EE 308 -- LAB 8
Additional Memory and Ports

This lab will add 32K of external memory, and two additional parallel I/O ports, to your board. The 32K memory will be located at addresses from $2000 to $9FFF. When operating in the expanded mode, the 68HC11 uses Ports B and C to provide addresses and data for external devices. In order to compensate for losing these two valuable ports, we will also add a Motorola 68B21 Peripheral Interface Adapter to provide two I/O ports similar to Port C of the 68HC11. These two ports and their control registers will be located at memory addresses $B000 to $B003.

The attached schematic shows the necessary wiring to complete the memory expansion. Also attached is a wiring list which tells you exactly which pins to wire together, and a layout diagram which shows you one way to place the parts on your board. The parts and tools needed to do the wiring will be distributed in lab this week. The wiring should be complete and ready to check during your laboratory of Monday March 17 or Wednesday March 19.

A few notes about the wiring:

Bill Rison, < >
Tue Feb 24 1997

© 1997, New Mexico Tech