src/uart.rs


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use crate::cpu::*;
const UART0_DR: u32    = 0x3F201000;
const UART0_FR: u32    = 0x3F201018;
const UART0_CR: u32    = 0x3F201030;
const UART0_ICR: u32   = 0x3F201044;
const UART0_IBRD: u32  = 0x3F201024;
const UART0_FBRD: u32  = 0x3F201028;
const UART0_LCRH: u32  = 0x3F20102C;
const UART0_IMSC: u32  = 0x3F201038;
const GPPUD: u32       = 0x3F200094;
const GPPUDCLK0: u32   = 0x3F200098;

pub fn uart_init() {
	store32(UART0_CR, 0);
	store32(GPPUD, 0);
	spin_for_n_cycles(150);
	store32(GPPUDCLK0, (1 << 14) | (1 << 15));
	spin_for_n_cycles(150);
	store32(GPPUDCLK0, 0);
	store32(UART0_ICR, 0x7FF);
	store32(UART0_IBRD, 9);
	store32(UART0_FBRD, 49);
	store32(UART0_LCRH, (1<<4) | (1<<5) | (1<<6));
	store32(UART0_IMSC, (1<<1) | (1<<4) | (1<<5) | (1<<6) | (1<<7) | (1<<8) | (1<<9) | (1<<10));
	store32(UART0_CR, (1<<0) | (1<<8) | (1<<9));
}

pub fn write_char(ch: u8) {
	while load32(UART0_FR) & 0x20 != 0 {
		nop();
	}
	store32(UART0_DR, ch as u32);
}