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Numéro de référence | UPD8251 | ||
Description | PROGRAMMABLE COMMUNICATIONS INTERFACE | ||
Fabricant | NEC | ||
Logo | |||
1 Page
NEe Microcomputers, Inc.
NEe
p.PD8251
p.PD8251A
PROGRAMMABLE COMMUNICATION INTERFACES
DESCRIPTION
The}.lPD8251 and}.lPD8251A Universal Synchronous/Asynchronous Receiver/
Transmitters (USARTs) are designed for microcomputer systems data communications.
The USART is used as a peripheral and is programmed by the 8080A or other
processor to communicate in commonly used serial data transmission techniques includ·
ing IBM Bi-Sync. The USART receives serial data streams and converts them into
parallel data characters for the processor. While receiving serial data, the USART will
also accept data characters from the processor in parallel format, convert them to serial
format and transmit. The USART will signal the processor when it has completely
received or transmitted a character and requires service. Complete USART status
including data format errors and control signals such as TxE and SYNDET, is available
to the processor at any time.
FEATURES
• Asynchronous or Synchronous Operation
Asynch ronous:
Five 8-Bit Characters
Clock Rate - 1, 16 or 64 x Baud Rate
Break Character Generation
Select 1, 1-1/2, or 2 Stop Bits
False Start Bit Detector
Automatic Break Detect and Handling (}.lPD8251 A)
Synchronous:
Five 8-Bit Characters
Internal or External Character Synchronization
Automatic Sync Insertion
Single or Double Sync Characters
• Baud Rate (1X Mode) - DC to 56K Baud (}.lPD8251)
- DC to 64K Baud (}.lPD8251A)
• Full Duplex, Double Buffered Transmitter and Receiver
• Parity, Overrun and Framing Flags
• Fully Compatible with 8080A/8085/}.lPD780 (Z80TM)
• All Inputs and Outputs are TTL Compatible
• Single +5 Volt Supply, ±10%
• Separate Device Receive and Transmit TTL Clocks
• 28 Pin Plastic DIP Package
• N-Channel MOS Technology
PIN CONFIGURATION 02
RxROY
0,
00
vCC
~
Di'R
RTs
DSR
RESET
CLK
T.O
TxE
CTS"
SYNDET ("PD82511
SYNDET/BD ("PD8251A)
TxRDY
0,.00
CIO
RO
WR
CS
CLK
RESeT
TxC
TxO
RxC
RxO
RxRDY
TKRDY
Q.!lR
OTR
SYNDET
SVNDET/BO
RTS
CTS
T••
Vee
GNO
PIN NAMES
Data Bus 18 bitt)
Control or Data is to be Written or Read
And Data Command
Write Data or Control Command
Chip Enable
Clock Pulse (TTL!
R. ."
Transmitter Ctock (TTL)
Transmitter o.t.
Rewlve, Clock (TTL)
Receiver Data
Receiver Ready (has character for 8080)
Transmitter Readv (readv for char. from 80an
O.t. Set Rudy
Data Terminal Ready
Sync Oetect
Sync Detect/Break Detect
Requillt to Send Oat.
CI••r 10 Send Data
Transmitter Empty
+5 V04t Supply
Ground
II
TM: Z80 is a registered trademark of Zilog.
Rev/4
583
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Pages | Pages 18 | ||
Télécharger | [ UPD8251 ] |
No | Description détaillée | Fabricant |
UPD8251 | PROGRAMMABLE COMMUNICATIONS INTERFACE | NEC |
UPD8251A | PROGRAMMABLE COMMUNICATIONS INTERFACE | NEC |
UPD8251AF | PROGRAMMABLE COMMUNICATIONS INTERFACE | NEC |
UPD8253 | PROGRAMMABLE INTERVAL TIMER | NEC |
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