EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 • (510) 668-7000 • FAX (510) 668-7017
ST16C454
ST68C454
Rev. 3.20
QUAD UNIVERSAL ASYNCHRONOUS
RECEIVER/TRANSMITTER (UART)
DESCRIPTION
The ST16C454 is a universal asynchronous receiver
and transmitter (UART) with a dual foot print interface.
The 454 is an enhanced UART with data rates up to
1.5Mbps and software compatible to ST16C450.
Onboard status registers provide the user with error
indications and operational status, modem interface
control. System interrupts may be tailored to meet
user requirements. An internal loop-back capability
allows onboard diagnostics. The ST16C454 offer an
additional 68 mode which allows easy integration with
Motorola, and other popular microprocessors. The
454 combines the package interface modes of the
ST16C454 and ST68C454 series on a single inte-
grated chip.
FEATURES
• Software compatibility with the Industry Standard
16C450
• 1.5 Mbps transmit/receive operation (24MHz)
• Independent transmit and receive control
• Software selectable Baud Rate Generator
• Modem control signals (-CTS, -RTS, -DSR, -DTR,
-RI, -CD)
• 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 Pins Package Operating temperature
ST16C454CJ68 68 PLCC 0° C to + 70° C
ST16C454IJ68 68 PLCC -40° C to + 85° C
9
8
7
6
5
4
3
2
1
68
67
66
65
64
63
62
61
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
-DSRA
-CTSA
-DTRA
VCC
-RTSA
INTA
-CSA
TXA
-IOW
TXB
-CSB
INTB
-RTSB
GND
-DTRB
-CTSB
-DSRB
-CDB
-RIB
RXB
VCC
16/-68
A2
A1
A0
XTAL1
XTAL2
RESET
N.C.
N.C.
GND
RXC
-RIC
-CDC
-DSRD
-CTSD
-DTRD
GND
-RTSD
INTD
-CSD
TXD
-IOR
TXC
-CSC
INTC
-RTSC
VCC
-DTRC
-CTSC
-DSRC
-CDA
-RIA
RXA
GND
D7
D6
D5
D4
D3
D2
D1
D0
INTSEL
VCC
RXD
-RID
-CDD
ST16C454CJ68
16 MODE
PLCC Package
9
8
7
6
5
4
3
2
1
68
67
66
65
64
63
62
61
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
-DSRA
-CTSA
-DTRA
VCC
-RTSA
-IRQ
-CS
TXA
R/-W
TXB
A3
N.C.
-RTSB
GND
-DTRB
-CTSB
-DSRB
-CDB
-RIB
RXB
VCC
16/-68
A2
A1
A0
XTAL1
XTAL2
-RESET
N.C.
N.C.
GND
RXC
-RIC
-CDC
-DSRD
-CTSD
-DTRD
GND
-RTSD
N.C.
N.C.
TXD
N.C.
TXC
A4
N.C.
-RTSC
VCC
-DTRC
-CTSC
-DSRC
-CD
-RIA
RXA
GND
D7
D6
D5
D4
D3
D2
D1
D0
N.C.
VCC
RXD
-RID
-CD
ST16C454CJ68
68 MODE
