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Trying optimizing terminal to stay under 600nS per clock cycle (not working ATM)

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Daniele Verducci su MatissePenguin 2020-11-29 12:19:55 +01:00
parent 4dcbfa8668
commit e79ed4fa86
1 changed files with 31 additions and 34 deletions
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65
arduino/arduino_terminal/arduino_terminal.ino
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@ -5,58 +5,55 @@
* 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
// EN 2 // Active low
// WR 11 // Active low
// DATA BUS IS: 3, 4, 5, 6, 7, 8, 9, 10;
byte incomingBuffer = 0; // Incoming from computer, to the Pat80
byte outgoingBuffer = 0; // Outgoing to computer, from the Pat80
void setup() {
Serial.begin(115200);
Serial.begin(2000000);
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);
DDRD = B00000010; // Port D (used arduino pins 2 (EN) and 3 to 7 (DATA)) is input. Avoid changing serial pins.
DDRB = B00000000; // Port B (used arduino pins 8 to 10 (DATA) and 11 (WR)) is input
attachInterrupt(digitalPinToInterrupt(2), onClk, CHANGE);
}
void loop() {}
void loop() {
if (Serial.available() > 0) {
incomingBuffer = Serial.read();
}
if (outgoingBuffer != 0) {
if ((outgoingBuffer >= 8 && outgoingBuffer <= 13) || (outgoingBuffer >= 32 && outgoingBuffer <= 127)) {
// Printable character
Serial.print((char)outgoingBuffer);
} else {
// Non-printable character
Serial.print("[0x");
Serial.print(outgoingBuffer, HEX);
Serial.print("]");
}
}
}
void onClk() {
if (digitalRead(EN)) {
if (PINB & B00000100 == B00000100) { // If EN is HIGH (clock pulse finished)
// 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)
// EN is LOW: Clock pulse started
if (PIND & B00001000 == B00001000) { // WR is HIGH (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;
PORTD = incomingBuffer << 3;
PORTB = incomingBuffer >> 5;
} 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("]");
}
outgoingBuffer = (PIND >> 3) | (PINB << 5); // Compose the final byte from the two parts
}
}
}