adding VIA from PET

This commit is contained in:
steve 2023-10-03 15:25:53 +01:00
parent 2b31012100
commit fa8759415e
4 changed files with 382 additions and 2 deletions

17
line.h Normal file
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@ -0,0 +1,17 @@
#ifndef _LINE_H
#define _LINE_H
class Line {
public:
Line(): _state(false) {}
operator bool() { return _state; }
void set(bool state) { _state = state; }
void clear() { set(false); }
void set() { set(true); }
private:
volatile bool _state;
};
#endif

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@ -20,7 +20,7 @@ inline bool c2_high_to_low(uint8_t cr) { return !c2_low_to_high(cr); }
inline bool output_selected(uint8_t cr) { return cr & 0x04; }
void PIA::write(Memory::address a, uint8_t b) {
#if defined(DEBUGGING)
#if defined(DEBUG_PIA)
Serial.print(millis());
Serial.print(" > ");
Serial.print(a, 16);
@ -44,7 +44,7 @@ void PIA::write(Memory::address a, uint8_t b) {
}
uint8_t PIA::read(Memory::address a) {
#if defined(DEBUGGING)
#if defined(DEBUG_PIA)
Serial.print(millis());
Serial.print(" < ");
Serial.println(a, 16);

265
via.cpp Normal file
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@ -0,0 +1,265 @@
#include <Arduino.h>
#include <memory.h>
#include <line.h>
#include <via.h>
#define VPORTB 0x00
#define VPORTA 0x01
#define DDRB 0x02
#define DDRA 0x03
#define T1LO 0x04
#define T1HI 0x05
#define T1LLO 0x06
#define T1LHI 0x07
#define T2LO 0x08
#define T2HI 0x09
#define SHIFT 0x0a
#define ACR 0x0b
#define PCR 0x0c
#define IFR 0x0d
#define IER 0x0e
#define VPORTA_NH 0x0f
void VIA::write(Memory::address a, uint8_t b) {
switch (a & 0x0f) {
case VPORTB:
write_vportb(b);
break;
case VPORTA:
write_vporta(b);
break;
case DDRB:
write_vddrb(b);
break;
case DDRA:
write_vddra(b);
break;
case T1LO:
write_t1lo(b);
break;
case T1LLO:
write_t1llo(b);
break;
case T1HI:
write_t1hi(b);
break;
case T1LHI:
write_t1lhi(b);
break;
case T2LO:
write_t2lo(b);
break;
case T2HI:
write_t2hi(b);
break;
case SHIFT:
write_sr(b);
break;
case ACR:
write_acr(b);
break;
case PCR:
write_pcr(b);
break;
case IFR:
write_ifr(b);
break;
case IER:
write_ier(b);
break;
case VPORTA_NH:
write_vporta_nh(b);
break;
}
}
void VIA::write_vportb(uint8_t b) {
_portb = (b & _ddrb);
clear_int(INT_CB1_ACTIVE | INT_CB2_ACTIVE);
}
void VIA::write_vporta(uint8_t b) {
_porta = (b & _ddra);
clear_int(INT_CA1_ACTIVE | INT_CA2_ACTIVE);
}
void VIA::write_t1llo(uint8_t b) {
_t1_latch = (_t1_latch & 0xff00) | b;
}
void VIA::write_t1lhi(uint8_t b) {
_t1_latch = (_t1_latch & 0x00ff) | (b << 8);
clear_int(INT_TIMER1);
}
void VIA::write_t1hi(uint8_t b) {
_t1 = _t1_latch;
start_timer1();
clear_int(INT_TIMER1);
}
void VIA::write_t2lo(uint8_t b) {
_t2 = b;
_timer2 = false;
clear_int(INT_TIMER2);
}
void VIA::write_t2hi(uint8_t b) {
_t2 += (b << 8);
start_timer2();
clear_int(INT_TIMER2);
}
void VIA::write_sr(uint8_t b) {
_sr = b;
clear_int(INT_SR);
}
void VIA::write_pcr(uint8_t b) {
_pcr = b;
CA2.set(b & 0x02);
}
void VIA::write_acr(uint8_t b) {
_acr = b;
if (b & ACR_T1_CONTINUOUS)
start_timer1();
}
void VIA::write_ier(uint8_t b) {
if (b & INT_MASTER)
_ier |= b & 0x7f;
else
_ier &= ~(b & 0x7f);
}
void VIA::write_vporta_nh(uint8_t b) {
_porta = (b & _ddra);
}
uint8_t VIA::read(Memory::address a) {
switch (a & 0x0f) {
case VPORTB:
return read_vportb();
case VPORTA:
return read_vporta();
case DDRB:
return read_vddrb();
case DDRA:
return read_vddra();
case T1LO:
return read_t1lo();
case T1HI:
return read_t1hi();
case T1LLO:
return read_t1llo();
case T1LHI:
return read_t1lhi();
case T2LO:
return read_t2lo();
case T2HI:
return read_t2hi();
case SHIFT:
return read_sr();
case ACR:
return read_acr();
case PCR:
return read_pcr();
case IFR:
return read_ifr();
case IER:
return read_ier();
case VPORTA_NH:
return read_vporta_nh();
}
return 0x00;
}
uint8_t VIA::read_vportb() {
return (_portb & _ddrb) | ~_ddrb;
}
uint8_t VIA::read_vporta() {
return (_porta & _ddra) | ~_ddra;
}
uint8_t VIA::read_t1lo() {
clear_int(INT_TIMER1);
return _t1 & 0xff;
}
uint8_t VIA::read_t2lo() {
clear_int(INT_TIMER2);
return _t2 & 0xff;
}
uint8_t VIA::read_sr() {
clear_int(INT_SR);
return _sr;
}
uint8_t VIA::read_vporta_nh() {
return (_porta & _ddra) | ~_ddra;
}
void VIA::tick() {
uint32_t now = millis();
if (_timer1) {
uint32_t interval = now - _t1_tick;
if (_t1 < interval) {
_t1 = 0;
_timer1 = false;
set_int(INT_TIMER1);
} else {
_t1 -= interval;
_t1_tick = now;
}
}
if (_timer2) {
uint32_t interval = now - _t1_tick;
if (_t2 < interval) {
_t2 = 0;
_timer2 = false;
set_int(INT_TIMER2);
} else {
_t2 -= interval;
_t2_tick = now;
}
}
}
void VIA::set_int(uint8_t i) {
_ifr |= i;
if ((_ier & INT_MASTER) && (_ier & i))
set_interrupt();
}
void VIA::clear_int(uint8_t i) {
_ifr &= ~i;
}
void VIA::write_vporta_in_bit(uint8_t bit, bool state) {
if (state)
_porta |= bit;
else
_porta &= ~bit;
}
void VIA::write_vportb_in_bit(uint8_t bit, bool state) {
if (state)
_portb |= bit;
else
_portb &= ~bit;
}
void VIA::start_timer1() {
_t1_tick = millis();
_timer1 = true;
}
void VIA::start_timer2() {
_t2_tick = millis();
_timer2 = true;
}

98
via.h Normal file
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#ifndef _VIA_H
#define _VIA_H
class VIA {
public:
VIA(): _irq(0), _timer1(false), _timer2(false), _t1(0), _t2(0), _t1_latch(0),
_sr(0), _acr(0), _pcr(0), _ier(0), _ifr(0), _ddra(0), _ddrb(0), _porta(0), _portb(0) {}
virtual void reset() {
_timer1 = _timer2 = false;
_t1 = _t2 = _t1_latch = 0;
_sr = _acr = _pcr = _ier = _ifr = _porta = _portb = _ddra = _ddrb = 0;
}
void write(Memory::address, uint8_t);
uint8_t read(Memory::address);
void write_vporta_in_bit(uint8_t, bool);
void write_vportb_in_bit(uint8_t, bool);
void tick();
Line CA2;
void register_irq(Line &irq) { _irq = &irq; }
// acr
static const uint8_t ACR_SHIFT_MASK = 0x1c;
static const uint8_t ACR_T1_SET_PB7 = 0x80;
static const uint8_t ACR_T1_CONTINUOUS = 0x40;
static const uint8_t ACR_T2_COUNT_PB6 = 0x20;
static const uint8_t ACR_SO_T2_RATE = 0x10;
// ier and ifr bits
static const uint8_t INT_MASTER = 0x80;
static const uint8_t INT_TIMER1 = 0x40;
static const uint8_t INT_TIMER2 = 0x20;
static const uint8_t INT_CB1_ACTIVE = 0x10;
static const uint8_t INT_CB2_ACTIVE = 0x08;
static const uint8_t INT_SR = 0x04;
static const uint8_t INT_CA1_ACTIVE = 0x02;
static const uint8_t INT_CA2_ACTIVE = 0x01;
protected:
virtual void write_vportb(uint8_t);
virtual void write_vporta(uint8_t);
virtual void write_vddrb(uint8_t b) { _ddrb = b; }
virtual void write_vddra(uint8_t b) { _ddra = b; }
virtual void write_t1lo(uint8_t b) { write_t1llo(b); }
virtual void write_t1hi(uint8_t);
virtual void write_t1llo(uint8_t);
virtual void write_t1lhi(uint8_t);
virtual void write_t2lo(uint8_t);
virtual void write_t2hi(uint8_t);
virtual void write_sr(uint8_t);
virtual void write_acr(uint8_t b);
virtual void write_pcr(uint8_t b);
virtual void write_ifr(uint8_t b) { _ifr &= ~b; }
virtual void write_ier(uint8_t);
virtual void write_vporta_nh(uint8_t);
virtual uint8_t read_vportb();
virtual uint8_t read_vporta();
virtual uint8_t read_vddrb() { return _ddrb; }
virtual uint8_t read_vddra() { return _ddra; }
virtual uint8_t read_t1lo();
virtual uint8_t read_t1hi() { return _t1 / 0xff; }
virtual uint8_t read_t1llo() { return _t1_latch & 0xff; }
virtual uint8_t read_t1lhi() { return _t1_latch / 0xff; }
virtual uint8_t read_t2lo();
virtual uint8_t read_t2hi() { return _t2 / 0xff; }
virtual uint8_t read_sr();
virtual uint8_t read_acr() { return _acr; }
virtual uint8_t read_pcr() { return _pcr; }
virtual uint8_t read_ifr() { return _ifr; }
virtual uint8_t read_ier() { return _ier | 0x80; }
virtual uint8_t read_vporta_nh();
void set_interrupt() { if (_irq) _irq->set(); }
private:
Line *_irq;
void set_int(uint8_t);
void clear_int(uint8_t);
void start_timer1();
void start_timer2();
volatile bool _timer1, _timer2;
volatile uint16_t _t1, _t2;
uint16_t _t1_latch;
volatile uint32_t _t1_tick, _t2_tick;
uint8_t _sr, _acr, _pcr, _ier, _ifr, _ddra, _ddrb;
volatile uint8_t _porta, _portb;
};
#endif