add manual overclock example, finalize API, cleanup

examples/rp/src/bin/overclock.rs

@@ -1,9 +1,13 @@
+//! # Overclocking the RP2040 to 200 MHz
+//!
+//! This example demonstrates how to configure the RP2040 to run at 200 MHz using a higher level API.
+
 #![no_std]
 #![no_main]
 
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_rp::clocks::{clk_sys_freq, ClockConfig, VoltageScale};
+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};
@@ -15,15 +19,10 @@ const COUNT_TO: i64 = 10_000_000;
 async fn main(_spawner: Spawner) -> ! {
     // Set up for clock frequency of 200 MHz
     // This will set all the necessary defaults including slightly raised voltage
-    // See embassy_rp::clocks::ClockConfig for more options, including full manual control
     let config = Config::new(ClockConfig::at_sys_frequency_mhz(200));
 
-    // Show the voltage scale and brownout-detection for verification
+    // Show the voltage scale for verification
     info!("System core voltage: {}", Debug2Format(&config.clocks.voltage_scale));
-    // info!(
-    //     "Brownout detection: {}",
-    //     Debug2Format(&config.clocks.brownout_detection)
-    // );
 
     // Initialize the peripherals
     let p = embassy_rp::init(config);
@@ -64,14 +63,3 @@ async fn main(_spawner: Spawner) -> ! {
         Timer::after(Duration::from_secs(2)).await;
     }
 }
-
-// let config = Config::new(ClockConfig::with_speed_mhz_test_voltage(125, Some(VoltageScale::V1_10)));
-// let config = Config::default();
-// let config = Config::new(ClockConfig::with_speed_mhz_test_voltage_extended_delay(
-//     200,                       // Standard 125MHz clock
-//     Some(VoltageScale::V1_15), // 1.15V voltage
-//     Some(1000),                // 1000μs (1ms) stabilization delay - significantly longer than default
-// ));
-// Initialize the peripherals
-
-// let p = embassy_rp::init(Default::default()); //testing the bog standard

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;
+    }
+}