Real Time Devices AD1200 User Manual page 91

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82C54
Table 1. Pln Descrlption
Symbol
Pln Number
Type Function
DIP PLCC
Dz-Do
1 - 8
2-9
vo
Data: Bidirectionaltri-state data bus lines,
connected to system data bus.
CLK O
9
1 0 Clock 0: Clock input of Counter 0.
OUT O 1 0 12
o
Output 0: Output of Counter 0.
GATE O 1 1
1 3
Gate 0: Gate input of Counter 0.
G N D 1 2
1 4
Ground: Power supply connection.
OUT 1
1 3
1 6
o
Out 1: Outpui of Counter 1
GATE 1
1 4 1 7
Gate 1: Gate inout of Counter 1.
CLK 1 1 5
1 8
Clock 1: Clock input of Counter 1.
GATE 2 1 6 t 9 I
Gate 2: Gate input of Counter 2.
OUT 2
1 7
20
o
Out 2: Output of Gounter 2.
CLK 2
1 8
21 I
Clock 2: Clock inout of Counter 2.
Ar, Ao 20-19 23-22 Address: Used to select one of the three Gounters
or the Control Word Register for read or write
operations. Normally connected to the system
address bus.
Ar
Ao
Selects
0
0
1
1
0
1
0
1
Counter 0
Counter 1
Counter 2
ControlWord Reqister
G
z',|,
24 I Chip Select A low on this input enables the 82C54
to respond to FD and WFi signals. RD and WFlare
iqnored otherwise.
m
22 26
I
Read Control: This input is low during CPU read
operations.
WF
23 27
I
Write Control: This input is low during GPU write
operations.
Vr:n
24
28
Power: * 5V power supplv connection.
NC
1 , 1 1 , 1 5 , 2 5
No Connect
FUNCTIONAL DESCRIPTION
General
The 82C54 is a programmable intervaltimer/counter
designed for use with Intel microcomputer systems.
It is a generalpurpose, multi-timing element that can
be treated as an anay ol llO ports in the system
software.
The 82C54 solves one o{ the most common prob-
lems in any microcomputer system, the generation
of accurate time delays under software control. In-
stead of setting up timing loops in software, the pro-
grammer configures the 82C54 to match his require-
ments and programs one of the counters for the de-
sired delay. After the desired delay, the 82C54 will
intenupt the CPU. Sottware overhead is minimal and
variable length delays can easily be accommodated.
Some of the other counter/timer functions common
to microcomputers which can be implemented with
the 82C54 are:
r Realtime clock
o Even counter
o Digital one-shot
o Programmable
rate generator
. Square wave generator
o BinaU rate multiplier
o Complex waveform generator
o Complex motor controller