XR16L788_05 Datasheet, PDF (53/54 Pages) Exar Corporation – HIGH PERFORMANCE 2.97V TO 5.5V OCTAL UART

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REV. 1.2.2
XR16L788
HIGH PERFORMANCE 2.97V TO 5.5V OCTAL UART
GENERAL DESCRIPTION ............................................................................................... 1
APPLICATIONS ........................................................................................................................................... 1
FEATURES ................................................................................................................................................ 1
Figure 1. Block Diagram ......................................................................................................................... 1
Figure 2. Pin Out of the Device .............................................................................................................. 2
ORDERING INFORMATION ........................................................................................................................... 2
PIN DESCRIPTIONS ....................................................................................................... 3
1.0 DESCRIPTION ........................................................................................................................................ 7
2.0 Functional Descriptions ........................................................................................................................ 7
2.1 DEVICE RESET ...................................................................................................................................................... 7
2.2 UART CHANNEL SELECTION .................................................................................................................................. 7
TABLE 1: UART CHANNEL SELECTION ...................................................................................................... 7
2.3 SIMULTANEOUS WRITE TO ALL CHANNELS .............................................................................................................. 7
2.4 INT# OUPUT ......................................................................................................................................................... 8
TABLE 2: INT# PIN OPERATION FOR TRANSMITTER ................................................................................... 8
TABLE 3: INT# PIN OPERATION FOR RECEIVER ........................................................................................ 8
2.5 CRYSTAL OSCILLATOR / BUFFER ................................................................................................................... 8
Figure 3. Typical oscillator connections ................................................................................................. 8
2.6 PROGRAMMABLE BAUD RATE GENERATOR ............................................................................................................. 9
Figure 4. External Clock Connection for Extended Data Rate ............................................................... 9
Figure 5. Baud Rate Generator .............................................................................................................. 9
TABLE 4: TYPICAL DATA RATES WITH A 14.7456 MHZ CRYSTAL OR EXTERNAL CLOCK AT 16X SAMPLING .. 10
2.7 TRANSMITTER ...................................................................................................................................................... 10
Figure 6. Transmitter Operation in non-FIFO Mode ............................................................................. 11
Figure 7. Transmitter Operation in FIFO and Flow Control Mode ........................................................ 11
2.8 RECEIVER ........................................................................................................................................................... 11
Figure 8. Receiver Operation in non-FIFO Mode ................................................................................. 12
Figure 9. Receiver Operation in FIFO and Auto RTS Flow Control Mode ........................................... 12
2.9 THR AND RHR REGISTER LOCATIONS ................................................................................................................. 13
TABLE 5: TRANSMIT AND RECEIVE HOLDING REGISTER LOCATIONS, 16C550 COMPATIBLE ....................... 13
2.10 AUTOMATIC RTS/DTR HARDWARE FLOW CONTROL OPERATION ........................................................................ 13
Figure 10. Auto RTS/DTR and CTS/DSR Flow Control Operation ...................................................... 15
2.11 AUTO XON/XOFF (SOFTWARE) FLOW CONTROL .................................................................................................. 16
TABLE 6: AUTO XON/XOFF (SOFTWARE) FLOW CONTROL ........................................................................ 16
2.12 SPECIAL CHARACTER DETECT .......................................................................................................................... 16
2.13 AUTO RS485 HALF-DUPLEX CONTROL .............................................................................................................. 16
2.14 INFRARED MODE ............................................................................................................................................... 17
Figure 11. Infrared Transmit Data Encoding and Receive Data Decoding .......................................... 17
2.15 SLEEP MODE WITH AUTO WAKE-UP .................................................................................................................. 18
2.16 INTERNAL LOOPBACK ......................................................................................................................................... 19
Figure 12. Internal Loop Back .............................................................................................................. 19
3.0 XR16L788 REGISTERS ....................................................................................................................... 20
Figure 13. The XR16L788 Registers .................................................................................................... 20
3.1 DEVICE CONFIGURATION REGISTER SET ................................................................................. 20
TABLE 7: XR16L788 REGISTER SETS .................................................................................................... 20
TABLE 8: DEVICE CONFIGURATION REGISTERS ........................................................................................ 21
Figure 14. The Global Interrupt Registers, INT0, INT1, INT2 and INT3 ............................................... 22
TABLE 9: UART CHANNEL [7:0] INTERRUPT SOURCE ENCODING AND CLEARING ...................................... 23
Figure 15. Timer/Counter circuit ........................................................................................................... 23
TABLE 10: TIMER CONTROL REGISTER ............................................................................................... 24
3.2 UART CHANNEL CONFIGURATION REGISTERS .......................................................................................... 27
TABLE 11: UART CHANNEL CONFIGURATION REGISTERS ............................................................ 27
TABLE 12: UART CHANNEL CONFIGURATION REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED
BY EFR BIT-4. ........................................................................................................................................ 28
4.0 Internal Register Descriptions ........................................................................................................... 29
4.1 RECEIVE HOLDING REGISTER (RHR) - READ ONLY .............................................................................................. 29
4.2 TRANSMIT HOLDING REGISTER (THR) - WRITE ONLY ........................................................................................... 29
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