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monsonite/ROMulator3.ino

Created June 4, 2016 18:04
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A ROM Emulator for Z80 retro computer - using a 62256 SRAM, 2 x 74HC595 and 74HC245
Raw
ROMulator3.ino
//--------------------------------------------------------------------------------------------
// ROMulator 3
// Compiled using Arduino 1.65 or later
// A customised vesrion of SIMPL to allow RAM and Z80 bus to be exercised using SIMPL.
// Address is st using a pair of 74HC595 shift registers
// Data is passed through a 74HC245 bi-directional bugger
// TRISTATE line when raised isolates the address and data registers from the Z80 bus - allowing it to run
// RESET - active low is used to put the Z80 into RESET so that the RAM can be loaded
// Other active low bus control lines are READ, WRITE, RAM_SEL (/CS) and IORQ
// Basic memory r/w Commands are as follows - values are integer decimal
// 170 55w write the value of 170 to address 55
// 32760 44w write the value 44 to the RAM address 32760
// 55r read and print the value stored at address 55
// 132n output 132 on the ROmulator data port
// 240q output an 8 bit address 240 on the lower address lines (for I/O operations)
// -------------------------------------------------------------------------------------------
#define bufRead(addr) (*(unsigned char *)(addr))
#define bufWrite(addr, b) (*(unsigned char *)(addr) = (b))
unsigned char bite;
unsigned int x = 0;
unsigned int y = 0;
int len = 48;
// Define the I?O pins to be used with the shift registers
int sinPin = 5; // Serial input pin from 74HC165
int sclkPin = 6; // Clock pin to 74HC165
int loadPin = 7; // parallel load pin of 74HC165
int latchPin = 8; //Pin connected to ST_CP of 74HC595 - white
int dataPin = 12; //Pin connected to DS of 74HC595 - green
int clockPin = 11; //Pin connected to SH_CP of 74HC595 - blue
// Z80 Bus Control lines - all active low Digital Outputs
int RAM_SEL=14;
int READ = 15;
int WRITE = 16;
int TRISTATE = 17;
int IORQ = 18;
int RESET = 19;
char array[26][48] = { // Define a 26 x 64 array for the colon definitions
{"6d75{1o708u0o708u}"},
{"9rP8rP12rP4rP6rP2rP3rP1rP"}, // A backward step on a stepper motor
{"6d91{1o585u0o585u}"},
{"6d100{1o532u0o532u}"},
{"6d110{1o484u0o484u}"},
{"1rP3rP2rP6rP4rP12rP8rP9rP"}, // A forward step on a stepper motor
{"6d133{1o484u0o484u}"},
{"_Hello World, and welcome to SIMPL_"},
{"5{ABC}"},
{" "},
{" "},
{" "},
{" "},
{" "},
{" "},
{"100m"}, // Time delay to see stepper motor action
};
int d = 5;
char name;
char* parray;
char buf[64];
char* addr;
//------------------------------------------------------------------------------
void setup()
{
Serial.begin(115200);
// Set up the various port lines for the ROMulator
// Data bus
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
// Bus control
pinMode(RAM_SEL,OUTPUT);
pinMode(READ,OUTPUT);
pinMode(WRITE,OUTPUT);
pinMode(TRISTATE,OUTPUT);
pinMode(IORQ,OUTPUT);
pinMode(RESET,OUTPUT);
// Shift register control
pinMode(loadPin, OUTPUT); // Set up the pins needed for the shift registers
pinMode(sclkPin, OUTPUT);
// pinMode(sinPin, INPUT);
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
digitalWrite(sclkPin,HIGH); // initialise the clock HIGH
x = 170; // Test data - alternate 1's and 0's
if(x>=128){digitalWrite(10,HIGH); x = x- 128;} else {digitalWrite(10,LOW);}
if(x>=64){digitalWrite(9,HIGH); x = x- 64;} else {digitalWrite(9,LOW);}
if(x>=32){digitalWrite(7,HIGH); x = x- 32;} else {digitalWrite(7,LOW);}
if(x>=16){digitalWrite(6,HIGH); x = x- 16;} else {digitalWrite(6,LOW);}
if(x>=8){digitalWrite(5,HIGH); x = x- 8;} else {digitalWrite(5,LOW);}
if(x>=4){digitalWrite(4,HIGH); x = x- 4;} else {digitalWrite(4,LOW);}
if(x>=2){digitalWrite(3,HIGH); x = x- 2;} else {digitalWrite(3,LOW);}
if(x>=1){digitalWrite(2,HIGH); x = x- 1;} else {digitalWrite(2,LOW);}
digitalWrite(READ,HIGH);
digitalWrite(WRITE,HIGH);
digitalWrite(RAM_SEL,HIGH);
Serial.println("Type H for Welcome or ? for Help");
parray = &array[0][0]; // parray is the pointer to the first element
}
// -----------------------------------------------------------------------------------------------------
void loop() // The SIMPL interpreter is just the following 3 functions executed within a loop
{
txtRead(buf, 64); // Get the next character from the buffer
txtChk(buf); // check if it is a colon definition
txtEval(buf); // Evaluate the character and execute the code associated with it
}
void txtRead (char *p, byte n) {
byte i = 0;
while (i < (n-1)) {
while (!Serial.available());
char ch = Serial.read();
if (ch == '\r' || ch == '\n') break;
if (ch >= ' ' && ch <= '~') {
*p++ = ch;
i++;
}
}
*p = 0;
}
void txtChk (char *buf) { // Check if the text starts with a colon and if so store in temp[]
if (*buf == ':') {
char ch;
int i =0;
while ((ch = *buf++)){
if (ch == ':') {
Serial.println(*buf); // get the name from the first character
name = *buf ;
buf++;
}
bufWrite((parray + (len*(name-65) +i)),*buf);
i++;
}
}
}
void txtEval (char *buf) {
unsigned int k = 0;
char *loop;
char ch;
while ((ch = *buf++)) {
switch (ch) {
case '0': // Ennumerate it to a variable x if the characters are digits
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
x = ch - '0';
while (*buf >= '0' && *buf <= '9') {
x = x*10 + (*buf++ - '0');
}
break;
case 'p': // Print out the value of x
Serial.println(x);
break;
case '=': // more familiar for maths
Serial.println(x);
break;
case 'd':
d = x;
break;
case 'A': // Point the interpreter to the array containing the words
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
case 'G':
case 'H':
case 'I':
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case 'Q':
case 'R':
case 'S':
case 'T':
case 'U':
case 'V':
case 'W':
case 'X':
case 'Y':
case 'Z':
name = ch - 65;
addr = parray + (len*name);
txtEval(addr);
break;
case ' ':
y = x;
case 'y':
y = x;
case '!': // store
y = x;
break;
case '@': // fetch
x = y;
break;
case '+': // Add
x = x+y;
break;
case '-': // Subtract
x = y-x;
break;
case '*': // Multiply
x = x*y;
break;
case '/': // Divide
x = y/x;
break;
case '?': // Print out all the RAM
parray = &array[0][0]; // reset parray to the pointer to the first element
for (int j = 0; j<26; j++) {
Serial.write(j+65); // print the caps word name
Serial.write(20); // space
for (int i=0; i<len; i++) {
bite = bufRead( parray + (j *len )+i); // read the array
Serial.write(bite); // print the character to the serial port
}
Serial.println();
}
for(int i = 0; i <11; i++) { // Print 12 free lines so it looks better on Arduino serial screen
Serial.println();
}
break;
case 'i':
x = digitalRead(d);
break;
case 'o':
digitalWrite(d, x%2);
break;
case 'm':
delay(x);
break;
case 'u':
delayMicroseconds(x);
break;
case '{':
k = x;
loop = buf;
while ((ch = *buf++) && ch != '}') {
}
case '}':
if (k) {
k--;
buf = loop;
}
break;
case 'k':
x = k;
break;
case '_':
while ((ch = *buf++) && ch != '_') {
Serial.print(ch);
}
Serial.println();
break;
case 's':
x = analogRead(x);
break;
case 'q': // Send an 8 bit byte to the shift register using shiftOut
PORTB &= ~_BV(0);
shiftOut(dataPin, clockPin, MSBFIRST, x); // shift out the bits:
PORTB |= _BV(0);
break;
case 'n':
// Output an 8 bit value on I/O Dig 2 - Dig 9
// Can be extended to 12 bits on Dig 2 - Dig 13
// Make D2 to D9 OUTPUTS
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
if(x>=128){digitalWrite(10,HIGH); x = x- 128;} else {digitalWrite(10,LOW);}
if(x>=64){digitalWrite(9,HIGH); x = x- 64;} else {digitalWrite(9,LOW);}
if(x>=32){digitalWrite(7,HIGH); x = x- 32;} else {digitalWrite(7,LOW);}
if(x>=16){digitalWrite(6,HIGH); x = x- 16;} else {digitalWrite(6,LOW);}
if(x>=8){digitalWrite(5,HIGH); x = x- 8;} else {digitalWrite(5,LOW);}
if(x>=4){digitalWrite(4,HIGH); x = x- 4;} else {digitalWrite(4,LOW);}
if(x>=2){digitalWrite(3,HIGH); x = x- 2;} else {digitalWrite(3,LOW);}
if(x>=1){digitalWrite(2,HIGH); x = x- 1;} else {digitalWrite(2,LOW);}
break;
//-------------------------------------------------------------------------------------------
case 'r': // read the value at the data port D2 - D10
// Set up the address - write the 16 bits to the address registers
PORTB &= ~_BV(0);
shiftOut(dataPin, clockPin, MSBFIRST, x>>8); // shift out the high bits:
shiftOut(dataPin, clockPin, MSBFIRST, x); // shift out the low bits:
PORTB |= _BV(0);
pinMode(2, INPUT) ;
pinMode(3, INPUT);
pinMode(4, INPUT);
pinMode(5, INPUT);
pinMode(6, INPUT);
pinMode(7, INPUT);
pinMode(9, INPUT);
pinMode(10, INPUT);
// Assert RAM_SEL
digitalWrite(RAM_SEL, LOW);
// Take the buffer out of tri-state
digitalWrite(TRISTATE,LOW);
// Assert READ
digitalWrite(READ, LOW);
// Get the data
x = 0;
if (digitalRead(2)){ x = x+1;}
if (digitalRead(3)){ x = x+2;}
if (digitalRead(4)){ x = x+4;}
if (digitalRead(5)){ x = x+8;}
if (digitalRead(6)){ x = x+16;}
if (digitalRead(7)){ x = x+32;}
if (digitalRead(9)){ x = x+64;}
if (digitalRead(10)){ x = x+128;}
// delay(100);
digitalWrite(READ, HIGH);
digitalWrite(RAM_SEL, HIGH); // Deselect the RAM
digitalWrite(TRISTATE,HIGH); // Put the buffer into tri-state
Serial.println(x);
break;
//----------------------------------------------------------------------
// Send an 16 bit byte to the shift register using shiftOut
case 'w':
// Write Cycle
// Connect DIR to /WR as a write cycle is from B to A and a read is from A to B
// Set up the address - write the 16 bits to the address registers
PORTB &= ~_BV(0);
shiftOut(dataPin, clockPin, MSBFIRST, x>>8); // shift out the high bits:
shiftOut(dataPin, clockPin, MSBFIRST, x); // shift out the low bits:
PORTB |= _BV(0);
x = y; // get the data byte
// Assert WRITE - sets the direction of the bi-directional buffer
digitalWrite(WRITE, LOW);
// Take the buffer out of tri-state
digitalWrite(TRISTATE,LOW);
// Set up the data - output the 8 bits D0-D7 on Digital pins D2-D9
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
if(x>=128){digitalWrite(10,HIGH); x = x- 128;} else {digitalWrite(10,LOW);}
if(x>=64){digitalWrite(9,HIGH); x = x- 64;} else {digitalWrite(9,LOW);}
if(x>=32){digitalWrite(7,HIGH); x = x- 32;} else {digitalWrite(7,LOW);}
if(x>=16){digitalWrite(6,HIGH); x = x- 16;} else {digitalWrite(6,LOW);}
if(x>=8){digitalWrite(5,HIGH); x = x- 8;} else {digitalWrite(5,LOW);}
if(x>=4){digitalWrite(4,HIGH); x = x- 4;} else {digitalWrite(4,LOW);}
if(x>=2){digitalWrite(3,HIGH); x = x- 2;} else {digitalWrite(3,LOW);}
if(x>=1){digitalWrite(2,HIGH); x = x- 1;} else {digitalWrite(2,LOW);}
// Select the RAM
// Assert RAM_SEL
digitalWrite(RAM_SEL, LOW);
// Send the data
// delay(100);
// Assert /WR
// Deselct RAM
digitalWrite(RAM_SEL,HIGH);
// De-assert /WR
digitalWrite(WRITE, HIGH);
// Put the buffer into tri-state
digitalWrite(TRISTATE,HIGH);
break;
// Tristate registers and data buffer
// Read Cycle
// Set up the address
// Set up the data
// Select the RAM
// Assert /RD
// Read the data from the port into memory
// De-assert /RD
// Deselct RAM
// Tristate registers and data buffer
// PORTB &= ~_BV(0);
// shiftOut(dataPin, clockPin, MSBFIRST, x>>8); // shift out the high bits:
// shiftOut(dataPin, clockPin, MSBFIRST, x); // shift out the low bits:
// PORTB |= _BV(0);
// break;
case 't': // test the inputs from 74HC165 shift registers
// Read incoming word from 74HC165
digitalWrite(loadPin, LOW);
digitalWrite(loadPin, HIGH);
x = shiftIn(sinPin, sclkPin, MSBFIRST);
digitalWrite(sclkPin,HIGH);
break;
}
}
}
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