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const PERIPHERAL_BASE = @import("board.zig").PERIPHERAL_BASE;
const FSEL = PERIPHERAL_BASE + 0x200000;
const SET = PERIPHERAL_BASE + 0x20001c;
const CLR = PERIPHERAL_BASE + 0x200028;
const PULL = PERIPHERAL_BASE + 0x2000e4;
const MAX_PIN = 53;
fn call(
pin: comptime_int,
value: u32,
base: comptime_int,
field_size: comptime_int,
) void {
const field_mask: u32 = (1 << field_size) - 1;
if (pin > MAX_PIN) @compileError("invalid pin number");
const n_fields = 32 / field_size;
const reg = base + (pin / n_fields) * 4;
const shift = (pin % n_fields) * field_size;
const mmio_ptr: *volatile u32 = @ptrFromInt(reg);
var reg_val = mmio_ptr.*;
reg_val &= ~(field_mask << shift);
reg_val |= value << shift;
mmio_ptr.* = reg_val;
}
pub fn write(pin: comptime_int, value: bool) void {
if (value) {
call(pin, 1, SET, 1);
} else {
call(pin, 1, CLR, 1);
}
}
pub const Pull = enum {
none,
up,
down,
};
pub fn setPull(pin: comptime_int, pull: Pull) void {
call(pin, @intFromEnum(pull), PULL, 2);
}
pub const Function = enum {
input,
output,
alt5,
alt4,
alt0,
alt1,
alt2,
alt3,
};
pub fn setFunction(pin: comptime_int, function: Function) void {
call(pin, @intFromEnum(function), FSEL, 3);
}
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