MC68331CEH16 Datasheet, PDF (36/84 Pages) Freescale Semiconductor, Inc – 32-Bit Modular Microcontroller

Freescale Semiconductor, Inc.
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
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.
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
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.
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
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.
Table 17 Port F Pin Assignments
PFPAR Field
PFPA7
PFPA6
PFPA5
PFPA4
PFPA3
PFPA2
PFPA1
PFPA0
Port F Signal
PF7
PF6
PF5
PF4
PF3
PF2
PF1
PF0
Alternate Signal
IRQ7
IRQ6
IRQ5
IRQ4
IRQ3
IRQ2
IRQ1
MODCLK
Data bus pin 9 controls the state of this register following reset. If DATA9 is set to one during reset, the
register is set to $FF, which defines all port F pins as interrupt request inputs. If DATA9 is cleared to
zero during reset, this register is set to $00, defining all port F pins as I/O pins.
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