XR16V2752_07 Datasheet, PDF (50/51 Pages) Exar Corporation – HIGH PERFORMANCE DUART WITH 64-BYTE FIFO

XR16V2752
HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
TABLE OF CONTENTS
REV. 1.0.1
GENERAL DESCRIPTION ................................................................................................ 1
APPLICATIONS............................................................................................................................................... 1
FEATURES .................................................................................................................................................... 1
FIGURE 1. XR16V2752 BLOCK DIAGRAM ......................................................................................................................................... 1
FIGURE 2. PIN OUT ASSIGNMENT ..................................................................................................................................................... 2
ORDERING INFORMATION................................................................................................................................ 2
PIN DESCRIPTIONS ........................................................................................................ 3
1.0 PRODUCT DESCRIPTION....................................................................................................................... 6
2.0 FUNCTIONAL DESCRIPTIONS............................................................................................................... 7
2.1 CPU INTERFACE................................................................................................................................................. 7
FIGURE 3. XR16L2750 DATA BUS INTERCONNECTIONS .................................................................................................................... 7
2.2 5-VOLT TOLERANT INPUTS .............................................................................................................................. 7
2.3 DEVICE RESET ................................................................................................................................................... 7
2.4 DEVICE IDENTIFICATION AND REVISION........................................................................................................ 7
2.5 CHANNEL A AND B SELECTION....................................................................................................................... 7
TABLE 1: CHANNEL A AND B SELECT ............................................................................................................................................... 8
2.6 CHANNEL A AND B INTERNAL REGISTERS ................................................................................................... 8
2.7 DMA MODE.......................................................................................................................................................... 8
TABLE 2: TXRDY# AND RXRDY# OUTPUTS IN FIFO AND DMA MODE ............................................................................................. 8
2.8 INTA AND INTB OUTPUTS ................................................................................................................................. 9
TABLE 3: INTA AND INTB PINS OPERATION FOR TRANSMITTER ........................................................................................................ 9
TABLE 4: INTA AND INTB PIN OPERATION FOR RECEIVER ............................................................................................................... 9
2.9 CRYSTAL OSCILLATOR OR EXTERNAL CLOCK INPUT ................................................................................ 9
FIGURE 4. TYPICAL OSCILLATOR CONNECTIONS................................................................................................................................. 9
2.10 PROGRAMMABLE BAUD RATE GENERATOR WITH FRACTIONAL DIVISOR.......................................... 10
FIGURE 5. BAUD RATE GENERATOR ............................................................................................................................................... 11
TABLE 5: TYPICAL DATA RATES WITH A 24 MHZ CRYSTAL OR EXTERNAL CLOCK AT 16X SAMPLING ................................................... 11
2.11 TRANSMITTER ................................................................................................................................................ 12
2.11.1 TRANSMIT HOLDING REGISTER (THR) - WRITE ONLY ......................................................................................... 12
2.11.2 TRANSMITTER OPERATION IN NON-FIFO MODE .................................................................................................. 12
FIGURE 6. TRANSMITTER OPERATION IN NON-FIFO MODE .............................................................................................................. 12
2.11.3 TRANSMITTER OPERATION IN FIFO MODE ........................................................................................................... 12
FIGURE 7. TRANSMITTER OPERATION IN FIFO AND FLOW CONTROL MODE ..................................................................................... 13
2.12 RECEIVER ....................................................................................................................................................... 13
2.12.1 RECEIVE HOLDING REGISTER (RHR) - READ-ONLY ............................................................................................ 13
FIGURE 8. RECEIVER OPERATION IN NON-FIFO MODE .................................................................................................................... 14
FIGURE 9. RECEIVER OPERATION IN FIFO AND AUTO RTS FLOW CONTROL MODE ......................................................................... 14
2.13 AUTO RTS (HARDWARE) FLOW CONTROL ................................................................................................ 15
2.14 AUTO RTS HYSTERESIS............................................................................................................................... 15
2.15 AUTO RS485 HALF-DUPLEX CONTROL ..................................................................................................... 15
2.16 AUTO CTS FLOW CONTROL ........................................................................................................................ 15
FIGURE 10. AUTO RTS AND CTS FLOW CONTROL OPERATION....................................................................................................... 16
2.17 AUTO XON/XOFF (SOFTWARE) FLOW CONTROL...................................................................................... 17
TABLE 6: AUTO XON/XOFF (SOFTWARE) FLOW CONTROL ............................................................................................................... 17
2.18 SPECIAL CHARACTER DETECT .................................................................................................................. 17
2.19 INFRARED MODE ........................................................................................................................................... 18
FIGURE 11. INFRARED TRANSMIT DATA ENCODING AND RECEIVE DATA DECODING .......................................................................... 18
2.20 SLEEP MODE WITH AUTO WAKE-UP.......................................................................................................... 19
2.21 INTERNAL LOOPBACK ................................................................................................................................. 20
FIGURE 12. INTERNAL LOOP BACK IN CHANNEL A AND B ................................................................................................................ 20
3.0 UART INTERNAL REGISTERS ............................................................................................................. 21
TABLE 7: UART CHANNEL A AND B UART INTERNAL REGISTERS ....................................................................................... 21
TABLE 8: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1 ......................................... 22
4.0 INTERNAL REGISTER DESCRIPTIONS............................................................................................... 23
4.1 RECEIVE HOLDING REGISTER (RHR) - READ- ONLY .................................................................................. 23
4.2 TRANSMIT HOLDING REGISTER (THR) - WRITE-ONLY ............................................................................... 23
4.3 INTERRUPT ENABLE REGISTER (IER) - READ/WRITE................................................................................. 23
4.3.1 IER VERSUS RECEIVE FIFO INTERRUPT MODE OPERATION ............................................................................... 24
4.3.2 IER VERSUS RECEIVE/TRANSMIT FIFO POLLED MODE OPERATION .................................................................. 24
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