jacob/ece-475-tm4c123gxl-rust
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trying out uart and asm

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This commit is contained in:
J / Jacob Babich
2022-04-17 13:18:43 -04:00
parent ac0e1067d0
commit db033c7ee6
1 changed files with 46 additions and 24 deletions
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70
src/main.rs
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@@ -1,13 +1,14 @@
#![no_std] #![no_std]
#![no_main] #![no_main]
use core::ptr; use core::{arch::asm, ptr};
use panic_halt as _; // you can put a breakpoint on `rust_begin_unwind` to catch panics use panic_halt as _; // you can put a breakpoint on `rust_begin_unwind` to catch panics
use cortex_m_rt::entry; use cortex_m_rt::entry;
use driver_and_task_library::{ use driver_and_task_library::{
setup_board, Function, Pin, Port, PortOptions, ReadablePinOptions, WritablePinOptions, H, L, UsableBoard, setup_board, Function, Pin, Port, PortOptions, ReadablePinOptions, UsableBoard,
WritablePinOptions, H, L,
}; };
const SYSCTL_RCGC1_R: *mut u32 = 0x400FE104 as *mut u32; const SYSCTL_RCGC1_R: *mut u32 = 0x400FE104 as *mut u32;
@@ -43,20 +44,26 @@ const PINS_0_AND_1: u32 = 0b0000_0011;
fn uart0_init(board: UsableBoard) { fn uart0_init(board: UsableBoard) {
unsafe { unsafe {
// activate UART0 // activate UART0
ptr::write_volatile(SYSCTL_RCGC1_R, ptr::read_volatile(SYSCTL_RCGC1_R) | SYSCTL_RCGC1_UART0); ptr::write_volatile(
SYSCTL_RCGC1_R,
ptr::read_volatile(SYSCTL_RCGC1_R) | SYSCTL_RCGC1_UART0,
);
// activate port A // activate port A
// ptr::write_volatile(SYSCTL_RCGC2_R, ptr::read_volatile(SYSCTL_RCGC2_R) | SYSCTL_RCGC2_GPIOA); // ptr::write_volatile(SYSCTL_RCGC2_R, ptr::read_volatile(SYSCTL_RCGC2_R) | SYSCTL_RCGC2_GPIOA);
// ^ commented in favor of v // ^ commented in favor of v
board.setup_gpio_port(Port::A, PortOptions); board.setup_gpio_port(Port::A, PortOptions);
// disable UART while setting it up // disable UART while setting it up
ptr::write_volatile(UART0_CTL_R, ptr::read_volatile(UART0_CTL_R) & !UART_CTL_UARTEN); ptr::write_volatile(
UART0_CTL_R,
ptr::read_volatile(UART0_CTL_R) & !UART_CTL_UARTEN,
);
// ignore: // IBRD = int(50,000,000 / (16 * 115,200)) = int(27.1267) // ignore: // IBRD = int(50,000,000 / (16 * 115,200)) = int(27.1267)
// IBRD = int(16,000,000 / (16 * 115,200)) = int(8.680) // 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);
ptr::write_volatile(UART0_IBRD_R, 8); ptr::write_volatile(UART0_IBRD_R, 8);
// ignore: // FBRD = int(0.1267 * 64 + 0.5) = 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 // 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);
@@ -65,25 +72,32 @@ fn uart0_init(board: UsableBoard) {
// 8 bit word length (no parity bits, one stop bit, FIFOs) // 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);
// 8 bit word length (no parity bits, one stop bit, no FIFOs) // 8 bit word length (no parity bits, one stop bit, no 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 // enable UART since it's been set up
ptr::write_volatile(UART0_CTL_R, ptr::read_volatile(UART0_CTL_R) | UART_CTL_UARTEN); ptr::write_volatile(
UART0_CTL_R,
ptr::read_volatile(UART0_CTL_R) | UART_CTL_UARTEN,
);
// enable alt funct on PA1-0 // enable alt funct on PA1-0
ptr::write_volatile(GPIO_PORTA_AFSEL_R, ptr::read_volatile(GPIO_PORTA_AFSEL_R) | PINS_0_AND_1); 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 // 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); ptr::write_volatile(
GPIO_PORTA_DEN_R,
ptr::read_volatile(GPIO_PORTA_AFSEL_R) | PINS_0_AND_1,
);
} }
} }
fn uart0_out_char(c: u8) { fn uart0_out_char(c: u8) {
loop { loop {
let fr = unsafe { let fr = unsafe { ptr::read_volatile(UART0_FR_R) };
ptr::read_volatile(UART0_FR_R)
};
if (fr & UART_FR_TXFF) == 0 { if (fr & UART_FR_TXFF) == 0 {
break; break;
} }
} }
@@ -134,27 +148,35 @@ fn main() -> ! {
rgb_led.write_all(cyan); rgb_led.write_all(cyan);
uart0_init(board); uart0_init(board);
rgb_led.write_all(white); rgb_led.write_all(white);
for _ in 0..2 { for _ in 0..2 {
for c in [
'H', 'a', 'y', '!', '\r', '\n', 'H', 'e', 'y', '!', '\r', '\n', 'H', 'e', 'y', '!',
for c in ['H', 'a', 'y', '!', '\n', 'H', 'e', 'y', '!', '\n', 'H', 'e', 'y', '!', '\n', 'H', 'e', 'y', '!', '\n', ] { '\r', '\n', 'H', 'e', 'y', '!', '\r', '\n',
] {
uart0_out_char(c as u8); uart0_out_char(c as u8);
} }
} }
uart0_out_string("Those example string!\n"); uart0_out_string("Those example string!\r\n");
loop { loop {
match switches.read_all() { match switches.read_all() {
[L, L] => rgb_led.write_all(white), [L, L] => {
rgb_led.write_all(white);
uart0_out_string("Hey! You're pressing the button down!\r\n");
}
[L, H] => rgb_led.write_all(blue), [L, H] => rgb_led.write_all(blue),
[H, L] => rgb_led.write_all(red), [H, L] => rgb_led.write_all(red),
[H, H] => rgb_led.write_all(green), [H, H] => rgb_led.write_all(green),
} }
for _ in 0..1000000 {
unsafe {
asm!("nop");
}
}
} }
} }