feat: add basic support for nRF51 chips to embassy-nrf

embassy-nrf/Cargo.toml

@@ -15,6 +15,7 @@ src_base_git = "https://github.com/embassy-rs/embassy/blob/$COMMIT/embassy-nrf/s
 
 features = ["time", "defmt", "unstable-pac", "gpiote", "time-driver-rtc1"]
 flavors = [
+    { regex_feature = "nrf51", target = "thumbv6m-none-eabi" },
     { regex_feature = "nrf52.*", target = "thumbv7em-none-eabihf" },
     { regex_feature = "nrf53.*", target = "thumbv8m.main-none-eabihf" },
     { regex_feature = "nrf91.*", target = "thumbv8m.main-none-eabihf" },
@@ -28,6 +29,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 default = ["rt"]
 ## Cortex-M runtime (enabled by default)
 rt = [
+    "nrf51-pac?/rt",
     "nrf52805-pac?/rt",
     "nrf52810-pac?/rt",
     "nrf52811-pac?/rt",
@@ -71,6 +73,8 @@ reset-pin-as-gpio = []
 qspi-multiwrite-flash = []
 
 #! ### Chip selection features
+## nRF51
+nrf51 = ["nrf51-pac", "_nrf51", "portable-atomic/unsafe-assume-single-core"]
 ## nRF52805
 nrf52805 = ["nrf52805-pac", "_nrf52"]
 ## nRF52810
@@ -104,6 +108,7 @@ _nrf5340-net = ["_nrf5340", "nrf5340-net-pac"]
 _nrf5340 = ["_gpio-p1", "_dppi"]
 _nrf9160 = ["nrf9160-pac", "_dppi"]
 _nrf52 = ["_ppi"]
+_nrf51 = ["_ppi"]
 
 _time-driver = ["dep:embassy-time-driver", "embassy-time-driver?/tick-hz-32_768"]
 
@@ -132,6 +137,8 @@ embedded-hal-async = { version = "1.0" }
 embedded-io = { version = "0.6.0" }
 embedded-io-async = { version = "0.6.1" }
 
+portable-atomic = { version = "1", default-features = false, features = ["require-cas"] }
+
 defmt = { version = "0.3", optional = true }
 log = { version = "0.4.14", optional = true }
 cortex-m-rt = ">=0.6.15,<0.8"
@@ -144,6 +151,7 @@ embedded-storage-async = "0.4.0"
 cfg-if = "1.0.0"
 document-features = "0.2.7"
 
+nrf51-pac = { version = "0.12.0", optional = true }
 nrf52805-pac = { version = "0.12.0", optional = true }
 nrf52810-pac = { version = "0.12.0", optional = true }
 nrf52811-pac = { version = "0.12.0", optional = true }

embassy-nrf/src/chips/nrf51.rs

@@ -0,0 +1,168 @@
+pub use nrf51_pac as pac;
+
+/// The maximum buffer size that the EasyDMA can send/recv in one operation.
+pub const EASY_DMA_SIZE: usize = (1 << 14) - 1;
+pub const FORCE_COPY_BUFFER_SIZE: usize = 256;
+
+pub const FLASH_SIZE: usize = 128 * 1024;
+
+embassy_hal_internal::peripherals! {
+    // RTC
+    RTC0,
+    RTC1,
+
+    // WDT
+    WDT,
+
+    // NVMC
+    NVMC,
+
+    // RNG
+    RNG,
+
+    // UARTE
+    UART0,
+
+    // SPI/TWI
+    TWI0,
+    SPI0,
+
+    // ADC
+    ADC,
+
+    // TIMER
+    TIMER0,
+    TIMER1,
+    TIMER2,
+
+    // GPIOTE
+    GPIOTE_CH0,
+    GPIOTE_CH1,
+    GPIOTE_CH2,
+    GPIOTE_CH3,
+
+    // PPI
+    PPI_CH0,
+    PPI_CH1,
+    PPI_CH2,
+    PPI_CH3,
+    PPI_CH4,
+    PPI_CH5,
+    PPI_CH6,
+    PPI_CH7,
+    PPI_CH8,
+    PPI_CH9,
+    PPI_CH10,
+    PPI_CH11,
+    PPI_CH12,
+    PPI_CH13,
+    PPI_CH14,
+    PPI_CH15,
+
+    PPI_GROUP0,
+    PPI_GROUP1,
+    PPI_GROUP2,
+    PPI_GROUP3,
+
+    // GPIO port 0
+    P0_00,
+    P0_01,
+    P0_02,
+    P0_03,
+    P0_04,
+    P0_05,
+    P0_06,
+    P0_07,
+    P0_08,
+    P0_09,
+    P0_10,
+    P0_11,
+    P0_12,
+    P0_13,
+    P0_14,
+    P0_15,
+    P0_16,
+    P0_17,
+    P0_18,
+    P0_19,
+    P0_20,
+    P0_21,
+    P0_22,
+    P0_23,
+    P0_24,
+    P0_25,
+    P0_26,
+    P0_27,
+    P0_28,
+    P0_29,
+    P0_30,
+    P0_31,
+
+    // TEMP
+    TEMP,
+}
+
+// impl_timer!(TIMER0, TIMER0, TIMER0);
+// impl_timer!(TIMER1, TIMER1, TIMER1);
+// impl_timer!(TIMER2, TIMER2, TIMER2);
+
+impl_pin!(P0_00, 0, 0);
+impl_pin!(P0_01, 0, 1);
+impl_pin!(P0_02, 0, 2);
+impl_pin!(P0_03, 0, 3);
+impl_pin!(P0_04, 0, 4);
+impl_pin!(P0_05, 0, 5);
+impl_pin!(P0_06, 0, 6);
+impl_pin!(P0_07, 0, 7);
+impl_pin!(P0_08, 0, 8);
+impl_pin!(P0_09, 0, 9);
+impl_pin!(P0_10, 0, 10);
+impl_pin!(P0_11, 0, 11);
+impl_pin!(P0_12, 0, 12);
+impl_pin!(P0_13, 0, 13);
+impl_pin!(P0_14, 0, 14);
+impl_pin!(P0_15, 0, 15);
+impl_pin!(P0_16, 0, 16);
+impl_pin!(P0_17, 0, 17);
+impl_pin!(P0_18, 0, 18);
+impl_pin!(P0_19, 0, 19);
+impl_pin!(P0_20, 0, 20);
+impl_pin!(P0_21, 0, 21);
+impl_pin!(P0_22, 0, 22);
+impl_pin!(P0_23, 0, 23);
+impl_pin!(P0_24, 0, 24);
+impl_pin!(P0_25, 0, 25);
+impl_pin!(P0_26, 0, 26);
+impl_pin!(P0_27, 0, 27);
+impl_pin!(P0_28, 0, 28);
+impl_pin!(P0_29, 0, 29);
+impl_pin!(P0_30, 0, 30);
+impl_pin!(P0_31, 0, 31);
+
+embassy_hal_internal::interrupt_mod!(
+    POWER_CLOCK,
+    RADIO,
+    UART0,
+    SPI0_TWI0,
+    SPI1_TWI1,
+    GPIOTE,
+    ADC,
+    TIMER0,
+    TIMER1,
+    TIMER2,
+    RTC0,
+    TEMP,
+    RNG,
+    ECB,
+    CCM_AAR,
+    WDT,
+    RTC1,
+    QDEC,
+    LPCOMP,
+    SWI0,
+    SWI1,
+    SWI2,
+    SWI3,
+    SWI4,
+    SWI5,
+);

embassy-nrf/src/gpio.rs

@@ -8,8 +8,17 @@ use cfg_if::cfg_if;
 use embassy_hal_internal::{impl_peripheral, into_ref, PeripheralRef};
 
 use self::sealed::Pin as _;
+
+#[cfg(not(feature = "nrf51"))]
 use crate::pac::p0 as gpio;
+#[cfg(not(feature = "nrf51"))]
 use crate::pac::p0::pin_cnf::{DRIVE_A, PULL_A};
+
+#[cfg(feature = "nrf51")]
+use crate::pac::gpio;
+#[cfg(feature = "nrf51")]
+use crate::pac::gpio::pin_cnf::{DRIVE_A, PULL_A};
+
 use crate::{pac, Peripheral};
 
 /// A GPIO port with up to 32 pins.
@@ -376,6 +385,9 @@ pub(crate) mod sealed {
         fn block(&self) -> &gpio::RegisterBlock {
             unsafe {
                 match self.pin_port() / 32 {
+                    #[cfg(feature = "nrf51")]
+                    0 => &*pac::GPIO::ptr(),
+                    #[cfg(not(feature = "nrf51"))]
                     0 => &*pac::P0::ptr(),
                     #[cfg(feature = "_gpio-p1")]
                     1 => &*pac::P1::ptr(),

embassy-nrf/src/lib.rs

@@ -40,6 +40,7 @@ pub(crate) mod util;
 #[cfg(feature = "_time-driver")]
 mod time_driver;
 
+#[cfg(not(feature = "nrf51"))]
 pub mod buffered_uarte;
 pub mod gpio;
 #[cfg(feature = "gpiote")]
@@ -58,7 +59,12 @@ pub mod nvmc;
 ))]
 pub mod pdm;
 pub mod ppi;
-#[cfg(not(any(feature = "nrf52805", feature = "nrf52820", feature = "_nrf5340-net")))]
+#[cfg(not(any(
+    feature = "nrf51",
+    feature = "nrf52805",
+    feature = "nrf52820",
+    feature = "_nrf5340-net"
+)))]
 pub mod pwm;
 #[cfg(not(any(feature = "nrf51", feature = "_nrf9160", feature = "_nrf5340-net")))]
 pub mod qdec;
@@ -66,15 +72,20 @@ pub mod qdec;
 pub mod qspi;
 #[cfg(not(any(feature = "_nrf5340-app", feature = "_nrf9160")))]
 pub mod rng;
-#[cfg(not(any(feature = "nrf52820", feature = "_nrf5340-net")))]
+#[cfg(not(any(feature = "nrf51", feature = "nrf52820", feature = "_nrf5340-net")))]
 pub mod saadc;
+#[cfg(not(feature = "nrf51"))]
 pub mod spim;
+#[cfg(not(feature = "nrf51"))]
 pub mod spis;
 #[cfg(not(any(feature = "_nrf5340", feature = "_nrf9160")))]
 pub mod temp;
 pub mod timer;
+#[cfg(not(feature = "nrf51"))]
 pub mod twim;
+#[cfg(not(feature = "nrf51"))]
 pub mod twis;
+#[cfg(not(feature = "nrf51"))]
 pub mod uarte;
 #[cfg(any(
     feature = "_nrf5340-app",
@@ -87,6 +98,7 @@ pub mod usb;
 pub mod wdt;
 
 // This mod MUST go last, so that it sees all the `impl_foo!` macros
+#[cfg_attr(feature = "nrf51", path = "chips/nrf51.rs")]
 #[cfg_attr(feature = "nrf52805", path = "chips/nrf52805.rs")]
 #[cfg_attr(feature = "nrf52810", path = "chips/nrf52810.rs")]
 #[cfg_attr(feature = "nrf52811", path = "chips/nrf52811.rs")]
@@ -374,6 +386,7 @@ pub fn init(config: config::Config) -> Peripherals {
     let mut needs_reset = false;
 
     // Setup debug protection.
+    #[cfg(not(feature = "nrf51"))]
     match config.debug {
         config::Debug::Allowed => {
             #[cfg(feature = "_nrf52")]
@@ -489,7 +502,7 @@ pub fn init(config: config::Config) -> Peripherals {
     }
 
     // Configure LFCLK.
-    #[cfg(not(any(feature = "_nrf5340", feature = "_nrf9160")))]
+    #[cfg(not(any(feature = "nrf51", feature = "_nrf5340", feature = "_nrf9160")))]
     match config.lfclk_source {
         config::LfclkSource::InternalRC => r.lfclksrc.write(|w| w.src().rc()),
         config::LfclkSource::Synthesized => r.lfclksrc.write(|w| w.src().synth()),

embassy-nrf/src/ppi/ppi.rs

@@ -84,6 +84,7 @@ impl<'d, C: Channel, const EVENT_COUNT: usize, const TASK_COUNT: usize> Drop for
         let n = self.ch.number();
         r.ch[n].eep.write(|w| unsafe { w.bits(0) });
         r.ch[n].tep.write(|w| unsafe { w.bits(0) });
+        #[cfg(not(feature = "nrf51"))]
         r.fork[n].tep.write(|w| unsafe { w.bits(0) });
     }
 }

embassy-nrf/src/rng.rs

@@ -5,7 +5,7 @@
 use core::future::poll_fn;
 use core::marker::PhantomData;
 use core::ptr;
-use core::sync::atomic::{AtomicPtr, Ordering};
+use portable_atomic::{AtomicPtr, Ordering};
 use core::task::Poll;
 
 use embassy_hal_internal::drop::OnDrop;

embassy-nrf/src/time_driver.rs

@@ -1,6 +1,6 @@
 use core::cell::Cell;
-use core::sync::atomic::{compiler_fence, AtomicU32, AtomicU8, Ordering};
 use core::{mem, ptr};
+use portable_atomic::{compiler_fence, AtomicU32, AtomicU8, Ordering};
 
 use critical_section::CriticalSection;
 use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;

embassy-nrf/src/timer.rs

@@ -122,12 +122,16 @@ impl<'d, T: Instance> Timer<'d, T> {
         // since changing BITMODE while running can cause 'unpredictable behaviour' according to the specification.
         this.stop();
 
+        #[cfg(not(feature = "nrf51"))]
         if is_counter {
             regs.mode.write(|w| w.mode().low_power_counter());
         } else {
             regs.mode.write(|w| w.mode().timer());
         }
 
+        #[cfg(feature = "nrf51")]
+        regs.mode.write(|w| w.mode().timer());
+
         // Make the counter's max value as high as possible.
         // TODO: is there a reason someone would want to set this lower?
         regs.bitmode.write(|w| w.bitmode()._32bit());
@@ -238,7 +242,11 @@ pub struct Cc<'d, T: Instance> {
 impl<'d, T: Instance> Cc<'d, T> {
     /// Get the current value stored in the register.
     pub fn read(&self) -> u32 {
-        T::regs().cc[self.n].read().cc().bits()
+        #[cfg(not(feature = "nrf51"))]
+        return T::regs().cc[self.n].read().cc().bits();
+
+        #[cfg(feature = "nrf51")]
+        return T::regs().cc[self.n].read().bits();
     }
 
     /// Set the value stored in the register.
@@ -246,7 +254,11 @@ impl<'d, T: Instance> Cc<'d, T> {
     /// `event_compare` will fire when the timer's counter reaches this value.
     pub fn write(&self, value: u32) {
         // SAFETY: there are no invalid values for the CC register.
-        T::regs().cc[self.n].write(|w| unsafe { w.cc().bits(value) })
+        #[cfg(not(feature = "nrf51"))]
+        T::regs().cc[self.n].write(|w| unsafe { w.cc().bits(value) });
+
+        #[cfg(feature = "nrf51")]
+        T::regs().cc[self.n].write(|w| unsafe { w.bits(value) });
     }
 
     /// Capture the current value of the timer's counter in this register, and return it.

examples/nrf51/.cargo/config.toml

@@ -0,0 +1,9 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# replace nRF82840_xxAA with your chip as listed in `probe-rs chip list`
+runner = "probe-rs run --chip nRF51822_xxAA"
+
+[build]
+target = "thumbv6m-none-eabi"
+
+[env]
+DEFMT_LOG = "trace"

examples/nrf51/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+edition = "2021"
+name = "embassy-nrf51-examples"
+version = "0.1.0"
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+embassy-executor = { version = "0.5.0", path = "../../embassy-executor", features = ["task-arena-size-8192", "arch-cortex-m", "executor-thread", "executor-interrupt", "defmt", "integrated-timers"] }
+embassy-time = { version = "0.3.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime"] }
+embassy-nrf = { version = "0.1.0", path = "../../embassy-nrf", features = ["defmt", "nrf51", "time-driver-rtc1", "unstable-pac", "time", "rt"] }
+
+defmt = "0.3"
+defmt-rtt = "0.4"
+
+cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-single-core"] }
+cortex-m-rt = "0.7"
+panic-probe = { version = "0.3", features = ["print-defmt"] }
+
+[profile.release]
+debug = 2

examples/nrf51/build.rs

@@ -0,0 +1,35 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    // By default, Cargo will re-run a build script whenever
+    // any file in the project changes. By specifying `memory.x`
+    // here, we ensure the build script is only re-run when
+    // `memory.x` is changed.
+    println!("cargo:rerun-if-changed=memory.x");
+
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}

examples/nrf51/memory.x

@@ -0,0 +1,5 @@
+MEMORY
+{
+  FLASH                    : ORIGIN = 0x00000000, LENGTH = 256K
+  RAM                      : ORIGIN = 0x20000000, LENGTH = 32K
+}

examples/nrf51/src/bin/blinky.rs

@@ -0,0 +1,21 @@
+#![no_std]
+#![no_main]
+
+use embassy_executor::Spawner;
+use embassy_nrf::gpio::{Level, Output, OutputDrive};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+
+    let p = embassy_nrf::init(Default::default());
+    let mut led = Output::new(p.P0_21, Level::Low, OutputDrive::Standard);
+
+    loop {
+        led.set_high();
+        Timer::after_millis(300).await;
+        led.set_low();
+        Timer::after_millis(300).await;
+    }
+}