Datasheet

36 MC68331TS/D

The write to the port F data register is stored in the internal data latch, and if any port F pin is configured

as an output, the value stored for that bit is driven onto the pin. A read of the port F data register returns

the value at the pin only if the pin is configured as a discrete input. Otherwise, the value read is the value

stored in the register.

The port F data register is a single register that can be accessed in two locations. When accessed at

$YFFA19, the register is referred to as PORTF0; when accessed at $YFFA1B, the register is referred

to as PORTF1. The register can be read or written at any time. It is unaffected by reset.

The bits in this register control the direction of the pin drivers when the pins are configured for I/O. Any

bit in this register set to one configures the corresponding pin as an output. Any bit in this register

cleared to zero configures the corresponding pin as an input.

The bits in this register control the function of each port F pin. Any bit cleared to zero defines the corre-

sponding pin to be an I/O pin. Any bit set to one defines the corresponding pin to be an interrupt request

signal or MODCLK. The MODCLK signal has no function after reset.

Data bus pin 9 controls the state of this register following reset. If DATA9 is set to one during reset, the

zero during reset, this register is set to $00, defining all port F pins as I/O pins.

PORTF0, PORTF1 — Port F Data Register $YFFA19, $YFFA1B

15 8 7 6 5 4 3 2 1 0

NOT USED PF7 PF6 PF5 PF4 PF3 PF2 PF1 PF0

RESET:

U U U U U U U U

DDRF — Port F Data Direction Register $YFFA1D

15 8 7 6 5 4 3 2 1 0

NOT USED DDF7 DDF6 DDF5 DDF4 DDF3 DDF2 DDF1 DDF0

RESET:

0 0 0 0 0 0 0 0

PFPAR — Port F Pin Assignment Register $YFFA1F

15 8 7 6 5 4 3 2 1 0

NOT USED PFPA7 PFPA6 PFPA5 PFPA4 PFPA3 PFPA2 PFPA1 PFPA0

RESET:

DATA9 DATA9 DATA9 DATA9 DATA9 DATA9 DATA9 DATA9

Table 17 Port F Pin Assignments

PFPAR Field Port F Signal Alternate Signal

PFPA7 PF7 IRQ7

PFPA6 PF6 IRQ6

PFPA5 PF5 IRQ5

PFPA4 PF4 IRQ4

PFPA3 PF3 IRQ3

PFPA2 PF2 IRQ2

PFPA1 PF1 IRQ1

PFPA0 PF0 MODCLK

Freescale Semiconductor, I

Freescale Semiconductor, Inc.

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