HS-82C55ARH Просмотр технического описания (PDF) - Intersil
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HS-82C55ARH Datasheet PDF : 17 Pages
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HS-82C55ARH
MODE DEFINITION SUMMARY
MODE 0
MODE 1
MODE 2
IN
OUT
IN
OUT
GROUP A ONLY
PA0
In
Out
In
Out
AP1
In
Out
In
Out
PA2
In
Out
In
Out
PA3
In
Out
In
Out
PA4
In
Out
In
Out
PA5
In
Out
In
Out
PA6
In
Out
In
Out
PA7
In
Out
In
Out
PB0
In
Out
In
Out
PB1
In
Out
In
Out
PB2
In
Out
In
Out
PB3
In
Out
In
Out
PB4
In
Out
In
Out
PB5
In
Out
In
Out
PB6
In
Out
In
Out
PB7
In
Out
In
Out
-
-
-
-
-
Mode 0 or
-
Mode 1 Only
-
-
PC0
In
PC1
In
PC2
In
PC3
In
PC4
In
PC5
In
PC6
In
PC7
In
Out
INTR B
INTR B
I/O
Out
IBF B
OBF B
I/O
Out
STB B
ACK B
I/O
Out
INTR A
INTR A
INTR A
Out
STB A
I/O
STB A
Out
IBF A
I/O
IBF A
Out
I/O
ACK A
ACK A
Out
I/O
OBF A
OBF A
Special Mode Combination Considerations
There are several combinations of modes possible. For any
combination, some or all of Port C lines are used for control
or status. The remaining bits are either inputs or outputs as
defined by a “Set Mode” command.
During a read of Port C, the state of all the Port C lines,
except the ACK and STB lines, will be placed on the data
bus. In place of the ACK and STB line states, flag status will
appear on the data bus in the PC2, PC4, and PC6 bit
positions as illustrated by Figure 25.
Through a “Write Port C” command, only the Port C pins
programmed as outputs in a Mode 0 group can be written.
No other pins can be affected by a “Write Port C” command,
nor can the interrupt enable flags be accessed. To write to
any Port C output programmed as an output in a Mode 1
group or to change an interrupt enable flag, the “Set/Reset
Port C Bit” command must be used.
With a “Set/Reset Port C Bit” command, any Port C line
programmed as an output (including IBF and OBF) can be
written, or an interrupt enable flag can be either set or reset.
Port C lines programmed as inputs, including ACK and STB
lines, associated with Port C fare not affected by a “Set/
Reset Port C Bit” command. Writing to the corresponding
Port C bit positions of the ACK and STB lines with the “Set/
Reset Port C Bit” command will affect the Group A and
Group B interrupt enable flags, as illustrated in Figure 25.
INPUT CONFIGURATION
D7 D6 D5 D4
D3
D2 D1 D0
I/O I/O IBFA INTEA INTRA INTEB IBFB INTRB
GROUP A
GROUP B
D7 D6
OBFA INTEA
OUTPUT CONFIGURATION
D5 D4
D3
D2 D1 D0
I/O I/O INTRA INTEB OBFB INTRB
GROUP A
GROUP B
FIGURE 23. MODE 1 STATUS WORD FORMAT
D7
D6
D5
D4
D3 D2 D1 D0
OBFA INTE1 IBFA INTE2 INTRA X
X
X
GROUP A
GROUP B
NOTE: (Defined by Mode 0 or Mode 1 Selection)
FIGURE 24. MODE 2 STATUS WORD FORMAT
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