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