Merge pull request #4150 from 1-rafael-1/rp2040-overclocking

RP: rp2040 overclocking

embassy-rp/src/pio_programs/clock_divider.rs

@@ -0,0 +1,25 @@
+//! Helper functions for calculating PIO clock dividers
+
+use fixed::traits::ToFixed;
+use fixed::types::extra::U8;
+
+use crate::clocks::clk_sys_freq;
+
+/// Calculate a PIO clock divider value based on the desired target frequency.
+///
+/// # Arguments
+///
+/// * `target_hz` - The desired PIO clock frequency in Hz
+///
+/// # Returns
+///
+/// A fixed-point divider value suitable for use in a PIO state machine configuration
+#[inline]
+pub fn calculate_pio_clock_divider(target_hz: u32) -> fixed::FixedU32<U8> {
+    // Requires a non-zero frequency
+    assert!(target_hz > 0, "PIO clock frequency cannot be zero");
+
+    // Calculate the divider
+    let divider = (clk_sys_freq() + target_hz / 2) / target_hz;
+    divider.to_fixed()
+}

embassy-rp/src/pio_programs/hd44780.rs

@@ -5,6 +5,7 @@ use crate::pio::{
     Common, Config, Direction, FifoJoin, Instance, Irq, LoadedProgram, PioPin, ShiftConfig, ShiftDirection,
     StateMachine,
 };
+use crate::pio_programs::clock_divider::calculate_pio_clock_divider;
 use crate::Peri;
 
 /// This struct represents a HD44780 program that takes command words (<wait:24> <command:4> <0:4>)
@@ -134,7 +135,10 @@ impl<'l, P: Instance, const S: usize> PioHD44780<'l, P, S> {
 
         let mut cfg = Config::default();
         cfg.use_program(&word_prg.prg, &[&e]);
-        cfg.clock_divider = 125u8.into();
+
+        // Target 1 MHz PIO clock (each cycle is 1µs)
+        cfg.clock_divider = calculate_pio_clock_divider(1_000_000);
+
         cfg.set_out_pins(&[&db4, &db5, &db6, &db7]);
         cfg.shift_out = ShiftConfig {
             auto_fill: true,
@@ -160,7 +164,10 @@ impl<'l, P: Instance, const S: usize> PioHD44780<'l, P, S> {
 
         let mut cfg = Config::default();
         cfg.use_program(&seq_prg.prg, &[&e]);
-        cfg.clock_divider = 8u8.into(); // ~64ns/insn
+
+        // Target ~15.6 MHz PIO clock (~64ns/insn)
+        cfg.clock_divider = calculate_pio_clock_divider(15_600_000);
+
         cfg.set_jmp_pin(&db7);
         cfg.set_set_pins(&[&rs, &rw]);
         cfg.set_out_pins(&[&db4, &db5, &db6, &db7]);

embassy-rp/src/pio_programs/mod.rs

@@ -1,5 +1,6 @@
 //! Pre-built pio programs for common interfaces
 
+pub mod clock_divider;
 pub mod hd44780;
 pub mod i2s;
 pub mod onewire;

embassy-rp/src/pio_programs/rotary_encoder.rs

@@ -1,11 +1,10 @@
 //! PIO backed quadrature encoder
 
-use fixed::traits::ToFixed;
-
 use crate::gpio::Pull;
 use crate::pio::{
     Common, Config, Direction as PioDirection, FifoJoin, Instance, LoadedProgram, PioPin, ShiftDirection, StateMachine,
 };
+use crate::pio_programs::clock_divider::calculate_pio_clock_divider;
 use crate::Peri;
 
 /// This struct represents an Encoder program loaded into pio instruction memory.
@@ -48,7 +47,10 @@ impl<'d, T: Instance, const SM: usize> PioEncoder<'d, T, SM> {
         cfg.set_in_pins(&[&pin_a, &pin_b]);
         cfg.fifo_join = FifoJoin::RxOnly;
         cfg.shift_in.direction = ShiftDirection::Left;
-        cfg.clock_divider = 10_000.to_fixed();
+
+        // Target 12.5 KHz PIO clock
+        cfg.clock_divider = calculate_pio_clock_divider(12_500);
+
         cfg.use_program(&program.prg, &[]);
         sm.set_config(&cfg);
         sm.set_enable(true);

embassy-rp/src/pio_programs/stepper.rs

@@ -2,11 +2,8 @@
 
 use core::mem::{self, MaybeUninit};
 
-use fixed::traits::ToFixed;
-use fixed::types::extra::U8;
-use fixed::FixedU32;
-
 use crate::pio::{Common, Config, Direction, Instance, Irq, LoadedProgram, PioPin, StateMachine};
+use crate::pio_programs::clock_divider::calculate_pio_clock_divider;
 use crate::Peri;
 
 /// This struct represents a Stepper driver program loaded into pio instruction memory.
@@ -64,7 +61,9 @@ impl<'d, T: Instance, const SM: usize> PioStepper<'d, T, SM> {
         sm.set_pin_dirs(Direction::Out, &[&pin0, &pin1, &pin2, &pin3]);
         let mut cfg = Config::default();
         cfg.set_out_pins(&[&pin0, &pin1, &pin2, &pin3]);
-        cfg.clock_divider = (125_000_000 / (100 * 136)).to_fixed();
+
+        cfg.clock_divider = calculate_pio_clock_divider(100 * 136);
+
         cfg.use_program(&program.prg, &[]);
         sm.set_config(&cfg);
         sm.set_enable(true);
@@ -73,9 +72,11 @@ impl<'d, T: Instance, const SM: usize> PioStepper<'d, T, SM> {
 
     /// Set pulse frequency
     pub fn set_frequency(&mut self, freq: u32) {
-        let clock_divider: FixedU32<U8> = (125_000_000 / (freq * 136)).to_fixed();
+        let clock_divider = calculate_pio_clock_divider(freq * 136);
-        assert!(clock_divider <= 65536, "clkdiv must be <= 65536");
+        let divider_f32 = clock_divider.to_num::<f32>();
-        assert!(clock_divider >= 1, "clkdiv must be >= 1");
+        assert!(divider_f32 <= 65536.0, "clkdiv must be <= 65536");
+        assert!(divider_f32 >= 1.0, "clkdiv must be >= 1");
+
         self.sm.set_clock_divider(clock_divider);
         self.sm.clkdiv_restart();
     }

examples/rp/src/bin/overclock.rs

@@ -0,0 +1,64 @@
+//! # Overclocking the RP2040 to 200 MHz
+//!
+//! This example demonstrates how to configure the RP2040 to run at 200 MHz.
+
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::clocks::{clk_sys_freq, ClockConfig};
+use embassy_rp::config::Config;
+use embassy_rp::gpio::{Level, Output};
+use embassy_time::{Duration, Instant, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+const COUNT_TO: i64 = 10_000_000;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    // Set up for clock frequency of 200 MHz, setting all necessary defaults.
+    let config = Config::new(ClockConfig::system_freq(200_000_000));
+
+    // Show the voltage scale for verification
+    info!("System core voltage: {}", Debug2Format(&config.clocks.core_voltage));
+
+    // Initialize the peripherals
+    let p = embassy_rp::init(config);
+
+    // Show CPU frequency for verification
+    let sys_freq = clk_sys_freq();
+    info!("System clock frequency: {} MHz", sys_freq / 1_000_000);
+
+    // LED to indicate the system is running
+    let mut led = Output::new(p.PIN_25, Level::Low);
+
+    loop {
+        // Reset the counter at the start of measurement period
+        let mut counter = 0;
+
+        // Turn LED on while counting
+        led.set_high();
+
+        let start = Instant::now();
+
+        // This is a busy loop that will take some time to complete
+        while counter < COUNT_TO {
+            counter += 1;
+        }
+
+        let elapsed = Instant::now() - start;
+
+        // Report the elapsed time
+        led.set_low();
+        info!(
+            "At {}Mhz: Elapsed time to count to {}: {}ms",
+            sys_freq / 1_000_000,
+            counter,
+            elapsed.as_millis()
+        );
+
+        // Wait 2 seconds before starting the next measurement
+        Timer::after(Duration::from_secs(2)).await;
+    }
+}

examples/rp/src/bin/overclock_manual.rs

@@ -0,0 +1,79 @@
+//! # Overclocking the RP2040 to 200 MHz manually
+//!
+//! This example demonstrates how to manually configure the RP2040 to run at 200 MHz.
+
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::clocks;
+use embassy_rp::clocks::{ClockConfig, CoreVoltage, PllConfig};
+use embassy_rp::config::Config;
+use embassy_rp::gpio::{Level, Output};
+use embassy_time::{Duration, Instant, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+const COUNT_TO: i64 = 10_000_000;
+
+/// Configure the RP2040 for 200 MHz operation by manually specifying the PLL settings.
+fn configure_manual_overclock() -> Config {
+    // Set the PLL configuration manually, starting from default values
+    let mut config = Config::default();
+
+    // Set the system clock to 200 MHz
+    config.clocks = ClockConfig::manual_pll(
+        12_000_000, // Crystal frequency, 12 MHz is common. If using custom, set to your value.
+        PllConfig {
+            refdiv: 1,    // Reference divider
+            fbdiv: 100,   // Feedback divider
+            post_div1: 3, // Post divider 1
+            post_div2: 2, // Post divider 2
+        },
+        CoreVoltage::V1_15, // Core voltage, should be set to V1_15 for 200 MHz
+    );
+
+    config
+}
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    // Initialize with our manual overclock configuration
+    let p = embassy_rp::init(configure_manual_overclock());
+
+    // Verify the actual system clock frequency
+    let sys_freq = clocks::clk_sys_freq();
+    info!("System clock frequency: {} MHz", sys_freq / 1_000_000);
+
+    // LED to indicate the system is running
+    let mut led = Output::new(p.PIN_25, Level::Low);
+
+    loop {
+        // Reset the counter at the start of measurement period
+        let mut counter = 0;
+
+        // Turn LED on while counting
+        led.set_high();
+
+        let start = Instant::now();
+
+        // This is a busy loop that will take some time to complete
+        while counter < COUNT_TO {
+            counter += 1;
+        }
+
+        let elapsed = Instant::now() - start;
+
+        // Report the elapsed time
+        led.set_low();
+        info!(
+            "At {}Mhz: Elapsed time to count to {}: {}ms",
+            sys_freq / 1_000_000,
+            counter,
+            elapsed.as_millis()
+        );
+
+        // Wait 2 seconds before starting the next measurement
+        Timer::after(Duration::from_secs(2)).await;
+    }
+}

tests/rp/src/bin/overclock.rs

@@ -0,0 +1,70 @@
+#![no_std]
+#![no_main]
+
+#[cfg(feature = "rp2040")]
+teleprobe_meta::target!(b"rpi-pico");
+#[cfg(feature = "rp235xb")]
+teleprobe_meta::target!(b"pimoroni-pico-plus-2");
+
+use defmt::info;
+#[cfg(feature = "rp2040")]
+use defmt::{assert, assert_eq};
+use embassy_executor::Spawner;
+use embassy_rp::clocks;
+#[cfg(feature = "rp2040")]
+use embassy_rp::clocks::ClockConfig;
+#[cfg(feature = "rp2040")]
+use embassy_rp::clocks::CoreVoltage;
+use embassy_rp::config::Config;
+use embassy_time::Instant;
+use {defmt_rtt as _, panic_probe as _};
+
+const COUNT_TO: i64 = 10_000_000;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    #[cfg(feature = "rp2040")]
+    let mut config = Config::default();
+    #[cfg(not(feature = "rp2040"))]
+    let config = Config::default();
+
+    // Initialize with 200MHz clock configuration for RP2040, other chips will use default clock
+    #[cfg(feature = "rp2040")]
+    {
+        config.clocks = ClockConfig::system_freq(200_000_000);
+        let voltage = config.clocks.core_voltage;
+        assert!(matches!(voltage, CoreVoltage::V1_15), "Expected voltage scale V1_15");
+    }
+
+    let _p = embassy_rp::init(config);
+
+    // Test the system speed
+    let (time_elapsed, clk_sys_freq) = {
+        let mut counter = 0;
+        let start = Instant::now();
+        while counter < COUNT_TO {
+            counter += 1;
+        }
+        let elapsed = Instant::now() - start;
+
+        (elapsed.as_millis(), clocks::clk_sys_freq())
+    };
+
+    // Report the elapsed time, so that the compiler doesn't optimize it away for chips other than RP2040
+    info!(
+        "At {}Mhz: Elapsed time to count to {}: {}ms",
+        clk_sys_freq / 1_000_000,
+        COUNT_TO,
+        time_elapsed
+    );
+
+    #[cfg(feature = "rp2040")]
+    {
+        // we should be at 200MHz
+        assert_eq!(clk_sys_freq, 200_000_000, "System clock frequency is not 200MHz");
+        // At 200MHz, the time to count to 10_000_000 should be at 600ms, testing with 1% margin
+        assert!(time_elapsed <= 606, "Elapsed time is too long");
+    }
+
+    cortex_m::asm::bkpt();
+}