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Parallel Ports
7-8
MC68328 DRAGONBALL PROCESSOR USER’S MANUAL
MOTOROLA
7.1.6 Port E
Port E is multiplexed with 7 chip-select signals that are identified below.
All 8 bits are implemented in the registers, but only bits 7-1 connect to the outside. As with
other ports, each bit can be individually configured, as needed. The programmer’s model for
port E is shown below.
DIRECTION- DIR[7:0]
These bits control the pin directions. While high, the pins are outputs; while low, the pins
are inputs. These bits reset to 0 and have no function while the SELECT bits are low.
DATA- D[7:0]
These bits control or report the data on the pins while the associated SELECT bits are
high. While the DIRECTION bits are high (output), D[7:0] controls the data to the pins.
While the DIRECTION bits are low (input), D[7:0] reports the signal level on the pins. The
data bits may be written at any time. Bits that are configured as inputs will accept the data
but the written data will not be accessible until their respective pins are configured as out-
Table 7-2. Port E Bit Functions
Bit
Port Function Other Function
0
none
none
1
Bit 1
CSA1
2
Bit 2
CSA2
3
Bit 3
CSA3
4
Bit 4
CSB0
5
Bit 5
CSB1
6
Bit 6
CSB2
7
Bit 7
CSB3
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DIRECTION
DATA
DIR7
DIR6
DIR5
DIR4
DIR3
DIR2
DIR1
DIR0
D7
D6
D5
D4
D3
D2
D1
D0
Address: $FFFFF420
Reset Value: $0000
Figure 7-14. Port E Data/Direction Register
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PULLUP
SELECT
PU7
PU6
PU5
PU4
PU3
PU2
PU1
PU0
SEL7
SEL6
SEL5
SEL4
SEL3
SEL2
SEL1
SEL0
Address: $FFFFF422
Reset Value: $8080
Figure 7-15. Port E Select Register
Содержание DragonBall MC68328
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Страница 103: ...Parallel Ports 7 16 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 117: ...UART 8 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 127: ...SPI Master 10 6 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Страница 137: ...Electrical Characteristics PRELIMINARY MOTOROLA MC68328 DRAGONBALL PROCESSOR USER S MANUAL 13 4 ...