ST16C2450 View Datasheet(PDF) - Exar Corporation

Part Name

Description

MFG CO.

ST16C2450

2.97V TO 5.5V DUART

Exar Corporation 

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REV. 4.0.1

TABLE OF CONTENTS

ST16C2450

2.97V TO 5.5V DUART

GENERAL DESCRIPTION................................................................................................. 1

APPLICATIONS ............................................................................................................................................... 1

FEATURES ..................................................................................................................................................... 1

FIGURE 1. ST16C2450 BLOCK DIAGRAM ......................................................................................................................................... 1

FIGURE 2. PIN OUT ASSIGNMENT ..................................................................................................................................................... 2

ORDERING INFORMATION ................................................................................................................................ 2

PIN DESCRIPTIONS ......................................................................................................... 3

1.0 PRODUCT DESCRIPTION .................................................................................................................... 5

2.0 FUNCTIONAL DESCRIPTIONS ............................................................................................................ 5

2.1 CPU INTERFACE ............................................................................................................................................. 5

FIGURE 3. ST16C2450 DATA BUS INTERCONNECTIONS.................................................................................................................. 6

2.2 DEVICE RESET ................................................................................................................................................ 6

2.3 CHANNEL A AND B SELECTION ................................................................................................................... 6

TABLE 1: CHANNEL A AND B SELECT ............................................................................................................................................... 6

2.4 CHANNEL A AND B INTERNAL REGISTERS ................................................................................................ 6

2.5 INTA AND INTB OUTPUTS .............................................................................................................................. 7

TABLE 2: INTA AND INTB PINS OPERATION FOR TRANSMITTER ........................................................................................................ 7

2.6 CRYSTAL OSCILLATOR OR EXTERNAL CLOCK INPUT ............................................................................. 7

FIGURE 4. TYPICAL OSCILLATOR CONNECTIONS................................................................................................................................. 7

2.7 PROGRAMMABLE BAUD RATE GENERATOR ............................................................................................. 8

TABLE 3: TYPICAL DATA RATES WITH A 14.7456 MHZ CRYSTAL OR EXTERNAL CLOCK ........................................................................ 8

2.8 TRANSMITTER ................................................................................................................................................. 8

2.8.1 TRANSMIT HOLDING REGISTER (THR) - WRITE ONLY........................................................................................... 8

FIGURE 5. TRANSMITTER OPERATION ............................................................................................................................................... 9

2.9 RECEIVER ........................................................................................................................................................ 9

2.9.1 RECEIVE HOLDING REGISTER (RHR) - READ-ONLY .............................................................................................. 9

FIGURE 6. RECEIVER OPERATION..................................................................................................................................................... 9

2.10 INTERNAL LOOPBACK ............................................................................................................................... 10

FIGURE 7. INTERNAL LOOP BACK IN CHANNELS A AND B ................................................................................................................ 10

3.0 UART INTERNAL REGISTERS ........................................................................................................... 11

TABLE 4: UART CHANNEL A AND B UART INTERNAL REGISTERS ..................................................................................... 11

TABLE 5: INTERNAL REGISTERS DESCRIPTION ................................................................................................................... 12

4.0 INTERNAL REGISTER DESCRIPTIONS ............................................................................................ 12

4.1 RECEIVE HOLDING REGISTER (RHR) - READ- ONLY ............................................................................... 12

4.2 TRANSMIT HOLDING REGISTER (THR) - WRITE-ONLY ............................................................................ 12

4.3 INTERRUPT ENABLE REGISTER (IER) - READ/WRITE ............................................................................. 12

4.3.1 INTERRUPT MODE OPERATION .............................................................................................................................. 13

4.3.2 POLLED MODE OPERATION .................................................................................................................................... 13

4.4 INTERRUPT STATUS REGISTER (ISR) - READ-ONLY ............................................................................... 13

4.4.1 INTERRUPT GENERATION: ...................................................................................................................................... 14

4.4.2 INTERRUPT CLEARING: ........................................................................................................................................... 14

TABLE 6: INTERRUPT SOURCE AND PRIORITY LEVEL ....................................................................................................................... 14

4.5 LINE CONTROL REGISTER (LCR) - READ/WRITE ..................................................................................... 14

TABLE 7: PARITY SELECTION .......................................................................................................................................................... 15

4.6 MODEM CONTROL REGISTER (MCR) OR GENERAL PURPOSE OUTPUTS CONTROL - READ/WRITE 16

4.7 LINE STATUS REGISTER (LSR) - READ ONLY ........................................................................................... 16

4.8 MODEM STATUS REGISTER (MSR) - READ ONLY .................................................................................... 17

4.9 SCRATCH PAD REGISTER (SPR) - READ/WRITE ...................................................................................... 18

4.10 BAUD RATE GENERATOR REGISTERS (DLL AND DLM) - READ/WRITE .............................................. 18

TABLE 8: UART RESET CONDITIONS FOR CHANNEL A AND B.............................................................................................. 19

ABSOLUTE MAXIMUM RATINGS .................................................................................. 20

TYPICAL PACKAGE THERMAL RESISTANCE DATA (MARGIN OF ERROR: ± 15%) 20

ELECTRICAL CHARACTERISTICS................................................................................ 20

DC ELECTRICAL CHARACTERISTICS.............................................................................................................. 20

AC ELECTRICAL CHARACTERISTICS.............................................................................................................. 21

Unless otherwise noted: 0o to 70oC (-40o to +85oC for industrial grade package), Vcc is 2.97V to 5.5V, 70 pF load

where applicable ....................................................................................................................................................... 21

FIGURE 8. CLOCK TIMING............................................................................................................................................................... 22

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