added pio-based rotary encoder reading.

Cargo.toml

@@ -7,7 +7,10 @@ license = "MIT OR Apache-2.0"
 [dependencies]
 cortex-m = {version = "0.7"}
 cortex-m-rt = "0.7"
+cortex-m-rtic = "1.1.4"
 embedded-hal = { version = "0.2.5", features = ["unproven"] }
+embedded-alloc = "0.5.1"
+rp2040-monotonic = "1.3.0"
 
 defmt = "0.3"
 defmt-rtt = "0.4"
@@ -17,7 +20,8 @@ panic-probe = { version = "0.3", features = ["print-defmt"] }
 rp-pico = "0.8"
 max31855 = "0.1.0"
 hd44780-driver = "0.4.0"
-embedded-alloc = "0.5.1"
+pio-proc = "0.2"
+pio = "0.2"
 
 # cargo build/run
 [profile.dev]

src/encoder.pio

@@ -0,0 +1,51 @@
+; from https://github.com/GitJer/Rotary_encoder/blob/master/pio_rotary_encoder.pio
+.program pio_rotary_encoder
+.wrap_target
+.origin 0        ; The jump table has to start at 0
+                 ; it contains the correct jumps for each of the 16
+                 ; combination of 4 bits formed by A'B'AB
+                 ; A = current reading of pin_A of the rotary encoder
+                 ; A' = previous reading of pin_A of the rotary encoder
+                 ; B = current reading of pin_B of the rotary encoder
+                 ; B' = previous reading of pin_B of the rotary encoder
+    jmp read     ; 0000 = from 00 to 00 = no change in reading
+    jmp CW       ; 0001 = from 00 to 01 = clockwise rotation
+    jmp CCW      ; 0010 = from 00 to 10 = counter clockwise rotation
+    jmp read     ; 0011 = from 00 to 11 = error
+
+    jmp CCW      ; 0100 = from 01 to 00 = counter clockwise rotation
+    jmp read     ; 0101 = from 01 to 01 = no change in reading
+    jmp read     ; 0110 = from 01 to 10 = error
+    jmp CW       ; 0111 = from 01 to 11 = clockwise rotation
+
+    jmp CW       ; 1000 = from 10 to 00 = clockwise rotation
+    jmp read     ; 1001 = from 10 to 01 = error
+    jmp read     ; 1010 = from 10 to 10 = no change in reading
+    jmp CCW      ; 1011 = from 10 to 11 = counter clockwise rotation
+
+    jmp read     ; 1100 = from 11 to 00 = error
+    jmp CCW      ; 1101 = from 11 to 01 = counter clockwise rotation
+    jmp CW       ; 1110 = from 11 to 10 = clockwise rotation
+    jmp read     ; 1111 = from 11 to 11 = no change in reading
+
+pc_start:        ; this is the entry point for the program
+    in pins 2    ; read the current values of A and B and use
+                 ; them to initialize the previous values (A'B')
+read:
+    mov osr isr  ; the OSR is (after the next instruction) used to shift
+                 ; the two bits with the previous values into the ISR
+    out isr 2    ; shift the previous value into the ISR. This also sets
+                 ; all other bits in the ISR to 0
+    in pins 2    ; shift the current value into the ISR
+                 ; the 16 LSB of the ISR now contain 000000000000A'B'AB
+                 ; this represents a jmp instruction to the address A'B'AB
+    mov exec isr ; do the jmp encoded in the ISR
+CW:              ; a clockwise rotation was detected
+    irq 0        ; signal a clockwise rotation via an IRQ
+    jmp read     ; jump to reading the current values of A and B
+CCW:             ; a counter clockwise rotation was detected
+    irq 1        ; signal a counter clockwise rotation via an IRQ
+;    jmp read    ; jump to reading the current values of A and B.
+                 ; the jmp isn't needed because of the .wrap, and the first
+                 ; statement of the program happens to be a jmp read
+.wrap

src/main.rs

@@ -1,34 +1,43 @@
 #![no_std]
 #![no_main]
 
+#[rtic::app(
+    device = rp_pico::hal::pac,
+    dispatchers = [TIMER_IRQ_1, TIMER_IRQ_2, TIMER_IRQ_3]
+    )]
+mod app {
     extern crate alloc;
     use alloc::format;
-use bsp::{
-    entry,
-    hal::{
-        gpio,
-        uart::{UartConfig, UartPeripheral},
-    },
-};
     use core::fmt::Write;
     use cortex_m::delay::Delay;
     use defmt_rtt as _;
     use embedded_alloc::Heap;
-use embedded_hal::digital::v2::OutputPin;
+    use embedded_hal::{digital::v2::ToggleableOutputPin, spi::MODE_0};
-use embedded_hal::spi::MODE_0;
+    use hd44780::{bus::FourBitBus, HD44780};
     use panic_probe as _;
 
-// Provide an alias for our BSP so we can switch targets quickly.
+    use rp2040_monotonic::{fugit::Duration, Rp2040Monotonic};
-// Uncomment the BSP you included in Cargo.toml, the rest of the code does not need to change.
-use rp_pico as bsp;
 
-use bsp::hal::{
+    use rp_pico::{
+        hal::{
             clocks::{init_clocks_and_plls, Clock},
             fugit::RateExtU32,
-    pac,
+            gpio::{
+                self,
+                bank0::{
+                    Gpio0, Gpio1, Gpio14, Gpio16, Gpio17, Gpio18, Gpio19, Gpio2, Gpio20, Gpio21,
+                    Gpio25, Gpio3, Gpio4, Gpio5,
+                },
+                FunctionPio0, FunctionSio, FunctionSpi, FunctionUart, Pin, PullDown, SioOutput,
+            },
+            pio::PIOExt,
             sio::Sio,
-    spi::Spi,
+            spi::{self, Spi},
+            uart::{self, UartConfig, UartPeripheral},
             watchdog::Watchdog,
+        },
+        pac::{self, SPI0, UART0},
+        Pins,
     };
 
     use hd44780_driver as hd44780;
@@ -37,32 +46,92 @@ use max31855::{Max31855, Unit};
     #[global_allocator]
     static HEAP: Heap = Heap::empty();
 
-fn write_lcd<T: hd44780_driver::bus::DataBus>(
+    const MONO_NUM: u32 = 1;
-    lcd: &mut hd44780::HD44780<T>,
+    const MONO_DENOM: u32 = 1_000_000;
-    delay: &mut Delay,
+    const ONE_SEC_TICKS: u64 = 1_000_000;
-    string: &str,
+
-) {
+    type Uart = UartPeripheral<
-    lcd.reset(delay).unwrap();
+        uart::Enabled,
-    lcd.clear(delay).unwrap();
+        UART0,
-    lcd.write_str(string, delay).unwrap();
+        (
+            Pin<Gpio0, FunctionUart, PullDown>,
+            Pin<Gpio1, FunctionUart, PullDown>,
+        ),
+    >;
+
+    type Led = Pin<Gpio25, FunctionSio<SioOutput>, PullDown>;
+
+    type ExternalLed = Pin<Gpio14, FunctionSio<SioOutput>, PullDown>;
+
+    type ThermocoupleSpi = Spi<
+        spi::Enabled,
+        SPI0,
+        (
+            Pin<Gpio3, FunctionSpi, PullDown>,
+            Pin<Gpio4, FunctionSpi, PullDown>,
+            Pin<Gpio2, FunctionSpi, PullDown>,
+        ),
+    >;
+
+    type Lcd = HD44780<
+        FourBitBus<
+            Pin<Gpio16, FunctionSio<SioOutput>, PullDown>,
+            Pin<Gpio17, FunctionSio<SioOutput>, PullDown>,
+            Pin<Gpio18, FunctionSio<SioOutput>, PullDown>,
+            Pin<Gpio19, FunctionSio<SioOutput>, PullDown>,
+            Pin<Gpio20, FunctionSio<SioOutput>, PullDown>,
+            Pin<Gpio21, FunctionSio<SioOutput>, PullDown>,
+        >,
+    >;
+
+    #[monotonic(binds = TIMER_IRQ_0, default = true)]
+    type Rp2040Mono = Rp2040Monotonic;
+
+    pub struct Thermocouple {
+        cs: Pin<Gpio5, FunctionSio<SioOutput>, PullDown>,
+        spi: ThermocoupleSpi,
     }
 
-#[entry]
+    impl Thermocouple {
-fn main() -> ! {
+        fn read_temp(
+            &mut self,
+        ) -> Result<f32, max31855::Error<core::convert::Infallible, core::convert::Infallible>>
+        {
+            self.spi.read_thermocouple(&mut self.cs, Unit::Celsius)
+        }
+    }
+
+    #[shared]
+    struct Shared {
+        delay: Delay,
+        recent_temp: f32,
+        target_temp: f32,
+        uart: Uart,
+    }
+
+    #[local]
+    struct Local {
+        led: Led,
+        thermocouple: Thermocouple,
+        lcd: Lcd,
+        external_led: ExternalLed,
+    }
+
+    #[init]
+    fn init(mut ctx: init::Context) -> (Shared, Local, init::Monotonics) {
+        let mut watchdog = Watchdog::new(ctx.device.WATCHDOG);
         let mut pac = pac::Peripherals::take().unwrap();
-    let core = pac::CorePeripherals::take().unwrap();
+        let sio = Sio::new(ctx.device.SIO);
-    let mut watchdog = Watchdog::new(pac.WATCHDOG);
-    let sio = Sio::new(pac.SIO);
 
         // External high-speed crystal on the pico board is 12Mhz
         let external_xtal_freq_hz = 12_000_000u32;
         let clocks = init_clocks_and_plls(
             external_xtal_freq_hz,
-        pac.XOSC,
+            ctx.device.XOSC,
-        pac.CLOCKS,
+            ctx.device.CLOCKS,
-        pac.PLL_SYS,
+            ctx.device.PLL_SYS,
-        pac.PLL_USB,
+            ctx.device.PLL_USB,
-        &mut pac.RESETS,
+            &mut ctx.device.RESETS,
             &mut watchdog,
         )
         .ok()
@@ -76,23 +145,27 @@ fn main() -> ! {
             unsafe { HEAP.init(HEAP_MEM.as_ptr() as usize, HEAP_SIZE) }
         }
 
-    let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz());
+        let mut delay =
+            cortex_m::delay::Delay::new(ctx.core.SYST, clocks.system_clock.freq().to_Hz());
 
-    let pins = bsp::Pins::new(
+        let pins = Pins::new(
-        pac.IO_BANK0,
+            ctx.device.IO_BANK0,
-        pac.PADS_BANK0,
+            ctx.device.PADS_BANK0,
             sio.gpio_bank0,
-        &mut pac.RESETS,
+            &mut ctx.device.RESETS,
         );
 
-    let uart_pins = (pins.gpio0.into_function(), pins.gpio1.into_function());
+        let mut uart: Uart = UartPeripheral::new(
-    let mut uart = UartPeripheral::new(pac.UART0, uart_pins, &mut pac.RESETS)
+            ctx.device.UART0,
+            (pins.gpio0.into_function(), pins.gpio1.into_function()),
+            &mut ctx.device.RESETS,
+        )
         .enable(
             UartConfig::new(
                 9600u32.Hz(),
-                bsp::hal::uart::DataBits::Eight,
+                rp_pico::hal::uart::DataBits::Eight,
                 None,
-                bsp::hal::uart::StopBits::One,
+                rp_pico::hal::uart::StopBits::One,
             ),
             clocks.peripheral_clock.freq(),
         )
@@ -101,29 +174,36 @@ fn main() -> ! {
         defmt::info!("Program start");
         writeln!(uart, "Program start\r",).unwrap();
 
-    let mut led_pin = pins.led.into_push_pull_output();
+        let led_pin: Led = pins.led.into_push_pull_output();
-    let mut external_led_pin = pins.gpio14.into_push_pull_output();
+        let external_led_pin: ExternalLed = pins.gpio14.into_push_pull_output();
-    //clk
-    let thermometer_spi_sck = pins.gpio2.into_function::<gpio::FunctionSpi>();
-    //MOSI, I think unused?
-    let thermometer_spi_tx = pins.gpio3.into_function::<gpio::FunctionSpi>();
-    //do, or MISO.
-    let thermometer_spi_rx = pins.gpio4.into_function::<gpio::FunctionSpi>();
-    //cs
-    let mut thermometer_spi_csn = pins
-        .gpio5
-        .into_push_pull_output_in_state(gpio::PinState::Low);
 
-    let thermometer_spi_device = pac.SPI0;
+        //cs
-    let spi_pin_layout = (thermometer_spi_tx, thermometer_spi_rx, thermometer_spi_sck);
+        let thermometer_spi_device = ctx.device.SPI0;
-    let mut spi = Spi::<_, _, _, 8>::new(thermometer_spi_device, spi_pin_layout).init(
+        let thermocouple = Thermocouple {
-        &mut pac.RESETS,
+            cs: pins
+                .gpio5
+                .into_push_pull_output_in_state(gpio::PinState::Low),
+
+            spi: Spi::<_, _, _, 8>::new(
+                thermometer_spi_device,
+                (
+                    //mosi
+                    pins.gpio3.into_function::<gpio::FunctionSpi>(),
+                    //miso/do
+                    pins.gpio4.into_function::<gpio::FunctionSpi>(),
+                    //clk
+                    pins.gpio2.into_function::<gpio::FunctionSpi>(),
+                ),
+            )
+            .init(
+                &mut ctx.device.RESETS,
                 125_000_000u32.Hz(),
                 4u32.MHz(),
                 MODE_0,
-    );
+            ),
+        };
 
-    let mut lcd = hd44780::HD44780::new_4bit(
+        let lcd: Lcd = hd44780::HD44780::new_4bit(
             pins.gpio16.into_push_pull_output(), //rs
             pins.gpio17.into_push_pull_output(), //enable
             pins.gpio18.into_push_pull_output(), //d4
@@ -134,20 +214,117 @@ fn main() -> ! {
         )
         .unwrap();
 
-    write_lcd(&mut lcd, &mut delay, "Starting");
+        let rotary_clk: Pin<_, FunctionPio0, _> = pins.gpio11.into_function();
-    loop {
+        let rotary_clk_id = rotary_clk.id().num;
-        led_pin.set_high().unwrap();
+        let rotary_dt: Pin<_, FunctionPio0, _> = pins.gpio12.into_function();
-        external_led_pin.set_low().unwrap();
+        let rotary_dt_id = rotary_dt.id().num;
-        delay.delay_ms(500);
+        let program = pio_proc::pio_file!("src/encoder.pio");
-        led_pin.set_low().unwrap();
+
-        external_led_pin.set_high().unwrap();
+        let (mut pio, sm0, _, _, _) = pac.PIO0.split(&mut pac.RESETS);
-        delay.delay_ms(500);
+        pio.irq0().enable_sm_interrupt(0);
-        match spi.read_thermocouple(&mut thermometer_spi_csn, Unit::Celsius) {
+        pio.irq1().enable_sm_interrupt(1);
+        let installed = pio.install(&program.program).unwrap();
+        let (mut sm, _, _) = rp_pico::hal::pio::PIOBuilder::from_program(installed)
+            .set_pins(rotary_clk_id, 2)
+            .build(sm0);
+        sm.set_pindirs([
+            (rotary_clk_id, rp_pico::hal::pio::PinDir::Output),
+            (rotary_dt_id, rp_pico::hal::pio::PinDir::Output),
+        ]);
+        sm.start();
+
+        let mono = Rp2040Mono::new(ctx.device.TIMER);
+
+        heartbeat::spawn().unwrap();
+        second_heartbeat::spawn().unwrap();
+
+        (
+            Shared {
+                delay,
+                recent_temp: 0.0,
+                target_temp: 25.0,
+                uart,
+            },
+            Local {
+                led: led_pin,
+                thermocouple,
+                lcd,
+                external_led: external_led_pin,
+            },
+            init::Monotonics(mono),
+        )
+    }
+
+    #[task(binds = PIO0_IRQ_0, shared = [target_temp])]
+    fn inc_target(mut ctx: inc_target::Context) {
+        ctx.shared.target_temp.lock(|t| {
+            *t += 1.0;
+        });
+        update_display::spawn().unwrap();
+    }
+
+    #[task(binds = PIO0_IRQ_1, shared = [target_temp])]
+    fn dec_target(mut ctx: dec_target::Context) {
+        ctx.shared.target_temp.lock(|t| {
+            *t -= 1.0;
+        });
+        update_display::spawn().unwrap();
+    }
+
+    #[task(local = [thermocouple], shared = [recent_temp, uart])]
+    fn read_temp(mut ctx: read_temp::Context) {
+        match ctx.local.thermocouple.read_temp() {
             Ok(v) => {
-                writeln!(uart, "Current: {} \r", v).unwrap();
+                ctx.shared
-                write_lcd(&mut lcd, &mut delay, &format!("{:02.2} C", v))
+                    .uart
+                    .lock(|u| writeln!(u, "{:02.2} C\r", v).unwrap());
+                ctx.shared.recent_temp.lock(|t| *t = v);
+                update_display::spawn().unwrap();
             }
             Err(e) => defmt::error!("error reading temp {}", defmt::Debug2Format(&e)),
-        };
+        }
+    }
+
+    #[task(local = [lcd], shared = [delay, recent_temp, target_temp])]
+    fn update_display(mut ctx: update_display::Context) {
+        ctx.shared.delay.lock(|d| {
+            ctx.local.lcd.reset(d).unwrap();
+            ctx.local.lcd.clear(d).unwrap();
+            ctx.shared.recent_temp.lock(|t| {
+                ctx.local
+                    .lcd
+                    .write_str(&format!("{:02.2} C", t), d)
+                    .unwrap();
+            });
+            ctx.local.lcd.set_cursor_pos(40, d).unwrap();
+            ctx.shared.target_temp.lock(|t| {
+                ctx.local
+                    .lcd
+                    .write_str(&format!("Target: {:02.2} C", t), d)
+                    .unwrap()
+            })
+        });
+    }
+
+    #[task(local = [led])]
+    fn heartbeat(ctx: heartbeat::Context) {
+        // Flicker the built-in LED
+        ctx.local.led.toggle().unwrap();
+
+        // Re-spawn this task after 1 second
+        let one_second = Duration::<u64, MONO_NUM, MONO_DENOM>::from_ticks(ONE_SEC_TICKS);
+        read_temp::spawn().unwrap();
+        heartbeat::spawn_after(one_second).unwrap();
+    }
+
+    #[task(local = [external_led])]
+    fn second_heartbeat(ctx: second_heartbeat::Context) {
+        // Flicker the built-in LED
+        ctx.local.external_led.toggle().unwrap();
+
+        // Re-spawn this task after 1 second
+        let one_and_one_half_second =
+            Duration::<u64, MONO_NUM, MONO_DENOM>::from_ticks((ONE_SEC_TICKS as f64 * 1.14) as u64);
+        second_heartbeat::spawn_after(one_and_one_half_second).unwrap();
     }
 }