synth/arm/main.cc

#include <cstdint>

#include "xuartlite.h"

struct Gpio {
    volatile uint32_t data;
};

#define gpio0 ((Gpio*) 0x40000000)

namespace {

constexpr uintptr_t kUart0BaseAddress = 0x40001000;
XUartLite uart0;
XUartLite_Config uart0_config = {
    .DeviceId = 0,
    .RegBaseAddr = kUart0BaseAddress,
    .BaudRate = 115200,
    .UseParity = false,
    .DataBits = 8,
};

[[maybe_unused]]
void sleep(int ms) {
    for (int i = 0; i < ms; i++) {
        // sleep for 1 ms
        for (int j = 0; j < 50000; j++) {
            asm("");
        }
    }
}

}  // namespace

int main() {
    int recv = 0;
    gpio0->data = 37;

    XUartLite_CfgInitialize(&uart0, &uart0_config, uart0_config.RegBaseAddr);

    while (true) {
        uint8_t c;
        int received_bytes = XUartLite_Recv(&uart0, &c, 1);
        if (received_bytes < 1) {
            continue;
        }
        recv++;
        gpio0->data = recv & 0xff;
        XUartLite_Send(&uart0, &c, 1);
        if (c == '\r') {
            c = '\n';
            XUartLite_Send(&uart0, &c, 1);
        }
    }
}