Remain counting while sending out a pulse

[ultiblade]

Hi there,
I'm learning a lot just browsing this forum, but i'm quite stuck at the moment.
What i'm trying to do is the following :

I'm have to build a puls divider. When a jumper is on pin 4(gpio3), it counts a number of pulses on pin 5(gpio2), when the jumper is taken off it divides the number of pulses that were count by 10 and stores that in eeprom.

It then returns to it's normal routine, counting the pulses. If, say 500 pulses have been counted it must output one 50ms pulse every 50 pulses (500/10=50).

The problem is that im using pulsout plsout,5000 for the pulse output, but this delays the counting of the pulses with 50ms. Which results in me missing some of the incoming pulses.

Is there anything i can do to keep counting and give a command to make the pin high for 50ms ??


'——-[ Device Initialization ]————————————————————————————————————
@ device pic12F635,intrc_osc_noclkout,wdt_off,pwrt_off,mclr _off,bod_off,cpd_off,protect_off

'==== Variables ======================================

INCLUDE "modedefs.bas"
DEFINE OSC 4

plsOUT var GPIO.0
plsIN var GPIO.2
LEARN var GPIO.3
ser var GPIO.1

i var word
tel var word
div var word

output plsOUT
output ser
input plsIN
input LEARN

i=0
tel=0
div=0

pause 1000

main:
if learn = 1 then goto reset

read 1,i.lowbyte
read 2,i.highbyte
pauseus 50
div = i/10

pl1:
if i = 0 then goto reset
if plsin = 1 then
tel = tel + 1
'Serout ser,T9600,[#tel,45,#i,45,#div,13,10]
if tel >= div then
pulsout plsout,5000
tel = 0
else

goto pl0
endif
pl0:
if learn = 1 then goto reset
if plsin = 1 then
PAUSEUS 50
GOTO PL0
else
goto pl1
endif
else
goto PL1
endif
if learn = 1 then goto reset
goto pl1

reset:
i=0
tel=0
div=0

np:
if learn = 1 then
if plsin = 1 then
i = i+1
goto wp
else
goto np
endif
wp:
if learn = 1 then
if plsin = 0 then
goto np
else
goto wp
endif
else
write 1,i
goto setmem
endif
else
goto setmem
endif
goto main

setmem:
if i = 0 then goto np
write 1,i.lowbyte
write 2,i.highbyte
pauseus 50
setmem2:
if learn = 0 then
goto main
else
goto setmem2
endif

theend:
goto theend

[HenrikOlsson]

Hi,
I'd sugest you set up the TMR1 module as an asychcronous counter and feed your pulses to Pin2. The timer module will then count the pulses for you and you can read/reset/preset the count any time you like. The timer will keep on counting no matter what the rest of program is doing. Have a look at section 6 in the datasheet.

/Henrik Olsson.

[ultiblade]

Hi Henrik, thanks for replying !

I have looked at section 6 in the datasheet. Do you have some sample code
on how to setup pin 2 as an asychcronous counter ?

Is the counter able to put it's "number of pulses count" into a variable ?

I have got no clue on how to implement this within my code ...

Thanks in advance !

[HenrikOlsson]

Hi,
First you need to set GP5 as an input. Then you set the function of the TMR1 module using the T1CON register. The value of the TMR1 module is can be read/written from/to using TMR1H and TMR1L register.

Here's a shot at it (untested):


TRISA.5 = 1 'Set GP5 to input.

Count Var Word
Temp var byte

'Set TMR1 to increment on rising edge of T1CKI pin, no prescaler, no sync to internal clock, TMR 1 is on.
T1CON = %00000111

Loop:
Count.highbyte = TMR1H 'Get high byte of counter
Count.Lowbyte = TMR1L 'Get low byte of counter


'Make sure that the counter did not roll over between reads of the high and low byte.

Temp var TMR1H 'Get highbyte again.
If Temp - Count.HighByte <> 0 then 'The two values differs so we read it again.
Count.HighByte = TMR1H
Count.LowByte = TMR1L
ENDIF

Serout ser,T9600,[#Count,13,10] 'Send count to computer.
Pause 100
Goto Loop


As I said - not tested but should be close to what you want.

(Edit)
Oh..I forgot...
You can stop counting by setting bit0 of T1CON to 0, start again by setting it to 1 and you can set the TMR1H and TMR1L register to what ever you want by writing to them just like any other variable.

/Henrik Olsson.

[ultiblade]

Henrik ! Wow !

Compiled your code, and it counts great !
Many thanks for getting me started !

[HenrikOlsson]

Hi,


Compiled your code, and it counts great !

Woohoo....I don't think that has ever happend to me before..... :-)
You're welcome!

/Henrik Olsson.