Emulate the Brain Board II

README.md

@@ -29,6 +29,7 @@ Portable emulator of an Apple II+ or //e. Written in Go.
   - No Slot Clock based on the DS1216
   - Videx Videoterm 80 column card with the Videx Soft Video Switch (Apple ][+ only)
   - SwyftCard (Apple //e only)
+  - Brain Board II
 - Useful cards not emulating a real card
   - Bootable SmartPort / ProDOS card with the following smartport devices:
       - Block device (hard disks)
@@ -185,6 +186,8 @@ Only valid on SDL mode
 ### Command line options
 
 ```terminal
+  -brainBoardSlot int
+        slot for the Brain Board II. -1 for none (default -1)
   -charRom string
         rom file for the character generator (default "<default>")
   -consoleCardSlot int

apple2Setup.go

@@ -213,6 +213,11 @@ func (a *Apple2) AddSwyftCard() {
 	a.insertCard(c, 3)
 }
 
+// AddBrainBoardII inserts a Brain Board II card
+func (a *Apple2) AddBrainBoardII(slot int) {
+	a.insertCard(NewCardBrainBoardII(), slot)
+}
+
 // AddRGBCard inserts an RBG option to the Apple IIe 80 col 64KB card
 func (a *Apple2) AddRGBCard() {
 	setupRGBCard(a)

apple2main.go

@@ -80,6 +80,10 @@ func MainApple() *Apple2 {
 		"printer",
 		1,
 		"slot for the Parallel Printer Interface. -1 for none")
+	brainBoard := flag.Int(
+		"brainBoardSlot",
+		-1,
+		"slot for the Brain Board II. -1 for none")
 	ramWorksKb := flag.Int(
 		"ramworks",
 		8192,
@@ -278,6 +282,9 @@ func MainApple() *Apple2 {
 		}
 		a.AddSwyftCard()
 	}
+	if *brainBoard > 0 {
+		a.AddBrainBoardII(*brainBoard)
+	}
 
 	var trackTracer trackTracer
 	if *traceTracks {

cardBrainBoard2.go

@@ -0,0 +1,105 @@
+package izapple2
+
+/*
+	Brain board II card for Apple II
+
+See:
+	http://www.willegal.net/appleii/brainboard.htm
+	http://www.willegal.net/appleii/bb-v5_3.1.pdf
+	https://github.com/Alex-Kw/Brain-Board-II
+
+The Brain Board II card has 4 banks instead of the 2 of the
+original Brain Board:
+	Bank 0: SS clear, DIP2 OFF (wozaniam)
+	Bank 1: SS set, DIP2 OFF (applesoft)
+	Bank 2: SS clear, DIP2 ON (wozaniam)
+	Bank 3: SS set, DIP2 ON (integer)
+
+The card is emulated as having the DIP switches as follows:
+	1 - ON: The range F8 can be replaced
+	2 - ON: Select the two top banks
+	3 - OFF: The motherboard ROM is always replaced
+	4 - ON: The softswitch selects low or high bank
+
+Softswitches:
+	$COsO - SS clear: Low bank selected
+	$COs1 - SS set: High bank selected
+
+Operation:
+	The card boots on wozaniam. Use CAPS LOCK for the commands
+	to work. Starts with left arrow.
+	To siwtch to Integer BASIC, type:
+		1000:AD 91 C0 6C FC FF
+		R
+	To return to wozaniam, type:
+		CALL -151
+		1000:AD 90 C0 6C FD FF
+		1000G
+*/
+
+// CardBrainBoardII represents a Brain Board II card
+type CardBrainBoardII struct {
+	cardBase
+	highBank bool
+	dip2     bool
+	rom      []uint8
+}
+
+// NewCardBrainBoardII creates a new CardBrainBoardII
+func NewCardBrainBoardII() *CardBrainBoardII {
+	var c CardBrainBoardII
+	c.name = "Brain Board II"
+
+	c.highBank = false // Start with wozaniam by default
+	c.dip2 = true      // Use the wozaniam+integer banks
+
+	// The ROM has:xaa-wozaniam xab-applesoft xac-wozaniam xad-integer
+	data, _, err := LoadResource("<internal>/ApplesoftInteger.BIN")
+	if err != nil {
+		// The resource should be internal and never fail
+		panic(err)
+	}
+	c.rom = data
+
+	// The ROM of the card is paged as the rest of the ROMs
+	c.romCxxx = &c
+	return &c
+}
+
+func (c *CardBrainBoardII) assign(a *Apple2, slot int) {
+	c.addCardSoftSwitchRW(0, func() uint8 {
+		c.highBank = false
+		return 0x55
+	}, "BRAINCLEAR")
+
+	c.addCardSoftSwitchRW(1, func() uint8 {
+		c.highBank = true
+		return 0x55
+	}, "BRAINSET")
+
+	c.cardBase.assign(a, slot)
+	a.mmu.inhibitROM(c)
+}
+
+func (c *CardBrainBoardII) translateAddress(address uint16) uint16 {
+	translated := address - 0xc000
+	if c.highBank {
+		translated += 0x4000
+	}
+	if c.dip2 {
+		translated += 0x8000
+	}
+	return translated
+}
+
+func (c *CardBrainBoardII) peek(address uint16) uint8 {
+	return c.rom[c.translateAddress(address)]
+}
+
+func (c *CardBrainBoardII) poke(address uint16, value uint8) {
+	// Nothing
+}
+
+func (c *CardBrainBoardII) setBase(base uint16) {
+	// Nothing
+}