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//! By convention, main.zig is where your main function lives in the case that
//! you are building an executable. If you are making a library, the convention
//! is to delete this file and start with root.zig instead.
//const std = @import("std");
const gpio_registers = packed struct {
moder: u32,
otyper: u32,
ospeedr: u32,
pupdr: u32,
idr: u32,
odr: u32,
bsrr: u32,
lckr: u32,
afrl: u32,
afrh: u32,
brr: u32,
ascr: u32,
};
const gpio = struct {
port: *gpio_registers,
const mode = enum {
input,
output,
alternate,
analog,
};
pub fn set_mode(self: gpio, pin: u4, m: mode) void {
self.port.moder &= ~(@as(u32, 0x3) << (2 * pin));
const mask: u32 = switch (m) {
.input => 0,
.output => 1,
.alternate => 2,
.analog => 3
};
self.port.moder |= mask << (2 * pin);
}
pub fn toggle(self: gpio, pin: u4) void {
self.port.odr ^= @as(u32, 1) << pin;
}
};
const cpu = struct {
pub fn interrupt_disable() void {
asm volatile("cpsid i");
}
pub fn interrupt_enable() void {
asm volatile("cpsie i");
}
};
const gpioa = gpio { .port = @ptrFromInt(0x48000000) };
const rcc: *[39]u32 = @ptrFromInt(0x40021000);
export fn _start() callconv(.C) noreturn {
cpu.interrupt_disable();
rcc[19] |= 1; // gpioaen
gpioa.set_mode(5, .output);
while (true) {
gpioa.toggle(5);
}
}
export fn fault_handler() callconv(.C) void {
while (true) {}
}
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