Remote Processing RPC-210 - Manual (Page 19)

SERIAL & SPI PORTS BASIC SECTION 4
Page 4-1
Figur e 4-1 Ser ial Com municatio n Por ts
DESCRIPTION
SERIAL PORTS S E C T IO N 4
The RP C-210 h as two ser ial ports that inter face to
printers, terminals, RS-485 network, or other serial
devices. A clock an d data lines for SPI com patible
devices is also av ailable. This section d escribes their
c h ar a c te r is ti c s a n d h o w t o u s e t he m .
Serial por ts are num bered C OM 0 and CO M1. COM 0 is
RS-232 on ly and is used for progr am deve lopment.
During r un time, it can be used for other functions.
COM 1 is a general purpose port and is jumperable for
RS-232 or RS-422/485.
Each port has a 256 character interr upt driven input and
output buffer. This allows characters to be sent out
(using PRINT) without slowing down program
execution. However, if the PRINT buffer fills, program
execution is susp ended until all P RINT charac ters ar e in
the buffer. Both ports have a 256 character input buffer.
When m ore than 256 char acters are r eceived, excess
ones are ignored.
CON FIG BAU D controls baud rate and RS-232/485
mode (CO M1 only).
ON C OM $ is useful whe n data is sent in pac kets. This
multitasking command branches to a BASIC subroutine
when a sp ecific char acter or number of chara cters is
received.
COM 1 UART uses INT0 interrupt. This interrupt may
be used with the real time clock, counter/ encoder, or for
externa l interru pts at J8-6 or J7-3. COM 1 uses this
interrupt for serial comm unications. If you ne ed to use
INT0 for the re al time clock or external use, then you
can not use COM 1 for serial communication.
COM0 SERIAL PORT
This port at J1 uses a VTC-9F serial cable to connect
external serial devices to the port. The cable consists of
a 10 pin IDC connector wir ed one-to-one to a DB-9
connector . L ine 10 is simply cut off. The pin ou t is
designed so it plugs directly into the 9 pin serial port
c o nn e ct or o n a P C .
COM 0 is normally used for program ming. D uring run
time it ma y be used as a genera l purpose serial por t.
W h e n u s ed f or p r og r a m mi ng o r w i th th e IN P U T
statemen t, it acc epts ASC II chara cter value s from 0 to
127. When used with the GET function, it will return
ASCII values from 0 to 255.
COM 0 does not have handshaking lines.
RPBASIC-52 Programm ing Manual difference
CON FIG BAU D 0, 0 does not output 38,400. W hen a
baud code 0 is entered, the rate will be 57,600.