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CD82C54 Schematic ( PDF Datasheet ) - Intersil Corporation

Teilenummer CD82C54
Beschreibung CMOS Programmable Interval Timer
Hersteller Intersil Corporation
Logo Intersil Corporation Logo 




Gesamt 17 Seiten
CD82C54 Datasheet, Funktion
82C54
March 1997
CMOS Programmable Interval Timer
Features
Description
• 8MHz to 12MHz Clock Input Frequency
• Compatible with NMOS 8254
- Enhanced Version of NMOS 8253
• Three Independent 16-Bit Counters
• Six Programmable Counter Modes
• Status Read Back Command
• Binary or BCD Counting
• Fully TTL Compatible
• Single 5V Power Supply
• Low Power
- ICCSB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10µA
- ICCOP . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA at 8MHz
• Operating Temperature Ranges
- C82C54 . . . . . . . . . . . . . . . . . . . . . . . . . .0oC to +70oC
- I82C54 . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to +85oC
- M82C54 . . . . . . . . . . . . . . . . . . . . . . . -55oC to +125oC
The Intersil 82C54 is a high performance CMOS Program-
mable Interval Timer manufactured using an advanced 2
micron CMOS process.
The 82C54 has three independently programmable and
functional 16-bit counters, each capable of handling clock
input frequencies of up to 8MHz (82C54) or 10MHz
(82C54-10) or 12MHz (82C54-12).
The high speed and industry standard configuration of the
82C54 make it compatible with the Intersil 80C86, 80C88,
and 80C286 CMOS microprocessors along with many other
industry standard processors. Six programmable timer
modes allow the 82C54 to be used as an event counter,
elapsed time indicator, programmable one-shot, and many
other applications. Static CMOS circuit design insures low
power operation.
The Intersil advanced CMOS process results in a significant
reduction in power with performance equal to or greater than
existing equivalent products.
Pinouts
82C54 (PDIP, CERDIP, SOIC)
TOP VIEW
D7 1
D6 2
D5 3
D4 4
D3 5
D2 6
D1 7
D0 8
CLK 0 9
OUT 0 10
GATE 0 11
GND 12
24 VCC
23 WR
22 RD
21 CS
20 A1
19 A0
18 CLK 2
17 OUT 2
16 GATE 2
15 CLK 1
14 GATE 1
13 OUT 1
82C54 (PLCC/CLCC)
TOP VIEW
4 3 2 1 28 27 26
D4 5
D3 6
D2 7
D1 8
D0 9
CLK 0 10
NC 11
25 NC
24 CS
23 A1
22 A0
21 CLK2
20 OUT 2
19 GATE 2
12 13 14 15 16 17 18
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
http://www.intersil.com or 407-727-9207 | Copyright © Intersil Corporation 1999
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File Number 2970.1






CD82C54 Datasheet, Funktion
82C54
Possible Programming Sequence (Continued)
LSB of Count - Counter 1
LSB of Count - Counter 0
MSB of Count - Counter 0
MSB of Count - Counter 1
MSB of Count - Counter 2
A1
0
0
0
0
1
A0
1
0
0
1
0
Possible Programming Sequence
Control Word - Counter 2
Control Word - Counter 1
Control Word - Counter 0
LSB of Count - Counter 2
MSB of Count - Counter 2
LSB of Count - Counter 1
MSB of Count - Counter 1
LSB of Count - Counter 0
MSB of Count - Counter 0
A1 A0
11
11
11
10
10
01
01
00
00
Possible Programming Sequence
A1 A0
Control Word - Counter 1
11
Control Word - Counter 0
11
LSB of Count - Counter 1
01
Control Word - Counter 2
11
LSB of Count - Counter 0
00
MSB of Count - Counter 1
01
LSB of Count - Counter 2
10
MSB of Count - Counter 0
00
MSB of Count - Counter 2
10
NOTE: In all four examples, all counters are programmed to
Read/Write two-byte counts. These are only four of many
programming sequences.
A new initial count may be written to a Counter at any time
without affecting the Counter’s programmed Mode in any way.
Counting will be affected as described in the Mode definitions.
The new count must follow the programmed count format.
If a Counter is programmed to read/write two-byte counts,
the following precaution applies. A program must not transfer
control between writing the first and second byte to another
routine which also writes into that same Counter. Otherwise,
the Counter will be loaded with an incorrect count.
Read Operations
It is often desirable to read the value of a Counter without
disturbing the count in progress. This is easily done in the
82C54.
There are three possible methods for reading the Counters.
The first is through the Read-Back command, which is
explained later. The second is a simple read operation of the
Counter, which is selected with the A1, A0 inputs. The only
requirement is that the CLK input of the selected Counter
must be inhibited by using either the GATE input or external
logic. Otherwise, the count may be in process of changing
when it is read, giving an undefined result.
Counter Latch Command
The other method for reading the Counters involves a spe-
cial software command called the “Counter Latch Com-
mand”. Like a Control Word, this command is written to the
Control Word Register, which is selected when A1, A0 = 11.
Also, like a Control Word, the SC0, SC1 bits select one of
the three Counters, but two other bits, D5 and D4, distin-
guish this command from a Control Word.
.
A1, A0 = 11; CS = 0; RD = 1; WR = 0
D7 D6 D5 D4 D3 D2 D1 D0
SC1 SC0 0 0 X X X X
SC1, SC0 - specify counter to be latched
SC1 SC0
COUNTER
00
0
01
1
10
2
11
Read-Back Command
D5, D4 - 00 designates Counter Latch Command, X - Don’t Care.
NOTE: Don’t Care bits (X) should be 0 to insure compatibility with
future products.
The selected Counter’s output latch (OL) latches the count
when the Counter Latch Command is received. This count is
held in the latch until it is read by the CPU (or until the Counter
is reprogrammed). The count is then unlatched automatically
and the OL returns to “following” the counting element (CE).
This allows reading the contents of the Counters “on the fly”
without affecting counting in progress. Multiple Counter Latch
Commands may be used to latch more than one Counter.
Each latched Counter’s OL holds its count until read. Counter
Latch Commands do not affect the programmed Mode of the
Counter in any way.
If a Counter is latched and then, some time later, latched
again before the count is read, the second Counter Latch
Command is ignored. The count read will be the count at the
time the first Counter Latch Command was issued.
With either method, the count must be read according to the
programmed format; specifically, if the Counter is pro-
grammed for two byte counts, two bytes must be read. The
two bytes do not have to be read one right after the other;
read or write or programming operations of other Counters
may be inserted between them.
Another feature of the 82C54 is that reads and writes of the
same Counter may be interleaved; for example, if the
Counter is programmed for two byte counts, the following
sequence is valid.
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CD82C54 pdf, datenblatt
82C54
Counter
New counts are loaded and Counters are decremented on
the falling edge of CLK.
The largest possible initial count is 0; this is equivalent to 216
for binary counting and 104 for BCD counting.
The counter does not stop when it reaches zero. In Modes 0,
1, 4, and 5 the Counter “wraps around” to the highest count,
either FFFF hex for binary counting or 9999 for BCD count-
ing, and continues counting. Modes 2 and 3 are periodic; the
Counter reloads itself with the initial count and continues
counting from there.
SIGNAL
STATUS
MODES
LOW OR
GOING LOW
RISING
HIGH
0 Disables Counting - Enables Counting
1 - 1) Initiates
-
Counting
2) Resets output
after next clock
2 1) Disables
Initiates Counting Enables Counting
counting
2) Sets output im-
mediately high
3 1) Disables
Initiates Counting Enables Counting
counting
2) Sets output im-
mediately high
4 1) Disables
Counting
- Enables Counting
5 - Initiates Counting -
MODE
MIN COUNT
MAX COUNT
010
110
220
320
410
510
NOTE: 0 is equivalent to 216 for binary counting and 104 for BCD
counting.
FIGURE 16. MINIMUM AND MAXIMUM INITIAL COUNTS
FIGURE 15. GATE PIN OPERATIONS SUMMARY
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