uart: make baudrate configurable, run at 115,200 baud

This commit is contained in:
Astro 2019-05-23 15:50:53 +02:00
parent 15883293ac
commit ea62d4fdec
2 changed files with 13 additions and 8 deletions

View File

@ -50,10 +50,11 @@ unsafe fn boot_core0() -> ! {
} }
fn main() { fn main() {
let mut uart = Uart::uart1(); let mut uart = Uart::uart1(115_200);
writeln!(uart, "Hello World\r").unwrap(); loop {
for i in 0.. { for i in 0.. {
writeln!(uart, "i={}\r", i).unwrap(); writeln!(uart, "i={}\r", i);
}
} }
let eth = eth::Eth::gem0(); let eth = eth::Eth::gem0();

View File

@ -8,12 +8,16 @@ use crate::regs::*;
mod regs; mod regs;
mod baud_rate_gen; mod baud_rate_gen;
/// Determined through experimentation. Actually supposed to be
/// 1 GHz (IO PLL) / 0x14 (slcr.UART_CLK_CTRL[DIVISOR]) = 50 MHz.
const UART_REF_CLK: u32 = 45_000_000;
pub struct Uart { pub struct Uart {
regs: &'static mut regs::RegisterBlock, regs: &'static mut regs::RegisterBlock,
} }
impl Uart { impl Uart {
pub fn uart1() -> Self { pub fn uart1(baudrate: u32) -> Self {
super::slcr::with_slcr(|| { super::slcr::with_slcr(|| {
let uart_rst_ctrl = super::slcr::UartRstCtrl::new(); let uart_rst_ctrl = super::slcr::UartRstCtrl::new();
uart_rst_ctrl.reset_uart1(); uart_rst_ctrl.reset_uart1();
@ -36,7 +40,7 @@ impl Uart {
let self_ = Uart { let self_ = Uart {
regs: regs::RegisterBlock::uart1(), regs: regs::RegisterBlock::uart1(),
}; };
self_.configure(); self_.configure(baudrate);
self_ self_
} }
@ -49,7 +53,7 @@ impl Uart {
); );
} }
pub fn configure(&self) { pub fn configure(&self, baudrate: u32) {
// Configure UART character frame // Configure UART character frame
// * Disable clock-divider // * Disable clock-divider
// * 8-bit // * 8-bit
@ -67,7 +71,7 @@ impl Uart {
self.disable_rx(); self.disable_rx();
self.disable_tx(); self.disable_tx();
baud_rate_gen::configure(&self.regs, 50_000_000, 9_600); baud_rate_gen::configure(&self.regs, UART_REF_CLK, baudrate);
// Enable controller // Enable controller
self.reset_rx(); self.reset_rx();