izapple2/cardDisk2.go
2022-10-24 23:09:06 +02:00

232 lines
5.5 KiB
Go

package izapple2
import (
"fmt"
"strconv"
"github.com/ivanizag/izapple2/storage"
)
/*
https://applesaucefdc.com/woz/reference2/
Good explanation of the softswitches and the phases:
http://yesterbits.com/media/pubs/AppleOrchard/articles/disk-ii-part-1-1983-apr.pdf
"IMW Floppy Disk I/O Controller info" (https://www.brutaldeluxe.fr/documentation/iwm/apple2_IWM_INFO_19840510.pdf)
"Understanfing the Apple II, chapter 9"
35 tracks, 16 sectors, 256 bytes
NIB: 35 tracks 6656 bytes, 232960 bytes
*/
// CardDisk2 is a DiskII interface card
type CardDisk2 struct {
cardBase
selected int // q5, Only 0 and 1 supported
power bool // q4
drive [2]cardDisk2Drive
dataLatch uint8
q6 bool
q7 bool
trackTracer trackTracer
}
type cardDisk2Drive struct {
name string
diskette storage.Diskette
phases uint8 // q3, q2, q1 and q0 with q0 on the LSB. Magnets that are active on the stepper motor
trackStep int // Stepmotor for tracks position. 4 steps per track
}
// NewCardDisk2 creates a new CardDisk2
func NewCardDisk2(trackTracer trackTracer) *CardDisk2 {
var c CardDisk2
c.name = "Disk II"
c.trackTracer = trackTracer
c.loadRomFromResource("<internal>/DISK2.rom")
return &c
}
// GetInfo returns smartPort info
func (c *CardDisk2) GetInfo() map[string]string {
info := make(map[string]string)
info["rom"] = "16 sector"
info["power"] = strconv.FormatBool(c.power)
info["D1 name"] = c.drive[0].name
info["D1 track"] = strconv.FormatFloat(float64(c.drive[0].trackStep)/4, 'f', 2, 64)
info["D2 name"] = c.drive[1].name
info["D2 track"] = strconv.FormatFloat(float64(c.drive[1].trackStep)/4, 'f', 2, 64)
return info
}
func (c *CardDisk2) reset() {
// UtA2e 9-12, all switches forced to off
drive := &c.drive[c.selected]
drive.phases = 0 // q0, q1, q2, q3
c.softSwitchQ4(false) // q4
c.selected = 0 // q5
c.q6 = false
c.q7 = false
}
func (c *CardDisk2) assign(a *Apple2, slot int) {
// Q1, Q2, Q3 and Q4 phase control soft switches,
for i := uint8(0); i < 4; i++ {
phase := i
c.addCardSoftSwitchR(phase<<1, func() uint8 {
// Update magnets and position
drive := &c.drive[c.selected]
drive.phases &^= (1 << phase)
drive.trackStep = moveDriveStepper(drive.phases, drive.trackStep)
if c.trackTracer != nil {
c.trackTracer.traceTrack(drive.trackStep)
}
return c.dataLatch // All even addresses return the last dataLatch
}, fmt.Sprintf("PHASE%vOFF", phase))
c.addCardSoftSwitchR((phase<<1)+1, func() uint8 {
// Update magnets and position
drive := &c.drive[c.selected]
drive.phases |= (1 << phase)
drive.trackStep = moveDriveStepper(drive.phases, drive.trackStep)
if c.trackTracer != nil {
c.trackTracer.traceTrack(drive.trackStep)
}
return 0
}, fmt.Sprintf("PHASE%vON", phase))
}
// Q4, power switch
c.addCardSoftSwitchR(0x8, func() uint8 {
c.softSwitchQ4(false)
return c.dataLatch
}, "Q4DRIVEOFF")
c.addCardSoftSwitchR(0x9, func() uint8 {
c.softSwitchQ4(true)
return 0
}, "Q4DRIVEON")
// Q5, drive selecion
c.addCardSoftSwitchR(0xA, func() uint8 {
c.softSwitchQ5(0)
return c.dataLatch
}, "Q5SELECT1")
c.addCardSoftSwitchR(0xB, func() uint8 {
c.softSwitchQ5(1)
return 0
}, "Q5SELECT2")
// Q6, Q7
for i := uint8(0xC); i <= 0xF; i++ {
iCopy := i
c.addCardSoftSwitchR(iCopy, func() uint8 {
return c.softSwitchQ6Q7(iCopy, 0)
}, "Q6Q7")
c.addCardSoftSwitchW(iCopy, func(value uint8) {
c.softSwitchQ6Q7(iCopy, value)
}, "Q6Q7")
}
c.cardBase.assign(a, slot)
}
func (c *CardDisk2) softSwitchQ4(value bool) {
if !value && c.power {
// Turn off
c.power = false
c.a.ReleaseFastMode()
drive := &c.drive[c.selected]
if drive.diskette != nil {
drive.diskette.PowerOff(c.a.cpu.GetCycles())
}
} else if value && !c.power {
// Turn on
c.power = true
c.a.RequestFastMode()
drive := &c.drive[c.selected]
if drive.diskette != nil {
drive.diskette.PowerOn(c.a.cpu.GetCycles())
}
}
}
func (c *CardDisk2) softSwitchQ5(selected int) {
if c.power && c.selected != selected {
// Selected changed with power on, power goes to the other disk
if c.drive[c.selected].diskette != nil {
c.drive[c.selected].diskette.PowerOff(c.a.cpu.GetCycles())
}
if c.drive[selected].diskette != nil {
c.drive[selected].diskette.PowerOn(c.a.cpu.GetCycles())
}
}
c.selected = selected
}
// Q6: shift/load
// Q7: read/write
func (c *CardDisk2) softSwitchQ6Q7(index uint8, in uint8) uint8 {
switch index {
case 0xC: // Q6L
c.q6 = false
case 0xD: // Q6H
c.q6 = true
case 0xE: // Q7L
c.q7 = false
case 0xF: // Q7H
c.q7 = true
}
c.processQ6Q7(in)
if index&1 == 0 {
// All even addresses return the last dataLatch
return c.dataLatch
}
return 0
}
func (c *CardDisk2) processQ6Q7(in uint8) {
d := &c.drive[c.selected]
if d.diskette == nil {
return
}
if !c.q6 { // shift
if !c.q7 { // Q6L-Q7L: Read
c.dataLatch = d.diskette.Read(d.trackStep, c.a.cpu.GetCycles())
} else { // Q6L-Q7H: Write the dataLatch value to disk. Shift data out
d.diskette.Write(d.trackStep, c.dataLatch, c.a.cpu.GetCycles())
}
} else { // load
if !c.q7 { // Q6H-Q7L: Sense write protect / prewrite state
// Bit 7 of the control status register means write protected
c.dataLatch = 0 // Never write protected
} else { // Q6H-Q7H: Load data into the controller
c.dataLatch = in
}
}
/*
if c.dataLatch >= 0x80 {
fmt.Printf("Datalach: 0x%.2x in cycle %v\n", c.dataLatch, c.a.cpu.GetCycles())
}
*/
}
func (d *cardDisk2Drive) insertDiskette(name string, dt storage.Diskette) {
d.name = name
d.diskette = dt
}