Files
ece-475-tm4c123gxl-rust/src/main.rs
2022-04-22 03:11:45 -04:00

269 lines
7.6 KiB
Rust

#![no_std]
#![no_main]
#![feature(default_alloc_error_handler)]
use core::{
alloc::{GlobalAlloc, Layout},
arch::asm,
cell::UnsafeCell,
ptr,
};
// Bump pointer allocator for *single* core systems
struct BumpPointerAlloc {
head: UnsafeCell<usize>,
end: usize,
}
unsafe impl Sync for BumpPointerAlloc {}
unsafe impl GlobalAlloc for BumpPointerAlloc {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
// `interrupt::free` is a critical section that makes our allocator safe
// to use from within interrupts
interrupt::free(|_| {
let head = self.head.get();
let size = layout.size();
let align = layout.align();
let align_mask = !(align - 1);
// move start up to the next alignment boundary
let start = (*head + align - 1) & align_mask;
if start + size > self.end {
// a null pointer signal an Out Of Memory condition
ptr::null_mut()
} else {
*head = start + size;
start as *mut u8
}
})
}
unsafe fn dealloc(&self, _: *mut u8, _: Layout) {
// this allocator never deallocates memory
}
}
// Declaration of the global memory allocator
// NOTE the user must ensure that the memory region `[0x2000_0100, 0x2000_0200]`
// is not used by other parts of the program
#[global_allocator]
static HEAP: BumpPointerAlloc = BumpPointerAlloc {
head: UnsafeCell::new(0x2000_0100),
end: 0x2000_0200,
};
// TODO: remove or fix
// #[macro_use]
extern crate alloc;
use alloc::string::String;
use cortex_m::interrupt;
use panic_halt as _; // you can put a breakpoint on `rust_begin_unwind` to catch panics
use cortex_m_rt::entry;
use driver_and_task_library::{
setup_board, Function, GPIOPortOptions, Pin, Port, Pull, ReadablePinOptions,
WritablePinOptions, H, L,
};
const SYSCTL_RCGC1_R: *mut u32 = 0x400FE104 as *mut u32;
/// UART0 data register
const UART0_DR_R: *mut u32 = 0x4000C000 as *mut u32;
/// UART0 flag register
const UART0_FR_R: *mut u32 = 0x4000C018 as *mut u32;
/// UART0 integer baud rate register
const UART0_IBRD_R: *mut u32 = 0x4000C024 as *mut u32;
/// UART0 fractional baud rate register
const UART0_FBRD_R: *mut u32 = 0x4000C028 as *mut u32;
/// UART0 line control register
const UART0_LCRH_R: *mut u32 = 0x4000C02C as *mut u32;
/// UART0 control register
const UART0_CTL_R: *mut u32 = 0x4000C030 as *mut u32;
const GPIO_PORTA_AFSEL_R: *mut u32 = 0x40004420 as *mut u32;
const GPIO_PORTA_DEN_R: *mut u32 = 0x4000451C as *mut u32;
/// UART0 Clock Gating Control
const SYSCTL_RCGC1_UART0: u32 = 0x00000001;
/// UART Enable
const UART_CTL_UARTEN: u32 = 0x00000001;
/// 8 bit word length
const UART_LCRH_WLEN_8: u32 = 0x00000060;
/// UART Enable FIFOs
const UART_LCRH_FEN: u32 = 0x00000010;
/// UART Transmit FIFO Full
const UART_FR_TXFF: u32 = 0x00000020;
/// UART Receive FIFO Empty
const UART_FR_RXFE: u32 = 0x00000010;
/// Pins 0 and 1
const PINS_0_AND_1: u32 = 0b0000_0011;
fn uart0_init() {
unsafe {
// activate UART0
ptr::write_volatile(
SYSCTL_RCGC1_R,
ptr::read_volatile(SYSCTL_RCGC1_R) | SYSCTL_RCGC1_UART0,
);
// write_color(MAGENTA);
// For some reason, 7 no-ops are needed to stall the CPU while UART is enabled
for _ in 0..7 {
asm!("nop");
}
// TODO / WIP: done up to here
// disable UART while setting it up
ptr::write_volatile(
UART0_CTL_R,
ptr::read_volatile(UART0_CTL_R) & !UART_CTL_UARTEN,
);
// IBRD = int(16,000,000 / (16 * 115,200)) = int(8.680)
// ptr::write_volatile(UART0_IBRD_R, 8);
ptr::write_volatile(UART0_IBRD_R, 8);
// ignore: // FBRD = int(0.1267 * 64 + 0.5) = 8
// FBRD = round(0.5104 * 64 ) = 33 --- that ain't the number you wrote but ok
// ptr::write_volatile(UART0_FBRD_R, 44);
ptr::write_volatile(UART0_FBRD_R, 44);
// 8 bit word length (no parity bits, one stop bit, FIFOs)
// ptr::write_volatile(UART0_LCRH_R, UART_LCRH_WLEN_8|UART_LCRH_FEN);
ptr::write_volatile(UART0_LCRH_R, UART_LCRH_WLEN_8 | UART_LCRH_FEN);
// enable UART since it's been set up
ptr::write_volatile(
UART0_CTL_R,
ptr::read_volatile(UART0_CTL_R) | UART_CTL_UARTEN,
);
// enable alt funct on PA1-0
ptr::write_volatile(
GPIO_PORTA_AFSEL_R,
ptr::read_volatile(GPIO_PORTA_AFSEL_R) | PINS_0_AND_1,
);
// enable digital I/O on PA1-0
ptr::write_volatile(
GPIO_PORTA_DEN_R,
ptr::read_volatile(GPIO_PORTA_AFSEL_R) | PINS_0_AND_1,
);
}
}
fn uart0_out_char_blocking(c: u8) {
loop {
let fr = unsafe { ptr::read_volatile(UART0_FR_R) };
if (fr & UART_FR_TXFF) == 0 {
break;
}
}
unsafe {
ptr::write_volatile(UART0_DR_R, c as u32);
}
}
fn uart0_out_string_blocking(s: &str) {
for c in s.bytes() {
uart0_out_char_blocking(c);
}
}
fn uart0_in_char_blocking() -> u8 {
loop {
let fr = unsafe { ptr::read_volatile(UART0_FR_R) };
if (fr & UART_FR_RXFE) == 0 {
break;
}
}
unsafe { ptr::read_volatile(UART0_DR_R) as u8 }
}
const WHITE: [bool; 3] = [H, H, H];
const BLACK: [bool; 3] = [L, L, L];
const RED: [bool; 3] = [H, L, L];
const YELLOW: [bool; 3] = [H, H, L];
const GREEN: [bool; 3] = [L, H, L];
const CYAN: [bool; 3] = [L, H, H];
const BLUE: [bool; 3] = [L, L, H];
const MAGENTA: [bool; 3] = [H, L, H];
#[entry]
fn main() -> ! {
let mut board = setup_board();
let mut port_a = board.setup_gpio_port(Port::A, GPIOPortOptions);
let mut port_f = board.setup_gpio_port(Port::F, GPIOPortOptions);
let switches = port_f.setup_readable_pins(
[Pin::Zero, Pin::Four],
ReadablePinOptions {
function: Function::Digital,
pull: Pull::Up,
},
);
let mut rgb_led = port_f.setup_writable_pins(
[Pin::One, Pin::Three, Pin::Two],
WritablePinOptions {
function: Function::Digital,
},
);
// TODO: finish this
uart0_init();
// WIP: page 682
port_a.setup_writable_pins(
[Pin::One],
WritablePinOptions {
function: Function::UART,
},
);
uart0_out_string_blocking("Hi, this is after!! uart setup_writable_pins\r\n\r\n");
port_a.setup_readable_pins(
[Pin::Zero],
ReadablePinOptions {
function: Function::UART,
pull: Pull::Neither,
},
);
uart0_out_string_blocking("Hi, this is after uart setup_readable_pins\r\n\r\n");
let rainbow = [RED, YELLOW, GREEN, CYAN, BLUE, MAGENTA];
// TODO: WIP: debugging
let s = String::from("\r\ntesting a static string!!!\r\n\r\n\r\n");
uart0_out_string_blocking(&s);
loop {
// uart0_out_string_blocking("Hi still running down here!\r\n");
match switches.read_all() {
[L, L] => rgb_led.write_all(WHITE),
[L, H] => rgb_led.write_all(BLUE),
[H, L] => rgb_led.write_all(RED),
[H, H] => rgb_led.write_all(BLACK),
}
// uart0_out_string(&format!("The switches read {:?}", switches.read_all()));
// for _ in 0..1000000 {
// unsafe {
// asm!("nop");
// }
// }
let new_char = uart0_in_char_blocking();
uart0_out_string_blocking("New character received: ");
uart0_out_char_blocking(new_char);
uart0_out_string_blocking("\r\n");
}
}