65
Interrupt Functions
Section 5-5
Note
1.
When an interrupt is generated upon receiving a specified number of char-
acters or data up to a specified character, all data is received in the receive
buffer. If the necessary number of characters is retrieved by the INPUT$
function, it is possible to use first-in/first-out (FIFO) processing to move that
group of characters to the front of the receive buffer.
2.
One of the ON, OFF, or STOP commands must be specified for the inter-
rupt as shown in the column on relevant commands. The STOP command
prevents branch processing even if the interrupt has occurred; it simply
records the interrupt entry, and branching occurs with the subsequent ON
command.
3.
Interrupts set for GOTO statements will wait until the current BASIC com-
mand has been executed.
4.
IOWR#CC00 interrupts are not accepted while the ASCII Busy Flag is ON.
Interrupt Priority
If more than one interrupt is generated at the same time, the interrupt subrou-
tines will be executed in the following order of priority.
Interrupt Priority Order Table
If further interrupts are generated during the execution of an interrupt subrou-
tine, they will be processed after execution of the current interrupt subroutine
has been completed, according to the interrupt priority order table shown
above. ON ERROR interrupts, however, will be executed immediately, even
during execution of other interrupt subroutines.
Example
If ON COM 1 and ON ALARM interrupts are generated while an ON PC1
interrupt subroutine is being executed, the ON COM1 interrupt subroutine will
be executed after the ON PC1 interrupt subroutine has been completed, as
ON COM 1 has priority over ON ALARM. After the ONCOM 1 interrupt sub-
routine has finished executing, the ON ALARM interrupt subroutine will be
executed.
If a PC interrupt subroutine is generated while the ON COM 1 interrupt sub-
routine is being executed, the PC interrupt subroutine will take priority over the
ON ALARM interrupt.
If more than one interrupt is generated simultaneously or if another interrupt is
generated while a interrupt subroutine is being executed, one interrupt will be
recorded if this status is either ON or STOP.
Order of priority
Interrupt
1
ON COM 1
2
ON COM 2
3
ON KEY 0
:
:
12
ON KEY 9
13
ON PC 1
:
:
111
ON PC 99
112
ON ALARM
113
ON TIMER
114
ON TIME$
Summary of Contents for C200H-ASC11
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