Listed is a brand new board that will let you have a 32-bit bus for your Apple II or Apple IIe computers. This item requires you to assemble AND solder! 

This board provides you FOUR input ports and FOUR output ports, together making it a 32-bit I/O bus. You can read and write any individual input or output port at any given time. Although the VCC/GND pins are exposed, you should NEVER use the output ports to source a load. You should watch carefully the power drawn by all other expansion slots max. You should ONLY use this board as a 32-bit data BUS to receive and send data! You can use this board to interface your Apple II/IIe with the Arduino or modern microcontroller bus.

IF in doubt, please ask questions FIRST before buying

WHAT YOU GET:

YOU GET ONLY THE PCB BOARD -- EITHER GREEN OR RED, DEPENDING ON AVAILABILITY. The last two photos are as example ONLY! 


TERMS:
  • NO RETURNS/REFUND
  • NO TECHNICAL SUPPORT PROVIDED
IMPORTANT: 

The board is sold AS IS and ONLY the board.


BOM

  • IC1 - IC4 (the 74HCT245's) are for input ports 0 to 3, respectively.
  • IC5 - IC8 (the 74HCT374's) are for output ports 0 to 3, respectively.
  • All the capacitors are 0.1uF ceramic decoupling capacitors.
  • IC9 is the 74HCT138.
You MUST use the same logic family for all the ICs! Do NOT mix 74HCxxx with 74HCTxxx logic chips. Do NOT use the 74LSxxx logic chips. They are TOO old and sucks a lot of ampere! The best place to buy logic chips is digikey.com. eBay sellers tend to charge more expensive for logic chips than they actually shown has IC7 in the wrong direction, btw.)

HOW TO ACCESS THE PORTS

Once you have your board populated with the chips, you can test it out by plugging it into slot #4, which is typically is a good slot to use. Slots 5-7 should fine as well. Below is the information of the I/O addresses for each slot.

$C0F0-$C0FF Slot 7 I/O Memory Locations
$C0E0-$C0EF Slot 6 I/O Memory Locations
$C0D0-$C0DF Slot 5 I/O Memory Locations
$C0C0-$C0CF Slot 4 I/O Memory Locations
$C0B0-$C0BF Slot 3 I/O Memory Locations
$C0A0-$C0AF Slot 2 I/O Memory Locations
$C090-$C09F  Slot 1 I/O Memory Locations 

As an example, using slot #4, we know that the starting address is hex $C0C0, which is 49344 in decimal. That means: $C0C0 controls port zero for input or output of a byte. $C0C1 for port 1; $C0C2 for port 2; and $C0C3 for port 3. To test your board, you can use 8 female-female Dupont wires like how it shown in photos #2 and #3. You hook up the wires to one output port and two wires each to each of the four input ports. Then do the below from your Apple II/IIe computer.

Say you hook up to OUTPUT port zero, you do: POKE 49344, 255 // This will write a byte of value 255 to output port zero. With two wires connected to the two RIGHTMOST pins (bits 8 & 7) of each of the INPUT ports, you can read the values of each of the INPUT ports as follows:

PRINT PEEK(49344) // read PORT 0
PRINT PEEK(49345) // read PORT 1
PRINT PEEK(49346) // read PORT 2
PRINT PEEK(49347) // read PORT 3

The value read should be 192, which is the sum of bit 8 (128) + bit 7 (64).

You can then proceed to test other OUTPUT ports. Say, if you want OUTPUT port 1, then the address to POKE (write) is 49345. POKE 49345, 255

STANDARD DISCLAIMER:

I AM NOT RESPONSIBLE FOR YOUR PROJECT IN ANYWAY, THAT IS, ANY KIND OF DAMAGES TO YOUR MACHINE(S)/COMPUTER(S), INCLUDING BUT NOT LIMITED OF TO PHYSICAL, MENTAL, EMOTIONAL, PROPERTY-WISE, OR FINANCIALLY. NOR AM I RESPONSIBLE FOR ANY TECHNICAL SUPPORT. THIS IS JUST LIKE A BREAD BOARD THAT YOU USE WIH YOUR RESPONSIBILITY AND IMAGINATION. You MUST read and understand all the computer electrical characteristics on its peripherals, e.g., expansion slots, etc., before using the ampere you can use! Please research that on the internet! You MUST also understand all electrical characteristics of whatever ICs that you use. Read the datasheets! NO returns or refunds. Please note that the descriptions were provided to the best of quality. Not responsible for any typos.

PLEASE ASK QUESTIONS IF YOU'RE IN DOUBT BEFORE BIDDING OR BUYING!