From ff4823b3ad9af50bebbc02e25f08d3a1876eb12a Mon Sep 17 00:00:00 2001
From: "Daniele Verducci (ZenPenguin)" <danieleverducci@gmail.com>
Date: Sat, 2 Jan 2021 07:56:11 +0100
Subject: [PATCH] WIP Terminal interface with commands

---
 arduino/arduino_terminal/arduino_terminal.ino |  3 +-
 python/terminal_emulator.py                   | 29 ++++++++++++-------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/arduino/arduino_terminal/arduino_terminal.ino b/arduino/arduino_terminal/arduino_terminal.ino
index 97b4ab5..05fc428 100644
--- a/arduino/arduino_terminal/arduino_terminal.ino
+++ b/arduino/arduino_terminal/arduino_terminal.ino
@@ -41,9 +41,10 @@ void setup() {
 }
 
 void loop() {
-  if (Serial.available() > 0) {
+  if (Serial.available() > 1) {
     switch (Serial.read()) {
       case COMMAND_WRITE:
+	  	while (Serial.available() < 1) {}	// Waits for the second byte
         incomingBuffer = Serial.read();
         availableBytes = 1;   // TODO: Implement a 256 byte buffer and store the avail bytes number in this var
         break;
diff --git a/python/terminal_emulator.py b/python/terminal_emulator.py
index 18ed302..81034d4 100755
--- a/python/terminal_emulator.py
+++ b/python/terminal_emulator.py
@@ -31,7 +31,6 @@ import os
 
 
 class TerminalEmulator:
-    SYNC_SLEEP = 0.001
 
     def __init__(self, w, ser):
         w.clear()
@@ -48,8 +47,7 @@ class TerminalEmulator:
             key = w.getch()
             if key == 10 or (key > 31 and key < 256):
                 # Is a character
-                time.sleep(self.SYNC_SLEEP)
-                ser.write(bytes([key]))
+                self.sendByte(bytes([key]))
             elif int(key) == 1:     # CTRL+A, enter ADB mode
                 # Save cursor position
                 (xPos, yPos) = w.getyx()
@@ -82,18 +80,15 @@ class TerminalEmulator:
             w.refresh()
 
             # Send the two heading bytes (most significant first)
-            ser.write(header[0:1])
-            time.sleep(self.SYNC_SLEEP)
-            ser.write(header[1:2])
-            time.sleep(self.SYNC_SLEEP)
+            self.sendByte(header[0:1])
+            self.sendByte(header[1:2])
 
             # Send the actual binary stream
             with open(path, "rb") as f:
                 byte = f.read(1)
                 while byte:
-                    ser.write(byte)
+                    self.sendByte(byte)
                     byte = f.read(1)
-                    time.sleep(self.SYNC_SLEEP)
         except IOError as e:
             w.move(0,0)
             w.clrtoeol()
@@ -102,7 +97,21 @@ class TerminalEmulator:
 
         curses.noecho()
         stdscr.nodelay(True)
-        
+
+    # Sends a byte checking if the interface is busy
+    def sendByte(self, b):
+        busy = True
+        while busy:
+            # check if busy
+            ser.write(b'\x01') # send COMMAND_BUFFER
+            while not ser.inWaiting():
+                # wait for answer from interface
+                pass
+            busy = ser.read() != 0
+        # interface is free: write byte
+        ser.write(b'\x00') # send COMMAND_WRITE
+        ser.write(b) # send byte
+
 
 if __name__ == '__main__':
     import argparse