From 7caf4124ad18033fa6270644ed0493535365e998 Mon Sep 17 00:00:00 2001 From: Vadim Kaushan Date: Sun, 23 Aug 2020 21:38:33 +0300 Subject: [PATCH 1/5] Provide a delay driver based on SysTick --- Cargo.toml | 1 + src/delay.rs | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++ src/lib.rs | 1 + 3 files changed, 121 insertions(+) create mode 100644 src/delay.rs diff --git a/Cargo.toml b/Cargo.toml index e995d82e..2e55f6ad 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -19,6 +19,7 @@ links = "cortex-m" # prevent multiple versions of this crate to be linked toget bare-metal = { version = "0.2.0", features = ["const-fn"] } volatile-register = "0.2.0" bitfield = "0.13.2" +embedded-hal = "0.2.4" [package.metadata.docs.rs] targets = [ diff --git a/src/delay.rs b/src/delay.rs new file mode 100644 index 00000000..fe79f248 --- /dev/null +++ b/src/delay.rs @@ -0,0 +1,119 @@ +//! A delay driver based on SysTick + +use crate::peripheral::{syst::SystClkSource, SYST}; +use embedded_hal::blocking::delay::{DelayMs, DelayUs}; + +/// System timer (SysTick) as a delay provider +pub struct Delay { + syst: SYST, + ahb_frequency: u32, +} + +impl Delay { + /// Configures the system timer (SysTick) as a delay provider + /// + /// `ahb_frequency` is a frequency of the AHB bus in Hz + #[inline] + pub fn new(mut syst: SYST, ahb_frequency: u32) -> Self { + syst.set_clock_source(SystClkSource::Core); + + Delay { syst, ahb_frequency } + } + + /// Releases the system timer (SysTick) resource + #[inline] + pub fn free(self) -> SYST { + self.syst + } + + fn _delay_us(&mut self, us: u32) { + let ticks = (us as u64) * (self.ahb_frequency as u64) / 1_000_000; + + let full_cycles = ticks >> 24; + if full_cycles > 0 { + self.syst.set_reload(0xffffff); + self.syst.clear_current(); + self.syst.enable_counter(); + + for _ in 0..full_cycles { + while !self.syst.has_wrapped() {} + } + } + + let ticks = (ticks & 0xffffff) as u32; + if ticks > 1 { + self.syst.set_reload(ticks - 1); + self.syst.clear_current(); + self.syst.enable_counter(); + + while !self.syst.has_wrapped() {} + } + + self.syst.disable_counter(); + } +} + +impl DelayMs for Delay { + #[inline] + fn delay_ms(&mut self, mut ms: u32) { + // 4294967 is the highest u32 value which you can multiply by 1000 without overflow + while ms > 4294967 { + self.delay_us(4294967000u32); + ms -= 4294967; + } + self.delay_us(ms * 1_000); + } +} + +// This is a workaround to allow `delay_ms(42)` construction without specifying a type. +impl DelayMs for Delay { + #[inline(always)] + fn delay_ms(&mut self, ms: i32) { + assert!(ms >= 0); + self.delay_ms(ms as u32); + } +} + +impl DelayMs for Delay { + #[inline(always)] + fn delay_ms(&mut self, ms: u16) { + self.delay_ms(u32::from(ms)); + } +} + +impl DelayMs for Delay { + #[inline(always)] + fn delay_ms(&mut self, ms: u8) { + self.delay_ms(u32::from(ms)); + } +} + +impl DelayUs for Delay { + #[inline] + fn delay_us(&mut self, us: u32) { + self._delay_us(us); + } +} + +// This is a workaround to allow `delay_us(42)` construction without specifying a type. +impl DelayUs for Delay { + #[inline(always)] + fn delay_us(&mut self, us: i32) { + assert!(us >= 0); + self.delay_us(us as u32); + } +} + +impl DelayUs for Delay { + #[inline(always)] + fn delay_us(&mut self, us: u16) { + self.delay_us(u32::from(us)) + } +} + +impl DelayUs for Delay { + #[inline(always)] + fn delay_us(&mut self, us: u8) { + self.delay_us(u32::from(us)) + } +} diff --git a/src/lib.rs b/src/lib.rs index 89f420de..109575c0 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -61,6 +61,7 @@ mod macros; pub mod asm; #[cfg(armv8m)] pub mod cmse; +pub mod delay; pub mod interrupt; #[cfg(all(not(armv6m), not(armv8m_base)))] pub mod itm; From 7839a6a602015b3ad351584640642915477eb20d Mon Sep 17 00:00:00 2001 From: Vadim Kaushan Date: Sun, 23 Aug 2020 21:58:30 +0300 Subject: [PATCH 2/5] Add change log entry --- CHANGELOG.md | 1 + 1 file changed, 1 insertion(+) diff --git a/CHANGELOG.md b/CHANGELOG.md index e6ad454a..558f07a4 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/). various NVIC functions, replacing the previous use of `Nr` from bare-metal. - Associated const `PTR` is introduced to Core Peripherals to eventually replace the existing `ptr()` API. +- A delay driver based on SysTick. ## [v0.6.2] - 2020-01-12 From 009e6291fae5a396e67a3215d4adb49fa7879981 Mon Sep 17 00:00:00 2001 From: Vadim Kaushan Date: Mon, 24 Aug 2020 02:52:10 +0300 Subject: [PATCH 3/5] Update src/delay.rs Co-authored-by: Jonas Schievink --- src/delay.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/delay.rs b/src/delay.rs index fe79f248..c83fbc96 100644 --- a/src/delay.rs +++ b/src/delay.rs @@ -1,4 +1,4 @@ -//! A delay driver based on SysTick +//! A delay driver based on SysTick. use crate::peripheral::{syst::SystClkSource, SYST}; use embedded_hal::blocking::delay::{DelayMs, DelayUs}; From db4f92a8d26043c7599827dbbeaa0fcdff7e1ee2 Mon Sep 17 00:00:00 2001 From: Vadim Kaushan Date: Mon, 24 Aug 2020 03:09:39 +0300 Subject: [PATCH 4/5] Add prelude --- src/lib.rs | 1 + src/prelude.rs | 3 +++ 2 files changed, 4 insertions(+) create mode 100644 src/prelude.rs diff --git a/src/lib.rs b/src/lib.rs index 109575c0..5dbb8f56 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -66,6 +66,7 @@ pub mod interrupt; #[cfg(all(not(armv6m), not(armv8m_base)))] pub mod itm; pub mod peripheral; +pub mod prelude; pub mod register; pub use crate::peripheral::Peripherals; diff --git a/src/prelude.rs b/src/prelude.rs new file mode 100644 index 00000000..bc47cc02 --- /dev/null +++ b/src/prelude.rs @@ -0,0 +1,3 @@ +//! Prelude + +pub use embedded_hal::prelude::*; From 2b50dce2d4bdde42ed069f721488179c1a499d3d Mon Sep 17 00:00:00 2001 From: Vadim Kaushan Date: Tue, 25 Aug 2020 20:12:14 +0300 Subject: [PATCH 5/5] Moar full stops. --- src/delay.rs | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/delay.rs b/src/delay.rs index c83fbc96..051151fa 100644 --- a/src/delay.rs +++ b/src/delay.rs @@ -3,16 +3,16 @@ use crate::peripheral::{syst::SystClkSource, SYST}; use embedded_hal::blocking::delay::{DelayMs, DelayUs}; -/// System timer (SysTick) as a delay provider +/// System timer (SysTick) as a delay provider. pub struct Delay { syst: SYST, ahb_frequency: u32, } impl Delay { - /// Configures the system timer (SysTick) as a delay provider + /// Configures the system timer (SysTick) as a delay provider. /// - /// `ahb_frequency` is a frequency of the AHB bus in Hz + /// `ahb_frequency` is a frequency of the AHB bus in Hz. #[inline] pub fn new(mut syst: SYST, ahb_frequency: u32) -> Self { syst.set_clock_source(SystClkSource::Core); @@ -20,7 +20,7 @@ impl Delay { Delay { syst, ahb_frequency } } - /// Releases the system timer (SysTick) resource + /// Releases the system timer (SysTick) resource. #[inline] pub fn free(self) -> SYST { self.syst