59
Communications Errors
Section 4-6
Port #2: SCRN or LPRT
4-6
Communications Errors
When a communications error occurs while a BASIC program is being exe-
cuted, the ERR1 or ERR2 indicator on the ASCII Unit will be lit and at the
same time the CPU Unit’s port 1/2 error flag (bit 04/05 of word n+5) will be
turned ON (be set to 1). Execution of the BASIC program will continue. If the
ON ERROR command has been used in the BASIC program, the program will
be diverted to the specified interrupt subroutine when a communications error
occurs.
If another error occurs during the execution of the error interrupt subroutine
however, the BASIC program will stop executing (regardless of whether the
error affects the error subroutine). If the following situation is likely, program
execution may be stopped, so be careful when using the ON ERROR com-
mand. Alternatively, do not use the ON ERROR command in a situation like
the one below, where execution of the BASIC program should be continued
even if a communications error occurs.
• Other errors occur during an interrupt subroutine due to communications
errors.
Note ON ERROR Command
The ON ERROR command is used for processing with other errors, so it will
be necessary to use the IF-type statements for processing. When error pro-
cessing is complete, use the RESUME command to return to the origin of the
diversion and continue processing. Error status can be cleared after error pro-
cessing is complete by using the ERC command.
CTS
CTS_ON
No check
No check
Check
No check
No check
(during send)
CTS_OFF
No check
No check
No check
No check
No check
DSR
DSR_ON
No check
No check
Check
No check
No check
DSR_OFF
No check
No check
No check
No check
No check
Command
Mode
Open
Receive data
Send data
Close
OFF
RTS_OFF
ON
RTS
RTS_ON
ON
RUN
Command
Mode
OFF
DTR
ON
OFF
None
None
Status depends on DTR command
Summary of Contents for C200H-ASC11
Page 1: ...C200H ASC11 ASC21 ASC31 ASCII Units Operation Manual Revised June 2000...
Page 2: ...iv...
Page 4: ...vi...