adc_block");

    while (!adc_done)
        ;
}

void
loop ()
{
    adc_run ();
    adc_block ();
}

void
setup ()
{
    pinMode (ADC_PIN, INPUT_ANALOG);

    // set up ADC single conversion
    ADC1->regs->SQR3 = PIN_MAP[ADC_PIN].adc_channel;
    adc_set_reg_seqlen (ADC1, 1);

    // set up interrupt
    ADC1->regs->CR1 |= ADC_CR1_EOCIE; // enable end-of-conversion interrupt
    adc12_attach_interrupt (adc_eoc_irq); // attach end-of-conversion interrupt
}

__attribute__ ((constructor)) void
premain ()
{
  init ();
}

int
main (void)
{
  setup ();

  while (true)
    loop ();

  return 0;
}