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amiga_keyb.cpp
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amiga_keyb.cpp
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/*
* This is code from
* https://github.com/hkzlab/AVR-Experiments/tree/master/libs/amiga_keyb
*
* I just modified it.
*/
#include <Arduino.h>
#include "amiga_keyb.h"
#define AMI_KBDCODE_SELFTESTFAILED 0xFC
#define AMI_KBDCODE_INITKEYSTREAM 0xFD
#define AMI_KBDCODE_ENDKEYSTREAM 0xFE
#define AMI_KBDCODE_LOSTSYNC 0xF9
// INT1 on PIN3 (DATAPIN) for ACK, that is DATAPIN needs to be pin 3
#define DATAPIN 3
#define CLKPIN 4
#define RELEASE(pin) { pinMode(pin, INPUT); digitalWrite(pin, HIGH);}
#define SET(pin) { digitalWrite(pin, LOW); pinMode(pin, OUTPUT);}
#define BUFSIZE 16
static uint8_t head=0, tail=0;
static uint8_t buf[BUFSIZE];
static uint8_t lastcmd=0;
static volatile uint8_t synced = 1;
static unsigned long lastsyncattempt=0;
static inline void amikbd_kClock(void);
static inline void amikbd_kToggleData(uint8_t bit);
uint8_t amikbd_kSync(void);
ISR(INT1_vect) {
synced = 1;
EIMSK &= ~(1 << INT1); // Disable INT1
}
void amikbd_setup(void) {
/* Set all the lines to input and disable pull-up resistors!
* The line will be pulled high by the resistors (10K) inside the Amiga.
* When we want to pull a line to low, we simply set the pin to output.
*/
// Prepare KDAT port
RELEASE(CLKPIN);
RELEASE(DATAPIN);
// EICRA &= ~((1 << ISC10) | (1 << ISC11)); // Trigger interrupt at LOW LEVEL (INT1)
EICRA |= ((1 << ISC10) | (1 << ISC11)); // Trigger interrupt at RISING EDGE (INT1)
EIMSK &= ~(1 << INT1); // Disable INT1
EIFR |= (1 << INTF1); // Clear interrupt flag
}
// http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0177.html
void amikbd_init(void) {
amikbd_kSync();
// We should send the "test failed" code here, if any problem is detected
// Send initializate powerup key stream
amikbd_kSendCommand(AMI_KBDCODE_INITKEYSTREAM);
// Here we should send the keycodes for all the "pressed" keyboard keys...
// But I will simply suppose there is none
amikbd_kSendCommand(AMI_KBDCODE_ENDKEYSTREAM);
//amikbd_kSendCommand(0x35); // TODO: Check if this is really useless
}
// Clock the keyboard line
static inline void amikbd_kClock(void) {
delayMicroseconds(20);
SET(CLKPIN);
delayMicroseconds(20);
RELEASE(CLKPIN);
delayMicroseconds(20);
}
void amikbd_kReset(void) {
SET(CLKPIN);
delay(600);
RELEASE(CLKPIN);
}
static inline void amikbd_kToggleData(uint8_t bit) {
if (bit){
SET(DATAPIN);
} else {
RELEASE(DATAPIN);
}
amikbd_kClock();
}
// http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0173.html
void amikbd_transfer(uint8_t command) {
RELEASE(DATAPIN);
amikbd_kToggleData((command >> 6) & 1);
amikbd_kToggleData((command >> 5) & 1);
amikbd_kToggleData((command >> 4) & 1);
amikbd_kToggleData((command >> 3) & 1);
amikbd_kToggleData((command >> 2) & 1);
amikbd_kToggleData((command >> 1) & 1);
amikbd_kToggleData((command >> 0) & 1);
amikbd_kToggleData((command >> 7) & 1);
RELEASE(DATAPIN);
delayMicroseconds(10); // Allow short time to settle
lastsyncattempt = millis();
synced = 0;
// Wait for sync
EIMSK |= (1 << INT1); // Enable INT1
}
void amikbd_update(){
static uint8_t prevsync = 0;
if(synced == 0 && millis() - lastsyncattempt > 143){
amikbd_kClock();
lastsyncattempt = millis();
prevsync = 1;
} else if(synced) {
if(prevsync == 1) {
amikbd_transfer(AMI_KBDCODE_LOSTSYNC);
prevsync = 2;
} else if (prevsync == 2) {
amikbd_transfer(lastcmd);
prevsync = 0;
} else if (head != tail) {
lastcmd = buf[head];
head = (head+1) % BUFSIZE;
amikbd_transfer(lastcmd);
}
}
}
void amikbd_kSendCommand(uint8_t command) {
uint8_t t = (tail + 1) % BUFSIZE;
if (command == 0xFF || head == t){
return;
}
buf[tail] = command;
tail = t;
}