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IN82C55 Datasheet, PDF (6/22 Pages) IK Semicon Co., Ltd – Compatible with all Intel and Most Other Microprocessors
IN82C55A
D7 D6 D5 D4 D3 D2 D1 D0
GROUP B
PORT C (LOWER)
1 = INPUT
0 = OUTPUT
PORT B
1 = INPUT
0 = OUTPUT
MODE SELECTION
0 = MODE 0
1 = MODE 1
GROUP B
PORT C (LOWER)
1 = INPUT
0 = OUTPUT
PORT B
1 = INPUT
0 = OUTPUT
MODE SELECTION
00 = MODE 0
01 = MODE 1
1X = MODE 2
MODE SET FLAG
1 = ACTIVE
Figure 6. Mode Definition Format
The mode definitions and possible mode combinations may seem confusing at first but after a cursory review of the
complete device operation a simple, logical I/O approach will surface. The design of the 82C55A has taken into
account things such as efficient PC board layout, control signal definition vs PC layout and complete functional
flexibility to support almost any peripheral device with no external logic. Such design represents the maximum use of
the available pins.
Single Bit Set/Reset Feature
Any of the eight bits of Port C can be Set or Reset using a single OUTput instruction. This feature reduces software
requirements in Control-based applications.
When Port C is being used as status/control for Port A or B, these bits can be set or reset by using the Bit Set/Reset
operation just as if they were data output ports.
D7 D6 D5 D4 D3 D2 D1 D0
DON’T
CARE
BIT SET/RESET
1 = SET
0 =RESET
BIT SELECT
01234567
0 1 0 1 0 1 0 1 B0
0 0 1 1 0 0 1 1 B1
0 0 0 0 1 1 1 1 B2
BIT SET/RESET FLAG
0 = ACTIVE
Figure 7. Bit Set/Reset Format
Rev. 00