Tx and Rx setup
This commit is contained in:
Michael van Niekerk
262
examples/rp/src/bin/pio_uart.rs
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262
examples/rp/src/bin/pio_uart.rs
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//! This example shows how to use USB (Universal Serial Bus) in the RP2040 chip.
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//!
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//! This creates a USB serial port that echos.
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#![no_std]
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#![no_main]
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#![feature(type_alias_impl_trait)]
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use defmt::{info, panic};
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use embassy_executor::Spawner;
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use embassy_futures::join::join;
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use embassy_rp::bind_interrupts;
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use embassy_rp::peripherals::{PIO0, USB};
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use embassy_rp::usb::{Driver, Instance, InterruptHandler};
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use embassy_usb::class::cdc_acm::{CdcAcmClass, State};
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use embassy_usb::driver::EndpointError;
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use embassy_usb::{Builder, Config};
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use embassy_rp::pio::{InterruptHandler as PioInterruptHandler};
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use {defmt_rtt as _, panic_probe as _};
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bind_interrupts!(struct UsbIrqs {
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USBCTRL_IRQ => InterruptHandler<USB>;
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});
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bind_interrupts!(struct PioIrqs {
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PIO0_IRQ_0 => PioInterruptHandler<PIO0>;
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});
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#[embassy_executor::main]
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async fn main(_spawner: Spawner) {
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info!("Hello there!");
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let p = embassy_rp::init(Default::default());
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// Create the driver, from the HAL.
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let driver = Driver::new(p.USB, UsbIrqs);
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// Create embassy-usb Config
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let mut config = Config::new(0xc0de, 0xcafe);
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config.manufacturer = Some("Embassy");
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config.product = Some("PIO UART example");
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config.serial_number = Some("12345678");
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config.max_power = 100;
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config.max_packet_size_0 = 64;
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// Required for windows compatibility.
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// https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/kconfig/CONFIG_CDC_ACM_IAD.html#help
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config.device_class = 0xEF;
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config.device_sub_class = 0x02;
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config.device_protocol = 0x01;
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config.composite_with_iads = true;
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// Create embassy-usb DeviceBuilder using the driver and config.
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// It needs some buffers for building the descriptors.
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let mut device_descriptor = [0; 256];
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let mut config_descriptor = [0; 256];
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let mut bos_descriptor = [0; 256];
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let mut control_buf = [0; 64];
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let mut state = State::new();
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let mut builder = Builder::new(
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driver,
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config,
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&mut device_descriptor,
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&mut config_descriptor,
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&mut bos_descriptor,
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&mut control_buf,
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);
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// Create classes on the builder.
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let mut class = CdcAcmClass::new(&mut builder, &mut state, 64);
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// Build the builder.
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let mut usb = builder.build();
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// Run the USB device.
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let usb_fut = usb.run();
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// Do stuff with the class!
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let echo_fut = async {
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loop {
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class.wait_connection().await;
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info!("Connected");
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let _ = echo(&mut class).await;
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info!("Disconnected");
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}
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};
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// Run everything concurrently.
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// If we had made everything `'static` above instead, we could do this using separate tasks instead.
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join(usb_fut, echo_fut).await;
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}
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struct Disconnected {}
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impl From<EndpointError> for Disconnected {
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fn from(val: EndpointError) -> Self {
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match val {
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EndpointError::BufferOverflow => panic!("Buffer overflow"),
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EndpointError::Disabled => Disconnected {},
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}
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}
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}
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async fn echo<'d, T: Instance + 'd>(class: &mut CdcAcmClass<'d, Driver<'d, T>>) -> Result<(), Disconnected> {
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let mut buf = [0; 64];
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loop {
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let n = class.read_packet(&mut buf).await?;
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let data = &buf[..n];
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info!("data: {:x}", data);
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class.write_packet(data).await?;
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}
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}
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mod uart {
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use embassy_rp::peripherals::PIO0;
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use embassy_rp::pio::{Common, Pio, PioPin, StateMachine};
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use embassy_rp::Peripheral;
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use crate::PioIrqs;
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pub struct PioUart<'a> {
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baud: u64,
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pio: Common<'a, PIO0>,
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sm0: StateMachine<'a, PIO0, 0>,
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sm1: StateMachine<'a, PIO0, 1>,
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}
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impl<'a> PioUart<'a> {
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pub async fn new(
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baud: u64,
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pio: impl Peripheral<P = PIO0> + 'a,
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tx_pin: impl PioPin,
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rx_pin: impl PioPin,
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) -> PioUart<'a> {
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let Pio {
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mut common,
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mut sm0,
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mut sm1,
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..
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} = Pio::new(pio, PioIrqs);
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crate::uart_tx::setup_uart_tx_on_sm0(&mut common, &mut sm0, tx_pin, baud);
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crate::uart_rx::setup_uart_rx_on_sm1(&mut common, &mut sm1, rx_pin, baud);
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PioUart {
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baud,
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pio: common,
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sm0,
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sm1,
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}
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}
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}
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}
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mod uart_tx {
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use embassy_rp::gpio::Level;
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use embassy_rp::peripherals::PIO0;
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use embassy_rp::pio::{Common, Config, Direction, FifoJoin, PioPin, ShiftDirection, StateMachine};
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use embassy_rp::relocate::RelocatedProgram;
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use fixed::traits::ToFixed;
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use fixed_macro::types::U56F8;
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pub fn setup_uart_tx_on_sm0<'a>(
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common: &mut Common<'a, PIO0>,
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sm_tx: &mut StateMachine<'a, PIO0, 0>,
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tx_pin: impl PioPin,
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baud: u64,
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) {
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let prg = pio_proc::pio_asm!(
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r#"
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;.program uart_tx
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.side_set 1 opt
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; An 8n1 UART transmit program.
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; OUT pin 0 and side-set pin 0 are both mapped to UART TX pin.
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pull side 1 [7] ; Assert stop bit, or stall with line in idle state
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set x, 7 side 0 [7] ; Preload bit counter, assert start bit for 8 clocks
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bitloop: ; This loop will run 8 times (8n1 UART)
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out pins, 1 ; Shift 1 bit from OSR to the first OUT pin
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jmp x-- bitloop [6] ; Each loop iteration is 8 cycles.
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"#
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);
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let tx_pin = common.make_pio_pin(tx_pin);
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sm_tx.set_pins(Level::High, &[&tx_pin]);
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sm_tx.set_pin_dirs(Direction::Out, &[&tx_pin]);
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let relocated = RelocatedProgram::new(&prg.program);
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let mut cfg = Config::default();
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cfg.use_program(&common.load_program(&relocated), &[&tx_pin]);
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cfg.clock_divider = (U56F8!(125_000_000) / (8 * baud)).to_fixed();
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cfg.shift_out.auto_fill = false;
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cfg.shift_out.direction = ShiftDirection::Right;
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cfg.fifo_join = FifoJoin::TxOnly;
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cfg.set_out_pins(&[&tx_pin]);
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cfg.set_set_pins(&[&tx_pin]);
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sm_tx.set_config(&cfg);
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sm_tx.set_enable(true)
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}
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}
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mod uart_rx {
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use embassy_rp::gpio::Level;
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use embassy_rp::peripherals::PIO0;
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use embassy_rp::pio::{Common, Config, Direction, FifoJoin, PioPin, ShiftDirection, StateMachine};
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use embassy_rp::relocate::RelocatedProgram;
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use fixed::traits::ToFixed;
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use fixed_macro::types::U56F8;
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pub fn setup_uart_rx_on_sm1<'a>(
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common: &mut Common<'a, PIO0>,
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sm_rx: &mut StateMachine<'a, PIO0, 1>,
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rx_pin: impl PioPin,
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baud: u64,
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) {
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let prg = pio_proc::pio_asm!(
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r#"
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;.program uart_rx
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; Slightly more fleshed-out 8n1 UART receiver which handles framing errors and
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; break conditions more gracefully.
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; IN pin 0 and JMP pin are both mapped to the GPIO used as UART RX.
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start:
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wait 0 pin 0 ; Stall until start bit is asserted
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set x, 7 [10] ; Preload bit counter, then delay until halfway through
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bitloop: ; the first data bit (12 cycles incl wait, set).
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in pins, 1 ; Shift data bit into ISR
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jmp x-- bitloop [6] ; Loop 8 times, each loop iteration is 8 cycles
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jmp pin good_stop ; Check stop bit (should be high)
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irq 4 rel ; Either a framing error or a break. Set a sticky flag,
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wait 1 pin 0 ; and wait for line to return to idle state.
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jmp start ; Don't push data if we didn't see good framing.
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good_stop: ; No delay before returning to start; a little slack is
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push ; important in case the TX clock is slightly too fast.
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"#
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);
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let rx_pin = common.make_pio_pin(rx_pin);
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sm_rx.set_pins(Level::High, &[&rx_pin]);
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sm_rx.set_pin_dirs(Direction::In, &[&rx_pin]);
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let relocated = RelocatedProgram::new(&prg.program);
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let mut cfg = Config::default();
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cfg.use_program(&common.load_program(&relocated), &[&rx_pin]);
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cfg.clock_divider = (U56F8!(125_000_000) / (8 * baud)).to_fixed();
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cfg.shift_out.auto_fill = false;
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cfg.shift_out.direction = ShiftDirection::Right;
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cfg.fifo_join = FifoJoin::RxOnly;
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cfg.set_in_pins(&[&rx_pin]);
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cfg.set_jmp_pin(&rx_pin);
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// cfg.set_set_pins(&[&rx_pin]);
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sm_rx.set_config(&cfg);
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sm_rx.set_enable(true)
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}
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}
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