ST78C34 Datasheet, PDF (1/21 Pages) Exar Corporation – GENERAL PURPOSE PARALLEL PRINTER PORT WITH 83 BYTE FIFO

ST78C34
GENERAL PURPOSE PARALLEL
PRINTER PORT WITH 83 BYTE FIFO
DESCRIPTION
The ST78C34 is a monolithic Bidirectional Parallel
port designed to operate as a general purpose I/O port.
It contains all the necessary input/output signals to be
configured as a CENTRONICS printer port.
The ST78C34 is a general purpose input/output con-
troller with 83 byte internal FIFO. FIFO operation can
be enabled or disabled. For CENTRONICS printer
operation, all registers are mapped to IBM printer port
registers.
The ST78C34 is designed to operate as normal
printer interface without any additional settings. Con-
tents of the FIFO will be cleared after reset or setting
the INIT pin to a low state. The auto FIFO operation
starts after the first -ACK is received from the printer.
Contents of the FIFO transfer to the printer at the
printer loading speed.
N.C. 7
INTSEL 8
D7 9
D6 10
D5 11
D4 12
D3 13
D2 14
D1 15
D0 16
N.C. 17
PLCC Package
ST78C34CJ44
39 N.C.
38 PD7
37 PD6
36 PD5
35 PD4
34 PD3
33 PD2
32 PD1
31 PD0
30 GND
29 N.C.
FEATURES
· 83 bytes of printer output FIFO
· Bi-directional software parallel port
· Bi-directional I/O ports
· Register compatible to IBM XT, AT, compatible
386, 486
· Selectable interrupt polarity
· Selectable FIFO interrupts
ORDERING INFORMATION
Part number
Pin
ST78C34CJ44 44
ST78C34CP40 40
ST78C34IJ44 44
ST78C34IP40 40
Package
PLCC
PDip
PLCC
PDip
Operating temperature
0° C to + 70° C
0° C to + 70° C
-40° C to + 85° C
-40° C to + 85° C
Rev. 3.00
6-3