ST16C552 Exar Corporation, ST16C552 Datasheet - Page 6

• Manufacturer Part Number: ST16C552
• Description: DUAL UART WITH 16-BYTE FIFO AND PARALLEL PRINTER PORT
• Manufacturer: Exar Corporation

ST16C552/552A
SYMBOL DESCRIPTION
SLCT
-SLCTIN
-STROBE
-TXRDY A/B
VCC
-CD A/B
-CTS A/B
Rev. 3.40
Symbol
23,40,64
22,42
28,13
29,8
Pin
65
58
55
Signal Type
Pwr
I/O
I/O
O
I
I
I
reached.
Select (with internal pull-up) - General purpose input or line
printer select status. Normally this pin is connected to a
printer output (active low) that indicates the ready status of
a printer, i.e., on-line and/or on-line and ready.
Select In (open drain, with internal pull-up) - General
purpose I/O or line printer select. This pin can be read via
Bit-3 in the printer command register, or written via bit-3 in
the printer control register. As this pin is open-drain, it can
be wire-or’d with other outputs. Normally this signal is
connected with a printer to select the printer with an active
low.
Strobe (open drain, with internal pull-up) - General purpose
I/O or data strobe output. Normally this output is connected
to a printer and indicates that valid data is available at the
printer port (PD0-PD7).
Transmit Ready A/B (active low). These outputs provide the
TX FIFO/THR status for individual transmit channels (A-B).
As such, an individual channel’s -TXRDY A-B buffer ready
status is indicated by logic 0, i.e., at least one location is
empty and available in the FIFO or THR. This pin goes to
a logic 1 when there are no more empty locations in the
FIFO or THR.
2.97 to 5.5V power supply input. All inputs are 5V tolerant
except for XTAL1 and all printer port inputs for devices with
revision "F" and newer.
Carrier Detect (active low) - These inputs are associated
with individual UART channels A through B. A logic 0 on this
pin indicates that a carrier has been detected by the modem
for that channel.
Clear to Send (active low) - These inputs are associated with
individual UART channels, A through B. A logic 0 on this pin(s)
indicates the modem or data set is ready to accept transmit
data from the 552/552A for the given channel. Status can be
tested by reading MSR bit-4 for that channel(s). -CTS has no
6
Pin Description