222 lines
6.4 KiB
C++
222 lines
6.4 KiB
C++
/* ************** DEBUGGER Zilog Z80 ******************
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HARDWARE:
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CORRISPONDENZA PIN CPU -> ARDUINO MEGA 2560
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Arduino A12 A15 A14 53 51 49 47 45 43 41 39 37 35 33 31 29 27 25 23 20
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Cpu 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21
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__________________________________________________________________________________________________
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|_) Zilog Z80 |
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|__________________________________________________________________________________________________|
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Cpu 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
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Arduino A8 A9 A11 52 50 21 46 44 42 40 38 36 34 32 30 28 26 24 22 A13
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CORRISPONDENZA FUNZIONALE:
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Address bus (A0...A15): 39, 41, 43, 45, 47, 49, 51, 53, A14, A15, A12, A8, A9, A11, 52, 50
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Data bus (D0...D7): 32, 30, 36, 44, 46, 42, 40, 34
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Control bus:
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CLK 21
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INT 28
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NMI 26
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HALT 24
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MREQ 22
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IORQ A13
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RFSH 35
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RD 20
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WR 23
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BUSACK 25
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WAIT 27
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BUSREQ 29
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RESET 31
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M1 33
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Other
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GND 37, GND
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Vcc 38
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*/
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const byte MODE_DEBUGGER = 0;
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const byte MODE_ROM_EMULATOR = 1;
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const byte MODE_ROM_RAM_EMULATOR = 2;
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const byte ADDR_BUS[] = {50, 52, A11, A9, A8, A12, A15, A14, 53, 51, 49, 47, 45, 43, 41, 39};
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//const byte DATA_BUS[] = {34, 40, 42, 44, 46, 36, 30, 32};
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const byte DATA_BUS[] = {3, 4, 5, 6, 7, 8, 9,10};
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//const byte CTRL_BUS_RD = 20;
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const byte CTRL_BUS_RD = 3;
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const byte CTRL_BUS_WR = 23;
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const byte CTRL_BUS_BUSACK = 25;
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const byte CTRL_BUS_WAIT = 27;
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const byte CTRL_BUS_BUSREQ = 29;
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const byte CTRL_BUS_RESET = 31;
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const byte CTRL_BUS_M1 = 33;
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const byte CTRL_BUS_REFRESH = 35;
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const byte CTRL_BUS_IORQ = A13;
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const byte CTRL_BUS_MREQ = 22;
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const byte CTRL_BUS_HALT = 24;
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const byte CTRL_BUS_NMI = 26;
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//const byte CTRL_BUS_CLK= 21;
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const byte CTRL_BUS_CLK= 2;
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const byte CTRL_BUS_INT = 28;
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const byte PWR_GND = 37;
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const byte PWR_VCC = 38;
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/*
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* SETUP
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* Mode:
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* MODE_DEBUGGER = Debugger (stays in high impedance mode listening to inputs/outputs on data, address and control buses)
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* MODE_ROM_EMULATOR = Emulates rom with the contents of ROM_DATA
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* MODE_ROM_RAM_EMULATOR = Emulates ram
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*/
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const byte MODE = MODE_DEBUGGER;
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const byte ROM_DATA[] = {0x00, 0x00, 0x00, 0x00, 0xC3, 0x00, 0x00};
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//const byte ROM_DATA[] = {0x00, 0x00, 0x00, 0x00, 0x76, 0x00, 0x00};
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void setup() {
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Serial.begin(57600);
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Serial.print("Started in mode ");
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switch(MODE) {
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case MODE_DEBUGGER:
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Serial.println("debugger");
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break;
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case MODE_ROM_EMULATOR:
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Serial.println("rom emulator");
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break;
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case MODE_ROM_RAM_EMULATOR:
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Serial.println("rom/ram emulator");
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break;
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}
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for(int pin=0; pin < 16; pin++) {
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pinMode(ADDR_BUS[pin], INPUT);
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}
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setDataBusAs(INPUT);
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pinMode(CTRL_BUS_RD, INPUT);
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pinMode(CTRL_BUS_WR, INPUT);
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pinMode(CTRL_BUS_BUSACK, INPUT);
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pinMode(CTRL_BUS_WAIT, INPUT);
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pinMode(CTRL_BUS_BUSREQ, INPUT);
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pinMode(CTRL_BUS_RESET, INPUT);
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pinMode(CTRL_BUS_M1, INPUT);
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pinMode(CTRL_BUS_REFRESH, INPUT);
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pinMode(CTRL_BUS_IORQ, INPUT);
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pinMode(CTRL_BUS_MREQ, INPUT);
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pinMode(CTRL_BUS_HALT, INPUT);
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pinMode(CTRL_BUS_NMI, INPUT);
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pinMode(CTRL_BUS_CLK, INPUT);
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pinMode(CTRL_BUS_INT, INPUT);
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// Set power pins to high impedance, even if we aren't going to read them, to avoid shorts
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pinMode(PWR_GND, INPUT);
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pinMode(PWR_VCC, INPUT);
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attachInterrupt(digitalPinToInterrupt(CTRL_BUS_CLK), onClk, RISING);
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}
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void onClk() {
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setDataBusAs(INPUT);
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switch (MODE) {
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case MODE_DEBUGGER:
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debugCycle();
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break;
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case MODE_ROM_EMULATOR:
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emulateRomCycle();
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break;
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default:
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Serial.println("Unimplemented mode");
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}
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}
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void loop() {}
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void debugCycle() {
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if (!digitalRead(CTRL_BUS_RD) || !digitalRead(CTRL_BUS_WR)) { //RD e WR are active-low
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unsigned int address = getAddress();
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unsigned int data = getData();
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char output[30] = {};
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sprintf(output, "%04x %c%c %02x %s", address, digitalRead(CTRL_BUS_RD) ? '-' : 'r', digitalRead(CTRL_BUS_WR) ? '-' : 'w', data, digitalRead(CTRL_BUS_RESET) ? "" : "reset");
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Serial.println(output);
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}
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}
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void emulateRomCycle() {
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if (!digitalRead(CTRL_BUS_RD)) { //RD e WR are active-low
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unsigned int addr = getAddress();
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if (addr < sizeof(ROM_DATA)) {
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unsigned int data = ROM_DATA[addr];
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writeByteToDataBus(data);
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char output[30] = {};
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sprintf(output, "%04x r- %02x Emu ROM read", addr, data);
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Serial.println(output);
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}
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}
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if (!digitalRead(CTRL_BUS_WR)) {
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debugCycle();
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}
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}
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unsigned int getAddress() {
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unsigned int address = 0;
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for(int pin=0; pin < 16; pin++) {
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byte b = digitalRead(ADDR_BUS[pin]) ? 1 : 0;
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//Serial.print(b);
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address = (address << 1) + b; // Shifta di 1 e aggiunge il bit corrente. Serve per ricostruire il numero da binario
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}
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return address;
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}
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unsigned int getData() {
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unsigned int data = 0;
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for(int pin=0; pin < 8; pin++) {
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byte b = digitalRead(DATA_BUS[pin]) ? 1 : 0;
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//Serial.print(b);
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data = (data << 1) + b; // Shifta di 1 e aggiunge il bit corrente. Serve per ricostruire il numero da binario
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}
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return data;
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}
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void setDataBusAs(byte mode){
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for(int pin=0; pin < 8; pin++) {
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pinMode(DATA_BUS[pin], mode);
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}
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}
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void writeByteToDataBus(byte j) {
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setDataBusAs(OUTPUT);
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for (int n=0; n<8; n++)
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{
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if((0x01&j) < 0x01)
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{
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digitalWrite(DATA_BUS[n],LOW);
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} else {
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digitalWrite(DATA_BUS[n],HIGH);
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}
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j>>=1;
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}
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}
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