Remote-processing RPC-210 Manuel d'utilisateur télécharger pdf (Page 42)

EXTERNAL INTERRUPTS SECTION 9

Page 9-2

Line 10 sets up the operating system to process interrupt

0. Lines 20 and 30 increment a counter used by the

interrupt subroutine. When INT 0 goes low, code

starting at line 500 is executed as soon as the current

RPBASIC-52 statement is finished (usually in 1 mSec).

RETI is necessary to allow other interrupts. However,

if INT 0 remains low, the interrupt program will be re-

executed starting at line 500 as soon as R ETI is

executed. To prevent this, try to reset the cause of the

interrupt. If this is not possible, then execute

550 ONITR 0

This will disable INT0. You can monitor this line by

tying it to a free input at J3 and use ON LINE to detect

when it is high again.

Interrupt Priority

INT 0 is second only to ONTICK If an ONTICK

program is exec uting, an ONITR r outine is delayed until

ONTICK is finished. ONIT R cannot be interrupt by any

other multi-tasking routine such as ON COM$, ON

LINE, etc.

APPLICATION PROGRAMS

Interrupts are part of the CPU process. For setup

example, review any of the programs below.

File name Description

COUNT1.BAS Quadrature encoder input. Counter

program generates INT 0 on 0

crossing.

COUNT2.BAS Quadrature encoder input. Counter

program generates INT 0 when

preload count matches current

count.

COUNT3.BAS Pulse input. Interrupt when count

goes through 0.

RTC-5.BAS Interrupt at preset hour, minute,

and/or second.

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 59 60

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Remote-processing RPC-210 Manuel d'utilisateur Page 42