Table 4-17 Module Pin Functions
Module
Pin Mnemonic
DSI/IFETCH
DSO/IPIPE
Function
DSI/IFETCH
DSO/IPIPE
CPU32
BKPT/DSCLK
PGP7/IC4/OC5
PGP[6:3]/OC[4:1]
PGP[2:0]/IC[3:1]
PAI
BKPT/DSCLK
Discrete Input
Discrete Input
Discrete Input
Discrete Input
Discrete Input
Discrete Output
Discrete Input
Discrete Input
Discrete Input
Discrete Input
Discrete Input
Discrete Input
RXD
GPT
PCLK
PWMA, PWMB
PQS7/TXD
QSM
PQS[6:4]/PCS[3:1]
PQS3/PCS0/SS
PQS2/SCK
PQS1/MOSI
PQS0/MISO
RXD
4
4.6.5 Pin State During Reset
It is important to keep the distinction between pin function and pin electrical state clear.
Although control register values and mode select inputs determine pin function, a pin
driver can be active, inactive or in high-impedance state while reset occurs. During
power-up reset, pin state is subject to the constraints discussed in 4.6.7 Power-On
Reset.
NOTE
Pins that are not used should either be configured as outputs, or (if
configured as inputs) pulled to the appropriate inactive state. This de-
creases additional I
ply level.
caused by digital inputs floating near mid-sup-
DD
4.6.5.1 Reset States of SIM Pins
Generally, while RESET is asserted, SIM pins either go to an inactive high-impedance
state or are driven to their inactive states. After RESET is released, mode selection
occurs, and reset exception processing begins. Pins configured as inputs during reset
become active high-impedance loads after RESET is released. Inputs must be driven
to the desired active state. Pull-up or pull-down circuitry may be necessary. Pins con-
figured as outputs begin to function after RESET is released. Table 4-18 is a summary
of SIM pin states during reset.
MC68331
SYSTEM INTEGRATION MODULE
MOTOROLA
4-41
USER’S MANUAL
MOTOROLA [ MOTOROLA ]
