add manual overclock example, finalize API, cleanup

1 files changed, 81 insertions, 0 deletions

diff --git a/examples/rp/src/bin/overclock_manual.rs b/examples/rp/src/bin/overclock_manual.rs
new file mode 100644
index 000000000..ad6abf0e7
--- /dev/null
+++ b/examples/rp/src/bin/overclock_manual.rs
@@ -0,0 +1,81 @@
+//! # 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, PllConfig, VoltageScale};
+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
+/// all the required parameters instead of using higher-level APIs.
+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 using a PLL with a reference frequency of 12 MHz
+    config.clocks = ClockConfig::manual_pll(
+        12_000_000,
+        PllConfig {
+            refdiv: 1,
+            fbdiv: 100,
+            post_div1: 3,
+            post_div2: 2,
+        },
+        // For 200 MHz, we need a voltage scale of 1.15V
+        Some(VoltageScale::V1_15),
+    );
+
+    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;
+    }
+}