Classic Apple Hardware that I recently acquired

( CLICK Here John Bell Engineering Analog Card for Apple ][.... Full Size for BIGGER PICTURE )

The ADC0817 is an Analog to Digital converter to allow the Apple to sense an Analog Value from a Device and Convert it to a Digital Value for Processing It.. An Example of one such Device would be a Thermistor, or Temperature Resistor, which changes Resistance with the Change in Temperature.

NS ADC0816/ADC0817 Data Sheet, JUL-1999

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( CLICK Here John Bell Engineering Digital I/O Card for Apple ][.... Full Size for BIGGER PICTURE )

The MOS6522 can be used as a Digital Input or Output Device, with Two 8-Bit Port per chip. The John Bell Card has Two MOS6522s, so 32 Individual Bits can be Read or Controlled. The Four, 16 Pin DIP Sockets are used for the 6522's I/O.

The MOS6522 is also used on the Mocking Board and the Echo+ Card.

John Bell Engineering's Apple II Parallel Interface Board Manual ( Local Copy )
John Bell Engineering's Apple II Parallel Interface Board Review ( MAR-1982 Byte Magazine ) ( Local Copy )
MOS MCS6522 Versatile Interface Adapter (VIA) Preliminary Data Sheet, NOV-1977
Rockwell R6522 Versatile Interface Adapter (VIA)
TI SN74LS05, Hex Inverters with Open-Collector Outputs

( CLICK Here John Bell Engineering Digital I/O Cards for Apple ][.... Full Size for BIGGER PICTURE )

John Bell 6522 Board, 74LS05 Circuit: This creates a Phase 2 Clock Signal from delaying the Phase 0 Clock Signal and give the 6522's different Addresses.

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Alternate 6522 Interfacing, from Apple Computer ( Local Copy )
Fairchild DM74LS74, Dual Positive-Edge-Triggered D Flip-Flops with Preset, Clear and Complementary Outputs
TI SN74LS05, 3-STATE Octal Bus Transceiver ( 8304 Replacment )

Apple Interfacing, from The Blacksburg Group ( Local Copy )