synth/arm/main.cc

#include "gpio.h"

namespace {

[[maybe_unused]]
void sleep(int ms) {
    for (int i = 0; i < ms; i++) {
        // sleep for 1 ms
        for (int j = 0; j < 22000; j++) {
            asm("");
        }
    }
}

}  // namespace

extern "C" int main() {
    uint8_t cnt = 0;

    for (int i = 0; i < 256; i++) {
        gpio0->data = cnt;
        cnt++;

        sleep(125);
    }

    auto* airc = reinterpret_cast<volatile uint32_t*>(0xe000ed0c);
    uint32_t a = *airc;
    *airc = a | 0x04;

    while (1) {}
}