xr XR16C850 2.97V TO 5.5V UART WITH 128-BYTE FIFO AUGUST 2005 REV. 2.3.1 FEATURES GENERAL DESCRIPTION Added feature in devices with top mark date code of 1 The XR16C850 (850) is a Universal Asynchronous F2 YYW and newer: Receiver and Transmitter (UART). This device 5 volt tolerant inputs supports Intel and PC mode data bus interface and is 0 ns address hold time (T ) software compatible to industry standard 16C450, AH 16C550, ST16C580 and ST16C650A UARTs. 2.97 to 5.5 volt operation The 850 has 128 bytes of TX and RX FIFOs and is Pin to pin compatible to ST16C550, ST16C580, capable of operating up to a serial data rate of 2 ST16C650A and TL16C750 Mbps. The internal registers include the 16C550 128-byte Transmit and Receive FIFOs register set plus Exars enhanced registers for additional features to support todays highly Transmit/Receive FIFO Counters demanding data communication needs. The Programmable TX/RX FIFO Trigger Levels enhanced features include automatic hardware and Automatic Hardware/Software Flow Control software flow control, selectable TX and RX trigger levels, and wireless infrared (IrDA) encoder/decoder. Auto RS-485 half duplex direction support The XR16C850 is available in the 44 pin PLCC and Programmable Xon/Xoff characters 48 pin TQFP packages. They both provide the Infrared (IrDA) TX and RX Encoder/Decoder standard Intel Bus mode and PC ISA bus (PC) mode. Sleep Mode (100 uA stand-by) The Intel Bus mode is compatible with the ST16C450 and ST16C550 while the PC mode allows connection APPLICATIONS to the PC ISA bus. Battery Operated Electronics NOTE: 1 Covered by U.S. patent 5,649,122 and 5,949,787. Internet Appliances Handheld Terminal Personal Digital Assistants Cellular Phones DataPort Wireless Infrared Data Communications Systems FIGURE 1. BLOCK DIAGRAM RESET 128 Byte TX FIFO A2:A0 Transmitter TX D7:D0 Infrared IOR Encoder IOR IOW CTS Flow UART Control Configuration IOW Intel or DTR , RTS Regs PC Data CS2 M odem Control Signals Bus DSR , CTS , CS1 Interface CD , RI RTS Flow CS0 Control Infrared INT Decoder TXRDY RXRDY RX Receiver DDIS 128 Byte RX FIFO BRG Prescaler PCMODE Baud Rate Generator S1 PC S2 Mode: COM 1 to S3 XTAL1/CLK 4 Crystal Osc/Buffer IRQA Decode Logic XTAL2 IRQB IRQC Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com XR16C850 xr 2.97V TO 5.5V UART WITH 128-BYTE FIFO REV. 2.3.1 FIGURE 2. PINOUTS IN INTEL BUS MODE AND PC MODE, TQFP AND PLCC PACKAGES 48-TQFP PACKAGE N.C. 1 36 SEL D5 2 35 RESET D6 3 34 OP1 /RS485 44-PLCC PACKAGE D7 4 33 DTR RCLK 5 32 RTS XR16C850CM N.C. 6 31 OP2 Intel Bus Mode (SEL = VCC) RX 7 30 INT 8-Bit Bus Mode TX 8 29 RXRDY CS0 9 28 A0 D5 7 39 RESET CS1 10 27 A1 D6 8 38 OP1 /RS485 -CS2 11 26 A2 D7 9 37 DTR -BAUDOUT 12 25 BUS 8/16 RCLK 10 36 RTS RX 11 35 OP2 XR16C850CJ N.C. 12 34 SEL Intel Bus Mode (SEL = VCC) TX 13 33 INT 8-Bit Bus Mode Only CS0 14 32 RXRDY CS1 15 31 A0 CS2 16 30 A1 BAUDOUT 17 29 A2 D11 1 36 SEL D5 2 35 RESET D6 3 34 OP1 /RS485 DTR D7 4 33 RCLK 5 32 RTS XR16C850CM N.C. 6 31 OP2 Intel Bus Mode (SEL = VCC) RX 7 30 INT 16-Bit Bus Mode TX 8 29 RXRDY D5 7 39 RESET A0 CS0 9 28 CS1 10 27 A1 D6 8 38 OP1 /RS485 -CS2 11 26 A2 D7 9 37 DTR -BAUDOUT 12 25 BUS 8/16 S2 10 36 RTS RX 11 35 S3 XR16C850CJ A4 12 34 SEL PC Mode (SEL = GND) TX 13 33 IRQA 8-Bit Bus Mode Only A5 14 32 IRQB 15 31 A6 A0 16 30 A7 A1 LPT1 17 29 A2 N.C. 1 36 SEL RESET D5 2 35 OP1 /RS485 D6 3 34 4 33 DTR D7 S2 5 32 RTS XR16C850CM A4 6 31 S3 PC Mode (SEL = GND) RX 7 30 IRQA 8-Bit Bus Mode Only TX 8 29 IRQB A5 9 28 A0 A6 10 27 A1 A2 A7 11 26 BUS 8/16 LPT1 12 25 2 CLKSEL 13 48 N.C. CLKSEL 13 48 N.C. CLKSEL 13 48 D10 XTAL1 14 47 D4 XTAL1 14 47 D4 47 XTAL1 14 D4 XTAL2 15 46 D3 XTAL2 15 46 D3 XTAL2 15 46 D3 45 IOW 16 45 D2 IOW 16 D2 IOW 16 45 D2 A8 17 44 D1 IOW 17 44 D1 IOW 17 44 D1 GND 18 43 D0 43 GND 18 43 D0 GND 18 D0 42 IOR 19 42 VCC IOR 42 VCC IOR 19 VCC 19 41 A3 20 41 RI IOR 20 41 RI IOR 20 RI 40 CD S1 21 40 CD 21 40 CD N.C. 21 N.C. 39 22 39 DSR LPT2 22 DSR D12 22 39 DSR DDIS IRQC 38 CTS TXRDY 38 TXRDY 23 38 CTS 23 23 CTS AEN 24 37 A9 AS 24 37 N.C. AS 24 37 N.C. XTAL1 18 6 D4 XTAL1 18 6 D4 XTAL2 19 5 D3 XTAL2 19 5 D3 IOW 20 4 D2 IOW 20 4 D2 IOW 21 3 D1 A8 21 3 D1 GND 22 2 D0 GND 22 2 D0 N.C. 23 1 N.C. S1 23 1 A9 IOR 24 44 VCC IOR 24 44 VCC IOR 25 43 RI A3 25 43 RI DDIS 26 42 CD 26 42 CD LPT2 TXRDY 27 41 DSR 27 41 DSR IRQC 28 AS 40 CTS 28 40 AEN CTS