ST16C552 ST16C552A DUAL UART WITH 16-BYTE FIFO AND PARALLEL PRINTER PORT December 2003 DESCRIPTION The ST16C552/ST16C552A (552/552A) 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 552/552A provides enhanced UART functions with 16 byte FIFOs, 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 552/552A is available in a 68 pin PLCC package. The 552/552A is compatible with the 16C450 and 16C550. The difference between the ST16C552 and ST16C552A is the logic state of the printer port, INTP interrupt. The INTP interrupt is active high (logic 1) on the ST16C552 whereas INTP is active low (logic 0) on the ST16C552A part when the interrupt latch mode is selected. The 552/552A is fabricated in an advanced CMOS process with power down mode to reduce the power consumption. The 552A does not support the power down mode. PLCC Package FEATURES Added features in device revision and newer: 5V Tolerant Inputs Pin to pin and functional compatible to ST16C452/ TXB 10 60 INTB 452PS, TL16C552 -DTRB 11 59 INTP 2.97 to 5.5 volt operation -RTSB 12 58 -SLCTIN -CTSB 13 57 INIT Software compatible with INS8250, NS16C550 D0 14 56 -AUTOFDXT 1.5 Mbps transmit/receive operation (24MHz) D1 15 55 -STROBE 16 byte transmit FIFO D2 16 54 GND D3 17 53 PD0 16 byte receive FIFO with error flags ST16C552CJ68 18 52 PD1 D4 ST16C552ACJ68 Independent transmit and receive control D5 19 51 PD2 Modem and printer status registers D6 20 50 PD3 D7 21 49 PD4 UART port and printer port Bi-directional -TXRDYA 22 48 PD5 Printer port direction set by single control bit or 8 bit VCC 23 47 PD6 pattern (AA/55) 24 -RTSA 46 PD7 Modem control signals (-CTS, -RTS, -DSR, -DTR, -DTRA 25 45 INTA TXA 26 44 RDOUT -RI, -CD) Programmable character lengths (5, 6, 7, 8) Even, odd, or no parity bit generation and detection TTL compatible inputs, outputs Power down mode ORDERING INFORMATION Part number Pins Package Operating temperature Device Status ST16C552CJ68 68 PLCC 0 C to + 70 C Active ST16C552ACJ68 68 PLCC 0 C to + 70 C Active ST16C552IJ68 68 PLCC -40 C to + 85 C Active ST16C552AIJ68 68 PLCC -40 C to + 85 C Active Rev. 3.40 EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 (510) 668-7000 FAX (510) 668-7017 GND 27 9 -RXRDYA -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 ACK 68 -IOR 37 67 PE -CSP 38 66 -BUSY -RESET 39 65 SLCT VCC 40 64 VCC RXA 41 63 ERROR -TXRDYB 42 62 RXB INTSEL 43 61 -RXRDYBST16C552/552A Figure 1, Block Diagram Transmit Transmit FIFO Shift TX A,B D0-D7 Registers Register -IOR -IOW -RESET Receive Receive BIDEN FIFO 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 INT A,B -RI A,B Logic & INTP -CD A,B Baud Rate -RXRDY -DSR A,B Generator -TXRDY Rev. 3.40 2 Interrupt Register Data bus Control Select & Logic Logic Control Logic Inter Connect Bus Lines & Control signals CLK