82C55A Просмотр технического описания (PDF) - Intersil

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производитель

82C55A

CMOS Programmable Peripheral Interface

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CONTROL WORD

D7 D6 D5 D4 D3 D2 D1 D0

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1/0 1/0 1/0

82C55A

PC2-PC0

1 = INPUT

0 = OUTPUT

PORT B

1 = INPUT

0 = OUTPUT

WR

GROUP B MODE

0 = MODE 0

1 = MODE 1

RD

FIGURE 11. MODE CONTROL WORD

PC3

INTRA

PA7-PA0 8

PC7

INTE

1

PC6

OBFA

ACKA

INTE

2

PC4

PC5

STBA

IBFA

PC2-PC0 3 I/O

FIGURE 12. MODE 2

DATA FROM

CPU TO 82C55A

WR

OBF

INTR

ACK

STB

tWOB

tST

tAOB

tAK

IBF

PERIPHERAL

BUS

tSIB

tPS

tPH

tAD

tKD

tRIB

RD

DATA FROM

DATA FROM

PERIPHERAL TO 82C55A

82C55A TO PERIPHERAL

DATA FROM

82C55A TO CPU

NOTE: Any sequence where WR occurs before ACK and STB occurs before RD is permissible. (INTR = IBF • MASK • STB • RD ÷ OBF •

MASK • ACK • WR)

FIGURE 13. MODE 2 (BI-DIRECTIONAL)

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