RC6502-Apple-1-Replica/RC6502 Serial IO/pia_communicator/pia_communicator.ino

178 lines
3.4 KiB
C++

#include <SPI.h>
#include <MCP23S17.h>
#define DEBUG 0
#define KBD_INTERRUPT_ENABLE true
#define KBD_SEND_TIMEOUT 23
#define IO_SS 10
#define IO_VIDEO 0
#define IO_VIDEO_D0 0
#define IO_VIDEO_D6 6
#define VIDEO_RDA 5
#define VIDEO_DA 3
#define IO_KBD 1
#define IO_KBD_D0 8
#define IO_KBD_D6 14
#define IO_KBD_DA 15
#define KBD_READY 2
#define KBD_STROBE 4
MCP23S17 bridge(&SPI, IO_SS, 0);
void setup() {
Serial.begin(115200);
configure_pins();
configure_bridge();
output_status();
}
void configure_pins() {
pinMode(KBD_READY, INPUT);
pinMode(VIDEO_DA, INPUT);
pinMode(KBD_STROBE, OUTPUT);
pinMode(VIDEO_RDA, OUTPUT);
}
void configure_bridge() {
bridge.begin();
/* Configure video section */
for (int i = IO_VIDEO_D0; i <= IO_VIDEO_D6; i++) {
bridge.pinMode(i, INPUT);
}
bridge.pinMode(7, INPUT_PULLUP);
/* Configure keyboard section */
for (int i = 8; i <= 15; i++) {
bridge.pinMode(i, OUTPUT);
}
}
void output_status() {
Serial.println("RC6502 Apple 1 Replica");
debug_value("Video DA", digitalRead(VIDEO_DA));
debug_value("Video D0-D6", bridge.readPort(IO_VIDEO) & 127);
debug_value("Keyboard RDY", digitalRead(KBD_READY));
}
void debug_value(String description, byte value) {
debug_value(description, value, 1);
}
void debug_value(String description, byte value, int level) {
if (DEBUG < level) return;
Serial.print(description);
Serial.print(": ");
print_hex(value);
}
void print_hex(byte value) {
print_hex(value, true);
}
void print_hex(byte value, bool newline) {
if (value <= 0xF) {
Serial.print("0x0");
} else {
Serial.print("0x");
}
if (newline) Serial.println(value, HEX);
else Serial.print(value, HEX);
}
void serial_receive() {
if (Serial.available() > 0) {
int c = Serial.read();
debug_value("PIA RX", c, 10);
pia_send(c);
}
}
void pia_send(int c) {
/* Make sure STROBE signal is off */
digitalWrite(KBD_STROBE, LOW);
c = map_to_ascii(c);
/* Output the actual keys as long as it's supported */
if (c < 96) {
bridge.writePort(IO_KBD, c | 128);
digitalWrite(KBD_STROBE, HIGH);
if (KBD_INTERRUPT_ENABLE) {
byte timeout;
/* Wait for KBD_READY (CA2) to go HIGH */
timeout = KBD_SEND_TIMEOUT;
while(digitalRead(KBD_READY) != HIGH) {
delay(1);
if (timeout == 0) break;
else timeout--;
}
digitalWrite(KBD_STROBE, LOW);
/* Wait for KBD_READY (CA2) to go LOW */
timeout = KBD_SEND_TIMEOUT;
while(digitalRead(KBD_READY) != LOW) {
delay(1);
if (timeout == 0) break;
else timeout--;
}
} else {
delay(KBD_SEND_TIMEOUT);
digitalWrite(KBD_STROBE, LOW);
}
}
}
char map_to_ascii(int c) {
/* Convert ESC key */
if (c == 203) {
c = 27;
}
/* Ctrl A-Z */
if (c > 576 && c < 603) {
c -= 576;
}
/* Convert lowercase keys to UPPERCASE */
if (c > 96 && c < 123) {
c -= 32;
}
return c;
}
void serial_transmit() {
digitalWrite(VIDEO_RDA, HIGH);
if (digitalRead(VIDEO_DA) == HIGH) {
char c = bridge.readPort(IO_VIDEO) & 127;
debug_value("PIA TX", c, 10);
digitalWrite(VIDEO_RDA, LOW);
delay(12);
send_ascii(c);
}
}
char send_ascii(char c) {
if (DEBUG >= 5) Serial.print("[");
switch (c) {
case 0x0d: Serial.println(); /* Replace CR with LF */
default:
Serial.print(c);
}
if (DEBUG >= 5) Serial.print("]");
}
void loop() {
serial_receive();
serial_transmit();
}