Problems with hysteresis as soon the ADC reaches 255

[msmax]

Need help with PIC asm

Please give your advise on next problem:

I read in an analogue value.
I like to switch 4 outputs on predefined levels.

Problem is that the output is blinking very fast as soon as the ADC reaches the prefined levels before it goes on steady. I think some hysteresis must be added here to solve this problem.

How would you program this in assembler?

 

[C-Man]

Re: Need help with PIC asm

My answer to your problem here:
**broken link removed**

should also help you with your new problem which is nearly the same ...

best regards

 

[msmax]

Re: Need help with PIC asm

That looks stupid.

I already asked this question...
Had to ask the next:

It works as you described.
I do get some problems with this hysteresis as soon the ADC reaches 255, then it will go to 0+.

Same happens if the ADC reaches 0 and I do this comparision.

Sorry...

 

[C-Man]

Re: Need help with PIC asm

Ok what PIC are you using (8 Bit ADC or 10 Bit ADC)?

Can you post your current code?

best regards

 

[msmax]

Re: Need help with PIC asm

I use a PIC16F628 with ADC0831.

Here is part of my code:

MOVFW Alarm1
ADDLW Hysteresis
SUBWF ADCresult,W
SKPNC
BSF A1_Out

MOVFW ADCresult
ADDLW Hysteresis
SUBWF Alarm1,W
SKPNC
BCF A1_Out

Hysteresis is a constant = 1
Alarm1 is a var
ADCResult is the last read ADC value.

The ADC input value will go from 0-255 or vv.
The output should be ON if ADCresult>Alarm1
It should be OFF if ADCresult<Alarm1

Problem starts if Alarm1 is 255 or ADCresult is 255.
How to handle this?

The full unit should work as following:
We have 4 outputs: OC, BB, A1, A2
We have 5 vars: vOC,vBB,vA1,vA2,vSC

If ADC < vOC then all is off: OC status
If ADC < vBB then BB&OC is ON, others off: BB status
If ADC > vOC and ADC<vSC then OC is ON, all other OFF: Normal status
If ADC > vA1 and ADC<vSC then OC & A1 is ON, others OFF: A1 status
If ADC > A2 and ADC<vSC then OC&A1&A2 is ON, BB is OFF: A2 status
If ADC > vSC then all is OFF: SC status, same as OC status

Hope this makes clear what I like to do with this system.
Thanks for your help.