SP303 Datasheet, PDF (4/8 Pages) Sipex Corporation – RS232/AppleTalk TM Serial Transceiver

Pin 26 — R_OUTA1 — RXD; TTL output to
UART.
Pin 27 — N.C. — No Connection.
Pin 28 — V_CC — +5V Power Supply.
PIN ASSIGNMENTS — MACINTOSH™
APPLETALK™ MODE
Pin 1 — V_DD — +12V Power Supply.
Pin 2 — R_INA2 — Receive data; received at
UART’s RxD (non–inverted); V_IH = 0.2V;
V_IL = –0.2V; R_IN =3kΩ minimum.
Pin 3 — R_INA1 — Receive data; received at
UART’s RxD (inverted); V_IH = 0.2V;
V_IL = –0.2V; R_IN =3kΩ minimum.
Pin 4 — N.C. — No Connection.
Pin 5 — T_OUTA2 — Transmit data; driven from
UART’s TxD (non–inverted); tri–stated when
UART’s RTS is not asserted; V_OH = 3.6V min;
V_OL = –3.6V min; R_L = 450Ω.
Pin 6 — T_OUTA1 — Transmit data; driven from
UART’s TxD (inverted); tri–stated when RTS
is not asserted; V_OH = 3.6V min; V_OL = –3.6V
min R_L = 450Ω.
Pin 7 — SEL A — Select A; used with Select B
(pin 8) to select operating mode. Logic “0” on
both SEL A and SEL B selects RS-232 mode;
logic “1” on both SEL A and SEL B selects
AppleTalk™ mode.
Pin 8 — SEL B — Select B; used with Select A
(pin 7) to select operating mode. Logic “0” on
both SEL A and SEL B selects RS-232 mode;
logic “1” on both SEL A and SEL B selects
AppleTalk™ mode.
Pin 9— T_OUTB1— Handshake output; driven
Vfro_O^m_L =U–A3R.6TV’smDiTn;RR(i_L^n=ve4r5te0dΩ^{) ;.VOH = 3.6V min;}
Pin 10 — T_OUTB2 — Handshake output; driven
from UART’s DTR (non–inverted); V_OH = 3.6V
min; V_OL = –3.6V min; R_L = 450Ω.
Pin 11 — N.C. — No Connection.
Pin 12— R_INB1— Handshake input or external
clock; received non–inverted at UART’s CTS
and TRxC; V_IH = 0.2V; V_IL = –0.2V; R_IN =3kΩ
minimum.
Pin 13 — N.C. — No Connection.
Pin 14 — GND — Signal ground. Connected to
logic and chasis ground.
Pin 15 — V_EE — –12V Power Supply.
Pin 16 — N.C. — No Connection.
Pin 17 — R_OUTB1 — Receive handshake out-
put; connects to UART’s CTS and TRxC.
Pin 18 — N.C. — No Connection.
Pin 19 — T_OUTB2 — Not used in AppleTalk™
mode.
Pin 20 — T_INB1 — Transmit handshake input;
connects to UART’s DTR output.
Pin 21 — N.C. — No Connection.
Pin 22 — TxEN — Transmit data driver enable;
connects to UART’s RTS; transmit data driver
is enabled when this pin is low.
Pin 23 — T_INA1 — Transmit data input; con-
nects to UART’s TxD output.
Pin 24 — N.C. — No Connection.
Pin 25 — N.C. — No Connection.
Pin 26 — R_OUTA1 — Receive data output:
connects to UART’s RxD input.
Pin 27 — N.C. — No Connection.
Pin 28 — V_CC — +5V Power Supply.
FEATURES…
The SP303 is a single chip device that offers
both RS-232 and AppleTalk interfaces. When
configured for RS-232 mode, the SP303 pro-
vides 4 drivers and 4 receivers. When the part is
programmed for AppleTalk mode, the SP303
supports Macintosh–type ports. The mode can
be changed at any time by bringing both the SEL
A and the SEL B pins high for Mac mode, or low
for RS-232 mode.
The RS-232 line driver circuits convert TTL–
logic level inputs into inverted RS-232 output
signals. The RS-232 receivers convert the EIA
RS-232 input signals to inverted TTL output
logic levels. The receivers have voltage hyster-
esis, which helps eliminate spurious output tran-
sitions that might result from low–amplitude
noise voltages during slower-speed signal tran-
sitions.
When the SP303 is programmed for Mac mode,
the transmit data and receive data signals are
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SIGNAL PROCESSING EXCELLENCE