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1.3.2.2
M68HC908AB32 MCU
The MCU is an MC68HC908AB32 and is available in one package only:
•
The QFP package mounts in a clam-shell socket.
The on-board MCU (the test MCU) simulates and debugs the MCU's interface
to its peripherals and to other devices on the target board through a variety of
connections. Depending on the connection, the MCU is used in one of three
operating modes:
•
•
•
1.3.2.3
Clocks
The ABICS contains a 4.1952-MHz crystal oscillator. When the remote target
connection is made, the user may opt to feed the output from the ABICS
crystal (SP-OSC) to the external clock input (OSC1) of the ABICS via W5, a
2-pin shunt.
1.3.2.4
Board Reset
The ABICS includes two reset sources:
•
•
The host system resets the ICS by cycling power to most of the ICS circuitry,
including the POR circuit. RS-232 handshake line DTR is used for this
purpose.
The
RESET
drives its RESET pin low after encountering several different exception
conditions. W3 is provided to allow you to select whether the target system can
reset the MCU on the ABICS (jumper between pins 1 and 2) or whether the
target system receives a reset signal from the ABICS (jumper between pins 2
and 3).
M68ICS08ABUM/D
64-pin QFP
In the ICS socket for programming and simple simulation
In the socket and connected to the target for emulation
On the target for MON08 debug operation
An output from the POR (Power-On Reset) circuit via the host system
software
An internal reset exception operation of the processor
function of the ABICS is both an input and an output. The ABICS
CHAPTER 1 – INTRODUCTION
1-7
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