Working echo test for arduino terminal

arduino/arduino_terminal/arduino_terminal.ino

@@ -0,0 +1,62 @@
+/**
+ * Terminal interface.
+ * This sketch allow an Arduino to be used as a terminal to log into Pat80.
+ * The Arduino is connected to the Pat80 I/O bus and to the terminal computer via USB.
+ * The Arduino IDE serial monitor is used to send and receive commands to the Z80.
+ */
+
+#define EN 2   // Active low
+#define WR 11   // Active low
+// DATA BUS IS: 3, 4, 5, 6, 7, 8, 9, 10;
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("Pat80 terminal");
+  
+  pinMode(EN, INPUT);
+  pinMode(WR, INPUT);
+  DDRD = B00000010; // Port D (used arduino pins 2 to 7) is input. Avoid changing serial pins.
+  DDRB = B00000000; // Port B (used arduino pins 8 and 9) is input
+  attachInterrupt(digitalPinToInterrupt(EN), onClk, CHANGE);
+}
+
+void loop() {}
+
+void onClk() {
+  if (digitalRead(EN)) {
+    // Clock pulse finished, return to high impedance state
+    DDRD = B00000010;
+    DDRB = B00000000;
+  } else {
+    // Clock pulse started
+    if (digitalRead(WR)) {      
+      // Pat80 wants to Read (we send data)
+      DDRD = DDRD | B11111000; // Port D (arduino pins 3 to 7) is output. In or to preserve serial pins and interrupt pin
+      DDRB = B00000111; // Port B (0,1,2) = pins 8,9,10 output
+      byte incomingByte = 0;  // Defaults to NULL
+      // Check if serial data available
+      if (Serial.available() > 0) {
+        incomingByte = Serial.read();
+      }
+      // Split byte to two parts
+      byte wbPortD = incomingByte << 3;
+      byte wbPortB = incomingByte >> 5;
+      PORTD = wbPortD;
+      PORTB = wbPortB;
+    } else {
+      // Pat80 wants to Write (we receive data)
+      byte rb = (PIND >> 3) | (PINB << 5); // Compose the final byte from the two parts
+      if (rb == 0)
+        return; // NULL
+      if ((rb >= 8 && rb <= 13) || (rb >= 32 && rb <= 127)) {
+        // Printable character
+        Serial.print((char)rb);
+      } else {
+        // Non-printable character
+        Serial.print("[0x");
+        Serial.print(rb, HEX);
+        Serial.print("]");
+      }
+    }
+  }
+}

assembly/bios/main.asm

@@ -49,30 +49,41 @@ KEYB_A4_REG: EQU IO_1 + %00010000
 
 ; CONSTANTS
 SYSINIT_GREETING:
-    DB "Pat80",0  ; null terminated string
+    DB "Pat80",10,0  ; null terminated string
 
 
 
 
 
 include 'driver_hd44780.asm'
-include 'driver_keyboard.asm'
+;include 'driver_keyboard.asm'
 
 ; System initialization
 Sysinit:
-    call Lcd_init
+    ;call Lcd_init
 
     ; position to line 2 char 3
     ;ld b, 1
     ;ld c, 1
     ;call Lcd_locate
-    
+
+    ; I/O TEST
+     
     ; write characters to display
     ld bc, SYSINIT_GREETING
     call Lcd_print      ; write string to screen
+    _io_test_loop:   
+        in a, (IO_0)    ; legge dal terminale
+        cp 0
+        jp z, _io_test_loop
+        ;sub a, 32   ; trasforma in maiuscola (ascii - 32) 
+        out (IO_0), a   ; scrive la lettera trasformata        
+    jp _io_test_loop
+
+    halt
 
     ; poll keyboard
-    _poll_keyb:
+    ;_poll_keyb:
-    call Keyb_read
+    ;call Keyb_read
-    jp _poll_keyb
+    ;jp _poll_keyb