Displaying temperature Setpoints

[Kalind]

just want to apologise for asking too much. i manage to get the thing working. just have to try tweak here and there...

[skimask]

just want to apologise for asking too much. i manage to get the thing working. just have to try tweak here and there...

And what ended up fixing the problem?

[Kalind]

well, the button where connected incorrectly. that being my partners fault. also a few things in the program which where so obvious.. now im gona add in buzzer for high/low and also relays to switch loads at certain temps.

[Kalind]

BIG PROMLEM!!! After adding on all the extra's (relay code, leds...etc), the pic is operating at snails pace!!! What do i do about this now??

[mackrackit]

BIG PROMLEM!!! After adding on all the extra's (relay code, leds...etc), the pic is operating at snails pace!!! What do i do about this now??

Did you DEFINE the OSC or mes with the configs?

Post you code so we can take a look.

[Kalind]

im using a 4mhz crystal oscillator. I did define it in ADCON0. Bit 6-7 as 11. i would also like to know what difference would there be if i had to amplify the output signal from the LM35. and if i did, please explain to me whether i'd be getting more accurate results? N.B. 16F873

Define LCD_DREG PORTB
Define LCD_DBIT 0
Define LCD_RSREG PORTB
Define LCD_RSBIT 5
Define LCD_EREG PORTB
Define LCD_EBIT 4
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2

mode var byte
keyin var byte
adval var word
tempc var word
highpt var byte
lowpt var byte
highled var porta.1
lowled var porta.2
relayhigh var porta.3
relaylow var porta.4
buzzer var porta.5
up var portc.0
down var portc.1
sethighp var portc.2
setlowp var portc.3
maindisp var portc.4
highpt = 100
lowpt = 0
trisc= %00011111
trisa=%00000001
adcon1=%11110010
adcon0=%11000001

pause 100

lcdout $fe , 1
mode = 1
goto main

getkey:
pause 50
keyin = portc
return

gettemp:
adcon0.2=1
pause 1

checkdone:
if adcon0.2=1 then checkdone

adval.highbyte=adresh
adval.lowbyte=adresl

tempc=50*adval
tempc=tempc/100

If tempc>=highpt then
gosub high_flash
SOUND buzzer, [60, 100, 23, 200]
relayhigh = 1
else
relaylow = 0
lowled = 0
buzzer = 0
endif

If tempc<=lowpt then
gosub low_flash
SOUND buzzer, [20, 100, 23, 200]
relaylow = 1
else
relayhigh = 0
highled = 0
buzzer = 0
endif

return

main:
gosub gettemp
gosub getkey

if maindisp = 0 then mode = 1
pause 50
if sethighp = 0 then mode = 2
pause 50
if setlowp = 0 then mode = 3
pause 50

select case mode

case 1
write 0 , sethighp
pause 10
write 1 , setlowp
lcdout $fe , 1
Lcdout "TEMP = ",DEC tempc,$DF,"C"

case 2
lcdout $fe , 1
lcdout $fe , $80 , "High Setpoint:" , $fe , $c0 , dec highpt, $DF , "C"
if up = 0 then highpt = highpt + 1
if down = 0 then highpt = highpt - 1
if highpt>100 then highpt=0

case 3
lcdout $fe , 1
lcdout $fe , $80 , "Low Setpoint:" , $fe , $c0 , dec lowpt, $DF , "C"
if up = 0 then lowpt = lowpt + 1
if down = 0 then lowpt = lowpt - 1
if lowpt>100 then lowpt=0
end select
goto main

high_flash:
HIGH highled
PAUSE 350
LOW highled
PAUSE 350
RETURN

low_flash:
HIGH lowled
PAUSE 350
LOW lowled
PAUSE 350
RETURN

[mackrackit]

im using a 4mhz crystal oscillator. I did define it in ADCON0. Bit 6-7 as 11. i would also like to know what difference would there be if i had to amplify the output signal from the LM35. and if i did, please explain to me whether i'd be getting more accurate results? N.B. 16F873

You define the oscillator

DEFINE OSC 4

but PB defauts to 4 so you should be good there.

The LM35 does not need amplification. If it is giving a fluctuation on the reading a capacitor between the signal and 0 volts (ground) will fix that.

Still looking through you code...
When it gets to the LED blinking, do they blink at the correct speed? Or are you seeing slow running some place else?