From 6dd49234df38305782c416677b664a48ab64b8db Mon Sep 17 00:00:00 2001
From: Sebastian <sebastian@sebastians-site.de>
Date: Sun, 21 Jan 2024 01:28:43 +0100
Subject: [PATCH] Switched to integer math to save flash space

---
 firmware/src/main.rs | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/firmware/src/main.rs b/firmware/src/main.rs
index 96b7a62..aba29d0 100644
--- a/firmware/src/main.rs
+++ b/firmware/src/main.rs
@@ -66,7 +66,7 @@ mod app {
         buffer: Vec<u8, USB_BUFFER_SIZE>,
     }
 
-    const TARGET_FREQ: f64 = 10.0f64;
+    const TARGET_FREQ: u64 = 10_000_000_000; // in millihertz
 
     #[init]
     fn init(cx: init::Context) -> (Shared, Local) {
@@ -288,11 +288,11 @@ mod app {
 
         let mut last_ic = ic2 << 16 | ic1;
 
-        let mut samples: [f64; WINDOW_LEN] = [10.0; WINDOW_LEN];
-        let mut short_avg: f64 = 10.0;
+        let mut samples: [u64; WINDOW_LEN] = [10_000_000_000; WINDOW_LEN];
+        let mut short_avg: u64 = 10_000_000_000;
 
         loop {
-            let mut last_freq = 10.0f64;
+            let mut last_freq: u64 = 10_000_000_000;
 
             let mut count = 0;
             while count < WINDOW_LEN {
@@ -317,26 +317,28 @@ mod app {
 
                 last_ic = sum_ic;
 
-                let freq = (diff_ic as f64) / 1_000_000f64;
-                defmt::info!("freq:\t{} MHz", freq);
+                let freq = (diff_ic as u64) * 1000;
+                defmt::info!("freq:\t{} mHz", freq as i64);
+                defmt::info!("last_freq:\t{} mHz", last_freq as i64);
 
-                let diff = freq - last_freq;
+                let diff = freq as i64 - last_freq as i64;
                 last_freq = freq;
-                if diff > 0.000_100 || diff < -0.000_100 {
+                if diff.abs() > 50_000 {
                     defmt::info!("Out of range, dropping sample.");
                     continue;
                 }
 
                 samples[count] = freq;
-                short_avg = 0.0;
+                short_avg = 0;
                 for i in 0..WINDOW_LEN {
-                    short_avg += samples[i] / WINDOW_LEN as f64;
+                    short_avg += samples[i];
                 }
-                defmt::info!("short_avg:\t{} MHz", short_avg);
+                short_avg = short_avg / WINDOW_LEN as u64;
+                defmt::info!("short_avg:\t{} mHz", short_avg);
 
                 cx.shared.device_status.lock(|device_status| {
-                    device_status.measured_frequency = freq;
-                    device_status.average_frequency = short_avg;
+                    device_status.measured_frequency = (freq as f64) / 1_000_000_000.0;
+                    device_status.average_frequency = (short_avg as f64) / 1_000_000_000.0;
                     device_status.pwm = cur_pwm as u16;
                 });
 
@@ -344,14 +346,12 @@ mod app {
                 board_led.toggle();
             }
 
-            defmt::info!("short_avg:\t{} MHz", short_avg);
-
-            let diff = (TARGET_FREQ - short_avg) * 1_000_000.0;
-            if diff > 0.1 || diff < -0.1 {
-                cur_pwm += (diff * 30.0) as i32;
-            } else if diff < -0.01 {
+            let diff = TARGET_FREQ as i64 - short_avg as i64;
+            if diff.abs() > 100 {
+                cur_pwm += (diff * 30 / 1000) as i32;
+            } else if diff < -10 {
                 cur_pwm -= 1;
-            } else if diff > 0.01 {
+            } else if diff > 10 {
                 cur_pwm += 1;
             }