Merge branch 'master' into TerminalWithCommands

pat80-io-devices/parallel-terminal/arduino/arduino_terminal/arduino_terminal.ino

@@ -5,6 +5,12 @@
  * The Python Terminal Monitor or the Arduino IDE serial monitor is used to send 
  * and receive commands to/from the Z80.
  * 
+ * Seen from the PC, the terminal receives two bytes: a command byte and a value byte.
+ * Commands:
+ *  0x00 WRITE:     The next byte is sent as-is to Pat80. If the terminal interface buffer
+ *                  is not empty, the new byte will replace the older one.
+ *  0x01 BUFFER:    The terminal interface returns the number of bytes waiting to be sent.
+ * 
  * Seen from the Pat80, the terminal interface has two registers:
  * DATA Register at addr 0x00 (\RS) contains the last received byte from the pc
  * DATA_AVAILABLE Register at addr 0x01 (RS) contains the number of bytes in the buffer,
@@ -17,6 +23,9 @@
 // RS 12   // Input, low = DATA register, high = DATA_AVAILABLE register
 // DATA BUS (Input/Output, active high): 3, 4, 5, 6, 7, 8, 9, 10;
 
+const byte COMMAND_WRITE = 0x00;
+const byte COMMAND_BUFFER = 0x01;
+
 byte incomingBuffer = 0;  // Incoming from computer, to the Pat80
 byte outgoingBuffer = 0;  // Outgoing to computer, from the Pat80
 byte availableBytes = 0;  // Available bytes in the incoming buffer (for the DATA_AVAILABLE register)
@@ -32,10 +41,19 @@ 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;
+      case COMMAND_BUFFER:
+        Serial.write(availableBytes);
+        break;
     }    
+  }
+  
   if (outgoingBuffer != 0) {
     if ((outgoingBuffer >= 8 && outgoingBuffer <= 13) || (outgoingBuffer >= 32 && outgoingBuffer <= 127)) {
       // Printable character

pat80-io-devices/parallel-terminal/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()
@@ -82,10 +80,8 @@ 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:
@@ -105,6 +101,20 @@ 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