rp235x overclocking

examples/rp/src/bin/overclock.rs

@@ -7,7 +7,7 @@
 
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_rp::clocks::{clk_sys_freq, ClockConfig};
+use embassy_rp::clocks::{clk_sys_freq, core_voltage, ClockConfig};
 use embassy_rp::config::Config;
 use embassy_rp::gpio::{Level, Output};
 use embassy_time::{Duration, Instant, Timer};
@@ -20,15 +20,15 @@ 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);
+    // Show core voltage for verification
+    let core_voltage = core_voltage().unwrap();
+    info!("Core voltage: {}", Debug2Format(&core_voltage));
 
     // LED to indicate the system is running
     let mut led = Output::new(p.PIN_25, Level::Low);

examples/rp/src/bin/overclock_manual.rs

@@ -7,8 +7,7 @@
 
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_rp::clocks;
-use embassy_rp::clocks::{ClockConfig, CoreVoltage, PllConfig};
+use embassy_rp::clocks::{clk_sys_freq, core_voltage, ClockConfig, CoreVoltage, PllConfig};
 use embassy_rp::config::Config;
 use embassy_rp::gpio::{Level, Output};
 use embassy_time::{Duration, Instant, Timer};
@@ -41,9 +40,12 @@ 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();
+    // Show CPU frequency for verification
+    let sys_freq = clk_sys_freq();
     info!("System clock frequency: {} MHz", sys_freq / 1_000_000);
+    // Show core voltage for verification
+    let core_voltage = core_voltage().unwrap();
+    info!("Core voltage: {}", Debug2Format(&core_voltage));
 
     // LED to indicate the system is running
     let mut led = Output::new(p.PIN_25, Level::Low);

examples/rp235x/src/bin/overclock.rs

@@ -0,0 +1,74 @@
+//! # Overclocking the RP2350 to 200 MHz
+//!
+//! This example demonstrates how to configure the RP2350 to run at 200 MHz instead of the default 150 MHz.
+//!
+//! ## Note
+//!
+//! As of yet there is no official support for running the RP235x at higher clock frequencies and/or other core voltages than the default.
+//! Doing so may cause unexpected behavior and/or damage the chip.
+
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::clocks::{clk_sys_freq, core_voltage, ClockConfig, CoreVoltage};
+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 mut config = Config::new(ClockConfig::system_freq(200_000_000));
+
+    // since for the rp235x there is no official support for higher clock frequencies, `system_freq()` will not set a voltage for us.
+    // We need to guess the core voltage, that is needed for the higher clock frequency. Going with a small increase from the default 1.1V here, based on
+    // what we know about the RP2040. This is not guaranteed to be correct.
+    config.clocks.core_voltage = CoreVoltage::V1_15;
+
+    // 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);
+    // Show core voltage for verification
+    let core_voltage = core_voltage().unwrap();
+    info!("Core voltage: {}", Debug2Format(&core_voltage));
+
+    // 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;
+    }
+}