BASIC stamp manual v2.2

Introduction to the BASIC Stamp
Page 20 • BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com
Pin Name Description
1 SOUT
Serial Out: connects to PC serial port RX pin (DB9 pin 2 / DB25
pin 3) for programming.
2 SIN
Serial In: connects to PC serial port TX pin (DB9 pin 3 / DB25 pin
2) for programming.
3 ATN
Attention: connects to PC serial port DTR pin (DB9 pin 4 / DB25
pin 20) for programming.
4 VSS
System ground: (same as pin 23 on BS2p24, or pin 39 on
BS2p40) connects to PC serial port GND pin (DB9 pin 5 / DB25
pin 7) for programming.
5-20 P0-P15
General-purpose I/O pins: each can source and sink 30 mA.
However, the total of all pins (including X0-X15, if using the
BS2p40) should not exceed 75 mA (source or sink) if using the
internal 5-volt regulator. The total per 8-pin groups (P0 – P7, P8
– 15, X0 – X7 or X8 – X15) should not exceed 100 mA (source o
r
sink) if using an external 5-volt regulator.
{21-36} X0-X15
(BS2p40 Only!) Auxiliary Bank of General-purpose I/O pins: each
can source and sink 30 mA. However, the total of all pins
(including P0 – P15) should not exceed 75 mA (source or sink) if
using the internal 5-volt regulator. The total per 8-pin groups (P0
– P7, P8 – 15, X0 – X7 or X8 – X15) should not exceed 100 mA
(source or sink) if using an external 5-volt regulator.
21 {37} VDD
5-volt DC input/output: if an unregulated voltage is applied to the
VIN pin, then this pin will output 5 volts. If no voltage is applied to
the VIN pin, then a regulated voltage between 4.5V and 5.5V
should be applied to this pin.
22 {38} RES
Reset input/output: goes low when power supply is less than
approximately 4.2 volts, causing the BASIC Stamp to reset. Can
be driven low to force a reset. This pin is internally pulled high
and may be left disconnected if not needed. Do not drive high.
23 {39} VSS
System ground: (same as pin 4) connects to power supply’s
ground (GND) terminal.
24 {40} VIN
Unregulated power in: accepts 5.5 - 12 VDC (7.5 recommended),
which is then internally regulated to 5 volts. Must be left
unconnected if 5 volts is applied to the VDD (+5V) pin.
Table 1.5: BASIC Stamp 2p Pin
Connections
See the "BASIC Stamp Programming Connections" section on page 27 for
more information on the required programming connections between the
PC and the BASIC Stamp.