ST16C454 QUAD UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER (UART) DESCRIPTION PLCC Package The ST16C454 is a universal asynchronous receiver and transmitter (UART) with a dual foot print interface. -DSRA 10 60 -DSRD The 454 is an enhanced UART with data rates up to -CTSA 11 59 -CTSD 1.5Mbps and software compatible to ST16C450. -DTRA 12 58 -DTRD Onboard status registers provide the user with error VCC 13 57 GND -RTSA 14 56 -RTSD indications, operational status, and modem interface INTA 15 55 INTD control. System interrupts may be tailored to meet user -CSA 16 54 -CSD requirements. An internal loop-back capability allows TXA 17 53 TXD onboard diagnostics. The ST16C454 offer an additional ST16C454CJ68 -IOW 18 52 -IOR 16 MODE 68 mode which allows easy integration with Motorola, TXB 19 51 TXC -CSB 20 50 -CSC and other popular microprocessors. The 454 combines INTB 21 49 INTC the package interface modes of the ST16C454 on a -RTSB 22 48 -RTSC single integrated chip with a selection pin. GND 23 47 VCC -DTRB 24 46 -DTRC -CTSB 25 45 -CTSC -DSRB 26 44 -DSRC FEATURES -DSRA 10 60 -DSRD Software compatibility with the Industry Standard -CTSA 11 59 -CTSD 16C450 -DTRA 12 58 -DTRD 2.97 to 5.5 volt operation VCC 13 57 GND Intel or Motorola data bus interface select -RTSA 14 56 -RTSD -IRQ 15 55 N.C. 1.5 Mbps transmit/receive operation (24MHz) -CS 16 54 N.C. Independent transmit and receive control TXA 17 53 TXD Software selectable Baud Rate Generator ST16C454CJ68 R/-W 18 52 N.C. 68 MODE Modem control signals (-CTS, -RTS, -DSR, -DTR, 19 TXB 51 TXC -RI, -CD) 20 50 A3 A4 N.C. 21 49 N.C. Programmable character lengths (5, 6, 7, 8) -RTSB 22 48 -RTSC Even, odd, or no parity bit generation and detection GND 23 47 VCC Internal loop-back diagnostics -DTRB 24 46 -DTRC TTL compatible inputs, outputs -CTSB 25 45 -CTSC Low power -DSRB 26 44 -DSRC ORDERING INFORMATION Part number Package Operating temperature Device Status ST16C454CJ68 68-Lead PLCC 0 C to + 70 C Active ST16C454IJ68 68-Lead PLCC -40 C to + 85 C Active Rev. 3.31 EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 (510) 668-7000 FAX (510) 668-7017 -CDB 27 9 -CDA -CDB 27 9 -CDA -RIB 28 8 -RIA -RIB 28 8 -RIA RXB 29 7 RXA RXB 29 7 RXA VCC 30 6 GND VCC 30 6 GND 16/-68 31 5 D7 16/-68 31 5 D7 A2 32 4 D6 A2 32 4 D6 A1 33 3 D5 A1 33 3 D5 A0 34 2 D4 A0 34 2 D4 XTAL1 35 1 D3 XTAL1 35 1 D3 XTAL2 36 68 D2 XTAL2 36 68 D2 -RESET 37 67 D1 RESET 37 67 D1 N.C. 38 66 D0 N.C. 38 66 D0 N.C. INTSEL N.C. 39 65 N.C. 39 65 VCC VCC GND 40 64 GND 40 64 RXD RXD RXC 41 63 RXC 41 63 -RIC 42 62 -RID -RIC 42 62 -RID -CDC 43 61 -CDD -CDC 43 61 -CDDST16C454 Figure 2, Block Diagram in 16 Mode Transmit Transmit TX A-D Holding Shift D0-D7 Registers Register -IOR -IOW RESET Receive Receive A0-A2 Holding Shift RX A-D -CS A-D Registers Register INT A-D INTSEL -DTR A-D -RTS A-D Modem -CTS A-D XTAL1 Control -RI A-D Logic -CD A-D -DSR A-D XTAL2 Rev. 3.31 2 Clock Interrupt Register Data bus & Control Select & Baud Rate Logic Logic Control Logic Generator Inter Connect Bus Lines & Control signals