mirror of https://github.com/jscrane/r65emu.git
92 lines
1.6 KiB
C++
92 lines
1.6 KiB
C++
#include <Arduino.h>
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#include "ps2drv.h"
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#if !defined(KBD_BUFFER)
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#define KBD_BUFFER 16
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#endif
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static volatile uint8_t buffer[KBD_BUFFER];
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static volatile uint8_t head, tail;
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static uint8_t DataPin;
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// The ISR for the external interrupt
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#if defined(ESP32) || defined(ESP8266)
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IRAM_ATTR
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#endif
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void ps2interrupt(void)
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{
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static uint8_t bitcount=0;
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static uint8_t incoming=0;
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static uint32_t prev_ms=0;
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uint32_t now_ms;
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uint8_t n, val;
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val = digitalRead(DataPin);
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now_ms = millis();
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if (now_ms - prev_ms > 250) {
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bitcount = 0;
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incoming = 0;
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}
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prev_ms = now_ms;
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n = bitcount - 1;
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if (n <= 7) {
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incoming |= (val << n);
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}
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bitcount++;
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if (bitcount == 11) {
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uint8_t i = head + 1;
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if (i == KBD_BUFFER) i = 0;
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if (i != tail) {
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buffer[i] = incoming;
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head = i;
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}
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bitcount = 0;
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incoming = 0;
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}
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}
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bool PS2Driver::available() {
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if (head == tail)
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return false;
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uint8_t i = tail+1;
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if (i == KBD_BUFFER) i = 0;
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if (buffer[i] == 0xf0)
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return i != head;
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return true;
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}
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unsigned PS2Driver::read2() {
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if (head == tail)
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return 0;
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uint8_t i = tail+1;
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if (i == KBD_BUFFER) i = 0;
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tail = i;
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if (buffer[i] != 0xf0)
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return buffer[i];
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return 0xf000 | read2();
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}
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unsigned PS2Driver::peek() {
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if (head == tail)
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return 0;
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uint8_t i = tail+1;
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if (i == KBD_BUFFER) i = 0;
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if (buffer[i] == 0xf0) {
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if (++i == KBD_BUFFER) i = 0;
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return 0xf000 | buffer[i];
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}
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return buffer[i];
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}
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void PS2Driver::begin(uint8_t data_pin, uint8_t irq_pin)
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{
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DataPin = data_pin;
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pinMode(irq_pin, INPUT_PULLUP);
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pinMode(data_pin, INPUT_PULLUP);
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attachInterrupt(irq_pin, ps2interrupt, FALLING);
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head = tail = 0;
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}
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