ST16C1451 View Datasheet(PDF) - Exar Corporation

Part Name

Description

MFG CO.

ST16C1451

2.97V TO 5.5V UART

Exar Corporation 

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2.97V TO 5.5VUART

TABLE OF CONTENTS

ST16C1450/51

REV. 4.2.0

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

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

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

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

FIGURE 2. ST16C1450 PINOUTS ..................................................................................................................................................... 2

FIGURE 3. ST16C1451 PINOUTS ..................................................................................................................................................... 3

ORDERING INFORMATION ................................................................................................................................ 4

PIN DESCRIPTIONS ......................................................................................................... 5

DATA BUS INTERFACE ............................................................................................................................................. 5

MODEM OR SERIAL I/O INTERFACE ....................................................................................................................... 5

ANCILLARY SIGNALS ................................................................................................................................................ 6

1.0 PRODUCT DESCRIPTION .................................................................................................................... 7

2.0 FUNCTIONAL DESCRIPTIONS ............................................................................................................ 7

2.1 INTERNAL REGISTERS ................................................................................................................................... 7

2.2 CRYSTAL OSCILLATOR OR EXTERNAL CLOCK ......................................................................................... 8

2.3 PROGRAMMABLE BAUD RATE GENERATOR ............................................................................................. 8

FIGURE 4. TYPICAL OSCILLATOR CONNECTIONS................................................................................................................................. 8

2.4 TRANSMITTER ................................................................................................................................................. 9

2.4.1 TRANSMIT HOLDING REGISTER (THR) - WRITE ONLY........................................................................................... 9

2.4.2 TRANSMITTER OPERATION....................................................................................................................................... 9

TABLE 1: TYPICAL DATA RATES WITH A 14.7456 MHZ CRYSTAL OR EXTERNAL CLOCK ........................................................................ 9

2.5 RECEIVER ...................................................................................................................................................... 10

2.5.1 RECEIVE HOLDING REGISTER (RHR) - READ-ONLY ............................................................................................ 10

FIGURE 5. TRANSMITTER OPERATION ............................................................................................................................................. 10

2.6 SPECIAL (ENHANCED FEATURE) MODE ................................................................................................... 11

2.6.1 SOFT RESET .............................................................................................................................................................. 11

2.6.2 POWER DOWN MODE ............................................................................................................................................... 11

2.7 INTERNAL LOOPBACK ................................................................................................................................ 11

FIGURE 6. RECEIVER OPERATION IN NON-FIFO MODE .................................................................................................................... 11

FIGURE 7. INTERNAL LOOPBACK..................................................................................................................................................... 12

3.0 UART INTERNAL REGISTERS ........................................................................................................... 13

TABLE 2: ST16C145X UART INTERNAL REGISTERS ............................................................................................................... 13

TABLE 3: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1......................................... 14

4.0 INTERNAL REGISTER DESCRIPTIONS ............................................................................................ 15

4.1 RECEIVE HOLDING REGISTER (RHR) - READ- ONLY ............................................................................... 15

4.2 TRANSMIT HOLDING REGISTER (THR) - WRITE-ONLY ............................................................................ 15

4.3 INTERRUPT ENABLE REGISTER (IER) - READ/WRITE ............................................................................. 15

4.4 INTERRUPT STATUS REGISTER (ISR) - READ-ONLY ............................................................................... 15

4.4.1 INTERRUPT GENERATION: ...................................................................................................................................... 16

4.4.2 INTERRUPT CLEARING: ........................................................................................................................................... 16

4.5 LINE CONTROL REGISTER (LCR) - READ/WRITE ..................................................................................... 16

TABLE 4: INTERRUPT SOURCE AND PRIORITY LEVEL ....................................................................................................................... 16

4.6 MODEM CONTROL REGISTER (MCR) OR GENERAL PURPOSE OUTPUTS CONTROL - READ/WRITE 18

TABLE 5: PARITY SELECTION .......................................................................................................................................................... 18

4.7 LINE STATUS REGISTER (LSR) - READ ONLY ........................................................................................... 19

4.8 MODEM STATUS REGISTER (MSR) - READ ONLY .................................................................................... 20

4.9 SCRATCH PAD REGISTER (SPR) - READ/WRITE ...................................................................................... 21

TABLE 6: UART RESET CONDITIONS ........................................................................................................................................ 21

ABSOLUTE MAXIMUM RATINGS .................................................................................. 22

TYPICAL PACKAGE THERMAL RESISTANCE DATA (MARGIN OF ERROR: ± 15%) ................................................. 22

ELECTRICAL CHARACTERISTICS................................................................................ 22

DC ELECTRICAL CHARACTERISTICS.............................................................................................................. 22

AC ELECTRICAL CHARACTERISTICS.............................................................................................................. 23

TA=0O TO 70OC (-40O TO +85OC FOR INDUSTRIAL GRADE PACKAGE), VCC IS 2.97V TO 5.5V...................... 23

FIGURE 8. CLOCK TIMING............................................................................................................................................................... 24

FIGURE 9. MODEM INPUT/OUTPUT TIMING ...................................................................................................................................... 24

FIGURE 10. DATA BUS READ TIMING .............................................................................................................................................. 25

FIGURE 11. DATA BUS WRITE TIMING ............................................................................................................................................ 25

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