Fix timing bugs and add documentation

[m17rt] / m17app / src / soundmodem.rs

diff --git a/m17app/src/soundmodem.rs b/m17app/src/soundmodem.rs
index 974fd45085600b8fa60d1f7cac377e765415426d..391bfadde1b66b2ee33c1b7a336991aabe126e19 100644 (file)
--- a/m17app/src/soundmodem.rs
+++ b/m17app/src/soundmodem.rs
@@ -138,8 +138,12 @@ fn spawn_soundmodem_worker(
         let mut ptt = false;
         while let Ok(ev) = event_rx.recv() {
             // Update clock on TNC before we do anything
-            let sample_time = (start.elapsed().as_nanos() / 48000) as u64;
-            tnc.set_now(sample_time);
+            let sample_time = start.elapsed();
+            let secs = sample_time.as_secs();
+            let nanos = sample_time.subsec_nanos();
+            // Accurate to within approx 1 sample
+            let now_samples = 48000 * secs + (nanos as u64 / 20833);
+            tnc.set_now(now_samples);
 
             // Handle event
             match ev {