BASIC stamp manual v2.2
5: BASIC Stamp Command Reference – SERIN
BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com • Page 411
b. Add more and more small pieces, testing them each time,
as you go.
c. Never write a large portion of code that works with serial
communication without testing its smallest workable
pieces first.
2. Pay attention to timing.
a. Be very careful to calculate and overestimate the amount
of time operations should take within the BASIC Stamp.
Misunderstanding the timing constraints is the source of
most problems with code that communicate serially.
b. If the serial communication in your project is bi-
directional, the above statement is even more critical.
3. Pay attention to wiring.
a. Take extra time to study and verify serial communication
wiring diagrams. A mistake in wiring can cause strange
problems in communication, or no communication at all.
Make sure to connect the ground pins (Vss) between the
devices that are communicating serially.
4. Verify port setting on the PC and in the SERIN/SEROUT
commands.
a. Unmatched settings on the sender and receiver side will
cause garbled data transfers or no data transfers. If the
data you receive is unreadable, it is most likely a baud
rate setting error.
5. If receiving data from another device that is not a BASIC Stamp,
try to use baud rates of 4800 and below.
a. Because of additional overhead in the BASIC Stamp, and
the fact that the BASIC Stamp has no hardware receive
buffer for serial communication, received data may
sometimes be missed or garbled. If this occurs, try
lowering the baud rate (if possible), adding extra stop bits,
and not using formatters in the SERIN command. Using
simple variables (not arrays) and no formatters will
increase the chance that the BASIC Stamp can receive the
data properly.
6. Be sure to study the effects of SERIN formatters.
a. Some formatters have specific requirements that may
cause problems in received data. For example, the DEC
formatter requires a non-decimal-numeric character to
follow the received number before it will allow the BASIC