Freescale Semiconductor MC68332 - Pin State During Reset; Reset States of SIM Pins

SYSTEM INTEGRATION MODULE MC68332
4-42 USER’S MANUAL
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
DD
caused by digital inputs floating near mid-sup-
ply level.
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.
Table 4-17 Module Pin Functions
Module Pin Mnemonic Function
CPU32 DSI/IFETCH
DSI/IFETCH
DSO/IPIPE DSO/IPIPE
BKPT/DSCLK BKPT/DSCLK
GPT PGP7/IC4/OC5 Discrete Input
PGP[6:3]/OC[4:1] Discrete Input
PGP[2:0]/IC[3:1] Discrete Input
PAI Discrete Input
PCLK Discrete Input
PWMA, PWMB Discrete Output
QSM PQS7/TXD Discrete Input
PQS[6:4]/PCS[3:1] Discrete Input
PQS3/PCS0/SS
Discrete Input
PQS2/SCK Discrete Input
PQS1/MOSI Discrete Input
PQS0/MISO Discrete Input
RXD RXD
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