Radio Shack TRS-80 PC-2 - Page 9

• Enhancements to BASIC not related to communica-
tions. These commands are not directly related to
communications functions but they do add power and
flexibility to the existing PC-2 BASIC language.
•
Enhancements to BASIC related to communications.
This group of commands allows BASIC to interact
with external devices, utilizing the RS-232 communica-
tions hardware.
• Terminal Mode Commands. These commands allow
you to configure and control the machine-language
smart Terminal Program.
In this section, we'll describe all of the BASIC Mode
commands first. These will be listed in alphabetical order
for your convenience.
Control and Status Commands
Control and status commands provide control over various
RS-232C
protocols and configurations. All are imple-
mented as new BASIC commands.
Since the RS-232C Interface lets you control many types
of input and output devices, we'll use the following
abbreviations when referring to them. See Table 2.
KI
--
Keyboard Input
DO
--
Display Output (LCD)
PO
--
Printer Output
CI
--
Cassette Input
CO
--
Cassette Output
Table 2
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CLOADa
Load an ASCII Format Program from RS-232C
CLOADa
CLOAOa reads an ASCII format program from the RS-
232C. This means:
• Each line must start with a line number.
• Each line is ended with a carriage return (DOH).
•
Maximum length of line is 160 characters, including
line
number and the carriage return.
• Leading blanks (after a carriage return and before a
line
number) are ignored.
• File
is ended with a null line (carriage return only).
• After compression, a maximum of 80 bytes are
allowed.
CLOAOa functions only when the cassette input is routed
from the RS-232C. Except for its characteristic of read-
ing
the program in ASCII format, it functions identically
to CLOAO.
It should be noted that the sending device must pause two
seconds between lines (after each carriage return) to allow
BASIC time to insert the new line into memory.
To load a program in ASCII format through the RS-232C,
use
the following sequence:
SETDEV CI
CLOADa
Note: A program loaded via CLOADa must not contain
the Pi symbol or the square root symbol within quoted
text.
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