Cleanup and comments

src/usb.rs

@@ -29,7 +29,6 @@ pub async fn usb_task(
 
     // Create embassy-usb Config
     let config = embassy_usb::Config::new(0xc0de, 0xcafe);
-    //config.max_packet_size_0 = 64;
 
     // Create embassy-usb DeviceBuilder using the driver and config.
     // It needs some buffers for building the descriptors.
@@ -38,7 +37,7 @@ pub async fn usb_task(
     let mut bos_descriptor = [0; 256];
     let mut control_buf = [0; 7];
 
-    let mut state = State::new();
+    let mut usb_state = State::new();
 
     let mut builder = Builder::new(
         driver,
@@ -51,36 +50,47 @@ pub async fn usb_task(
     );
 
     // Create classes on the builder.
-    let mut class = CdcAcmClass::new(&mut builder, &mut state, 64);
+    let mut class = CdcAcmClass::new(&mut builder, &mut usb_state, 64);
 
     // Build the builder.
     let mut usb = builder.build();
 
-    // Do stuff with the class!
+    // Create a future to handle incomming usb packets
     let usb_handler_fut = async {
+        // Initialize the current position in case we get a B or C command,
+        // before we get the first the update via pos_receiver
         let mut current_pos = AzElPair { az: 0, el: 0 };
 
         loop {
+            // No much used doing anything until we have a usb connection
             class.wait_connection().await;
             defmt::info!("USB connected");
+            // Allocate a space for incomming usb data packets
             let mut packet = [0; 64];
+            // Allocate a string to act as buffer to pares the packets linewise
             let mut buffer: String<64> = String::new();
 
             loop {
                 let n = match select(class.read_packet(&mut packet), pos_receiver.recv()).await {
+                    // The read_packet furture returned either usb data or an error.
                     Either::First(res) => match res {
+                        // In case of an error break the loop and treat it like an usb disconnect
                         Ok(n) => n,
+                        // In case of an error break the loop and treat it like an usb disconnect
                         Err(err) => {
                             defmt::error!("Unable to read packet: {}", err);
                             break;
                         }
                     },
+                    // The pos_receiver future returned a position update from moment task.
+                    // Just update position and restart loop.
                     Either::Second(pair) => {
                         current_pos = pair;
                         continue;
                     }
                 };
 
+                // Append the data in the packet buffer to the buffer string
                 for byte in &packet[..n] {
                     if buffer.len() == 64 {
                         buffer.clear();
@@ -88,91 +98,113 @@ pub async fn usb_task(
                     buffer.push(*byte as char).unwrap();
                 }
 
+                // Check if the buffer string contains a '\r'
                 let line_end = match buffer.rfind('\r') {
+                    // Carriage return found, keep the index
                     Some(n) => n,
+                    // No carriage return, wait for the next package
                     _ => continue,
                 };
 
-                defmt::info!("Line buffer: {:x}", buffer.as_bytes());
+                // The is a non-zero amount of characters before the carriage return
-
                 if line_end > 0 {
+                    // Try the parse the slice leading up to linend as a GS323 command
                     let cmd = parse_command(&buffer.as_str()[..line_end]);
                     defmt::info!("Command: {}", cmd);
 
+                    // Reverse some space for a respose to the command
                     let mut resp: String<16> = String::new();
                     match cmd {
-                        Gs232Cmd::GetAl => {
+                        // Get Azimuth command. Respond with last known azimuth
+                        Gs232Cmd::GetAz => {
                             uwrite!(&mut resp, "AZ={}\r", current_pos.az).unwrap();
                         }
-                        Gs232Cmd::GetEz => {
+                        // Get Elevation comman. Respond with last known elevation
+                        Gs232Cmd::GetEl => {
                             uwrite!(&mut resp, "EL={}\r", current_pos.el).unwrap();
                         }
-                        Gs232Cmd::GetAlEz => {
+                        // Get Azimuth and Elevation. Respond with last known pair 
+                        Gs232Cmd::GetAzEl => {
                             uwrite!(&mut resp, "AZ={} EL={}\r", current_pos.az, current_pos.el)
                                 .unwrap();
                         }
+                        // Move to command. Send to movement task. Respond with empty line.
                         Gs232Cmd::MoveTo(_) => {
                             cmd_sender.send(cmd).await;
                             resp.push_str("\r").unwrap();
                         }
+                        // Stop command. Send to movement task. Respond with empty line.
                         Gs232Cmd::Stop => {
                             cmd_sender.send(cmd).await;
                             resp.push_str("\r").unwrap();
                         }
+                        // Unknown command or parser error. Complain and do nothing.
                         _ => {
                             defmt::error!("Uknown command: {}", &buffer.as_str()[..line_end]);
                             resp.push_str("Unkown command!\r").unwrap();
                         }
                     }
-
+                    
+                    // Write the response back via USB
                     match class.write_packet(resp.as_bytes()).await {
                         Ok(_) => {}
+                        // Error treat like broken usb connection
                         Err(err) => {
                             defmt::error!("Unable to write packet: {}", err);
                             break;
                         }
                     };
                 }
+                // Drop the processed line from the buffer
                 buffer = String::from(&buffer.as_str()[line_end + 1..]);
             }
             defmt::info!("USB disconnected");
         }
     };
 
+    // Run the ubs and handler future both to completion.
+    // None of the ever completes, but they will still be polled continously.
     join(usb.run(), usb_handler_fut).await;
 }
 
+// Enum for the GS232 commands
 #[derive(Format, PartialEq)]
 pub enum Gs232Cmd {
     Unkown,
-    GetAl,
+    GetAz,
-    GetEz,
+    GetEl,
-    GetAlEz,
+    GetAzEl,
     MoveTo(AzElPair),
     Stop,
 }
 
+// Parse a GS232 commmand from a string slice
 fn parse_command(data: &str) -> Gs232Cmd {
     match data.chars().nth(0).unwrap() {
         'B' => {
+            // Get Az command. Format 'B\r'
             if data.len() == 1 {
-                Gs232Cmd::GetAl
+                Gs232Cmd::GetAz
             } else {
                 Gs232Cmd::Unkown
             }
         }
 
         'C' => {
+            // Get AZ and EL. Format 'C2\r'
             if data.len() == 2 && data.chars().nth(1).unwrap() as char == '2' {
-                Gs232Cmd::GetAlEz
+                Gs232Cmd::GetAzEl
+            // Get EL only 'C\r'
             } else if data.len() == 1 {
-                Gs232Cmd::GetEz
+                Gs232Cmd::GetEl
             } else {
                 Gs232Cmd::Unkown
             }
         }
 
         'W' => {
+            // Set position 'Waaa eee\r' with azimuth aaa and elevation eee.
+            // Fortunately rotcld will prepend zeros, so there will always be 3 digits per number.
             if data.len() == 8 {
                 if let Ok(az) = data[1..4].parse::<u16>() {
                     if let Ok(el) = data[5..].parse::<u16>() {
@@ -189,6 +221,7 @@ fn parse_command(data: &str) -> Gs232Cmd {
         }
 
         'S' => {
+            // Stop command. Format 'S\r'
             if data.len() == 1 {
                 Gs232Cmd::Stop
             } else {