MC68332ACEH20 Datasheet, PDF (36/88 Pages) Freescale Semiconductor, Inc – 32-Bit Modular Microcontroller

Freescale Semiconductor, Inc.
AVEC — Autovector Enable
0 = External interrupt vector enabled
1 = Autovector enabled
This field selects one of two methods of acquiring the interrupt vector during the interrupt acknowledge
cycle. It is not usually used in conjunction with a chip-select pin.
If the chip select is configured to trigger on an interrupt acknowledge cycle (SPACE = 00) and the AVEC
field is set to one, the chip select automatically generates an AVEC in response to the interrupt cycle.
Otherwise, the vector must be supplied by the requesting device.
The AVEC bit must not be used in synchronous mode, as autovector response timing can vary because
of ECLK synchronization.
3.5.5 Port C Data Register
Bit values in port C determine the state of chip-select pins used for discrete output. When a pin is as-
signed as a discrete output, the value in this register appears at the output. This is a read/write register.
Bit 7 is not used. Writing to this bit has no effect, and it always returns zero when read.
PORTC — Port C Data Register
15
RESET:
NOT USED
$YFFA41
8
7
6
5
4
3
2
1
0
0
PC6 PC5 PC4 PC3 PC2 PC1 PC0
0
1
1
1
1
1
1
1
3.6 General-Purpose Input/Output
SIM pins can be configured as two general-purpose I/O ports, E and F. The following paragraphs de-
scribe registers that control the ports.
PORTE0, PORTE1 —Port E Data Register
$YFFA11, $YFFA13
15
RESET:
NOT USED
8
7
6
5
4
3
2
1
0
PE7 PE6 PE5 PE4 PE3 PE2 PE1 PE0
U
U
U
U
U
U
U
U
A write to the port E data register is stored in the internal data latch and, if any port E pin is configured
as an output, the value stored for that bit is driven on the pin. A read of the port E 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 E data register is a single register that can be accessed in two locations. When accessed at
$YFFA11, the register is referred to as PORTE0; when accessed at $YFFA13, the register is referred
to as PORTE1. The register can be read or written at any time. It is unaffected by reset.
DDRE — Port E Data Direction Register
$YFFA15
15
RESET:
NOT USED
8
7
6
5
4
3
2
1
0
DDE7 DDE6 DDE5 DDE4 DDE3 DDE2 DDE1 DDE0
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 as 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. This register can be read or written at any
time.
MOTOROLA
36
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