ST16C452 ST16C452PS DUAL UART WITH PARALLEL PRINTER PORT March 2004 DESCRIPTION The ST16C452/ST16C452PS (452/452PS) is a dual universal asynchronous receiver and transmitter (UART) with an added bi-directional parallel port that is directly compatible with a CENTRONICS type printer. The parallel port is designed such that the user can configure it as general purpose I/O interface, or for connection to other printer devices. The 452/452PS provides enhanced UART functions, a modem control interface, and data rates up to 1.5Mbps. Onboard status registers provide the user with error indications and operational status. The system interrupts and control may be tailored to meet user requirements. An internal loop-back capability allows onboard diagnostics. A programmable baud rate generator is provided to select transmit and receive clock rates from 50 bps to 1.5 Mbps. The 452/452PS is available in a 68 pin PLCC package. The 452/452PS is compatible with the 16C450. The 452 is available in two versions, the ST16C452 and the ST16C452PS. The ST16C452 provides single hardware pin to control the printer port data direction while the 452PS provides an additionally software control bit to control the printer port data direction to become compatible PS/2 operating system. The 452/452PS is fabricated in an advanced CMOS process with low power consumption. PLCC Package FEATURES Added features in devices with top mark date code ofF2 YYW and newer: TXB 10 60 INTB 5V Tolerant Inputs -DTRB 11 59 INTP -RTSB 12 58 -SLCTIN Pin to pin and functional compatible to TL16C452 -CTSB 13 57 INIT 2.97 to 5.5 volt operation D0 14 56 -AUTOFDXT Software compatible with ST16C450, NS16C450 D1 15 55 -STROBE D2 16 54 GND 1.5 Mbps transmit/receive operation (24MHz) D3 17 53 PD0 Independent transmit and receive control ST16C452CJ68 18 52 PD1 D4 ST16C452CJ68PS Modem and printer status registers D5 19 51 PD2 UART port and printer port Bi-directional D6 20 50 PD3 D7 21 49 PD4 Printer port direction set by single control bit or 8 bit N.C. 22 48 PD5 pattern (AA/55) VCC 23 47 PD6 Modem control signals (-CTS, -RTS, -DSR, -DTR, -RTSA 24 46 PD7 -RI, -CD) -DTRA 25 45 INTA TXA 26 44 RDOUT Programmable character lengths (5, 6, 7, 8) Even, odd, or no parity bit generation and detection Internal loop-back diagnostics TTL compatible inputs, outputs Low Power ORDERING INFORMATION Part number Package Operating temperature Device Status ST16C452CJ68 68-Lead PLCC 0 C to + 70 C Active ST16C452CJ68PS 68-Lead PLCC 0 C to + 70 C Active ST16C452IJ68 68-Lead PLCC -40 C to + 85 C Active ST16C452IJ68PS 68-Lead PLCC -40 C to + 85 C Active Rev. 3.20 EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 (510) 668-7000 FAX (510) 668-7017 GND 9 27 N.C. -CTSA 28 8 -CDB -CDA 29 7 GND -RIA 30 6 -RIB -DSRA 31 5 -DSRB -CSA 32 4 CLK A2 33 3 -CSB A1 34 2 GND A0 35 1 BIDEN -IOW 36 68 ACK -IOR 37 67 PE -CSP 38 66 -BUSY -RESET 39 65 SLCT VCC 40 64 VCC RXA 41 63 ERROR N.C. 42 62 RXB INTSEL 43 61 N.C.ST16C452/452PS Figure 1, Block Diagram Transmit Transmit Holding Shift TX A,B D0-D7 Registers Register -IOR -IOW -RESET Receive Receive BIDEN Holding Shift RX A,B Registers Register Printer PD0-PD7 Data Ports -STROBE INIT A0-A2 -AUTOFDX -CSA Printer -SELCTIN -CSB Control -CSP Logic PE, SELECT -BUSY, -ACK ERROR -DTR A,B -RTS A,B Modem -CTS A,B Control Clock -RI A,B Logic INT A,B & -CD A,B INTP Baud Rate -DSR A,B Generator Rev. 3.20 2 Interrupt Register Data bus Control Select & Logic Logic Control Logic Inter Connect Bus Lines & Control signals CLK