Remote-processing RPC-330 Manuel d'utilisateur télécharger pdf (Page 44)

MULTI-MODE COUNTER SECTION 13

Page 13-2 RPC-330

short pulse is generated. The latch captures it captures

it. A latch is cleared using LINEB function.

500 A = LINEB(6,5) :REM clear counter 0 latch

510 A = LINEB(6,7) :REM clear counter 1 latch

Clear a latch befor e it is used as an inter rupt.

Program examples

This code resets counter 0 and enables its inputs. The

count is printed once a second. To see the count change,

momentarily bring "A0 IN" or "B0 IN" on P2 to ground.

When "B0 IN" is gr ounded, the count decrem ents.

10 LINEB 6,1,32

20 LINEB 6,1,64+8

30 ONTICK 1,500

40 GOTO 40

500 PRINT COUNT(0)

510 RETI

Line 20 can be shortened somewhat. 64 selects the ICR

(Input control register ) and 8 enables inputs. 72 could

have been used.

The following program example returns a frequency.

Input signal is at "A0 IN".

100 LINEB 6,1,32

110 LINEB 6,1,72 : REM enable inputs

120 ONTICK 1,500

130 IDLE

140 GOTO 130

500 A=COUNT(0) : REM get count

510 C=A-B : REM figure change from last time

520 PRINT "Frequency = ",A

530 B=A

530 RETI

The first frequency read will always be a bit off. This is

because of the time required to initialize ONTICK.

Subsequent readings are more accurate.

Accuracy is increased by stretching ONTICK to every

10 seconds. This is necessary when higher accura cy is

needed.

Other factors affecting accurate readings in this program

include serial comm unications and ONIT R statement.

A problem with this routine is periodically, a large

negative number is returned. This is because the

multimode counter has rolled over. This is corrected by

periodically resetting the CNTR or transfer ring P R to

CNTR. Refer to the data sheet, Appendix A for counter

operating modes.

The next program sets up the LS7166 to cause an

interrupt when a preset number of counts (100) is

reached. H2[3-4] is jumpered to interrupt on a borrow.

10 LINEB 6,1,132

20 COUNT 0,100 : REM write to CNTR

30 LINEB 6,1,8 : REM transfer PR to CNTR

40 LINEB 6,1,72 : REM enable A/B counters

50 ONITR 0,500

100 PRINT COUNT(0) : REM print progress

110 GOTO 100

500 PRINT "In Interrupt"

510 RETI

Line 10 sets OCCR to divide by N. Line 50 enables

INT 0 interrupt. Line 100 prints the counter. W hen

pulses are applied to the A input, the count will go

down. W hen 100 pulses are detected at A input, the

message in line 500 is printed.

To use INT 1, jumper H3[3-4] and change the LINEB

address to 3. Change references to count and INT to 1.

This next example interfaces to a quadrature encoder in

x1 mode. An interrupt is generated when the counter

crosses 0. Jumper H2[9-10] for INT0 and H3[9-10] for

INT1. The program below is for counter 0. Set

variable B to 3 and C to 1 for counter 1 in line 5.

The counter is pre-loaded to 150. W hen the enco der is

turned so the count goes down to 0, an interr upt is

generated.

5 B = 1 : C=0

10 LINEB6,B,32 : REM master counter reset

20 LINEB6,B,128 : REM set CYBW active

30 LINEB6,B,193 : REM enable quadrature x1 mode

40 LINEB6,B,72 : REM enable a/b counters

60 COUNTC,150 : REM load PR with 150

70 LINEB 6,B,8 : REM load PR into count reg

80 A=LINEB(6,B+4) : REM reset interrupt latch

100 ONITR C,500 : REM set up interrupt

110 ONTICK .5,1000 : REM print out COUNT

120 GOTO 120

500 PRINT "Interrupt count",COUNT(C)

510 A = LINEB(6,B+4) :REM Reset int. latch

520 RETI

1000 PRINT COUNT(C)

1010 RETI

1 2 ... 39 40 41 42 43 44 45 46 47 48

Commentaires sur ces manuels

Pas de commentaire

Remote-processing RPC-330 Manuel d'utilisateur Page 44

Commentaires sur ces manuels

Produits connexes et manuels pour Ordinateurs Remote-processing RPC-330