flush buffers

Cargo.lock

@@ -2256,7 +2256,7 @@ dependencies = [
 
 [[package]]
 name = "tesla-charge-controller"
-version = "0.1.20"
+version = "0.1.21"
 dependencies = [
  "async-channel",
  "chrono",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tesla-charge-controller"
-version = "0.1.20"
+version = "0.1.21"
 edition = "2021"
 license = "MITNFA"
 description = "Controls Tesla charge rate based on solar charge data"

src/pl_interface.rs

@@ -200,10 +200,22 @@ impl Pli {
         })
     }
 
-    fn send_command(&mut self, req: [u8; 4]) {
+    fn send_command(&mut self, req: [u8; 4]) -> Result<(), PliError> {
-        self.port
+        self.flush()?;
-            .write_all(&req)
+        self.port.write_all(&req)?;
-            .expect("failed to write to serial port");
+        Ok(())
+    }
+
+    fn flush(&mut self) -> Result<(), PliError> {
+        self.port.flush()?;
+        while let Ok(num) = self.port.bytes_to_read() {
+            if num == 0 {
+                return Ok(());
+            } else {
+                let _ = self.port.read(&mut [0; 8]);
+            }
+        }
+        Ok(())
     }
 
     fn receive<const LENGTH: usize>(&mut self) -> Result<[u8; LENGTH], PliError> {
@@ -216,8 +228,8 @@ impl Pli {
     where
         T: Into<u8>,
     {
-        self.send_command(command(20, address.into(), 0));
+        self.send_command(command(20, address.into(), 0))?;
-        let buf: [u8; 1] = self.receive()?;
+        let buf = self.receive::<1>()?;
         if buf[0] == 200 {
             Ok(self.receive::<1>()?[0])
         } else {