Need help with a simple logic switch...

Hi Mike
In your code you wrote:
btfsc swnew,0 ; RA0 on? no, skip, else |00
call off_mode ; |00

btfsc swnew,1 ; RA1 on? no, skip, else |00
call man_mode ; |00

btfsc swnew,2 ; RA2 on? no, skip, else |00
call auto_mode ; |00

goto loop ; |00
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Don't we want to Test for High and Branch out on LOW?
btfss .....
call Off_Mode


Edit: for common anode configuration that is...

Hi Rom.

Hope you and family are well, Sir.

I apologize for my fancy example. I just threw it together quickly to test the "active low switch/active high LED" circuitry.

May I ask what your Off_Mode, Man_Mode, and Auto_Mode sub-routines do, please?

Cheerful regards, Mike McLaren (Michigan, USA)

Mike - K8LH said:

Hi Rom.

Hope you and family are well, Sir.

I apologize for my fancy example. I just threw it together quickly to test the "active low switch/active high LED" circuitry.

May I ask what your Off_Mode, Man_Mode, and Auto_Mode sub-routines do, please?

Cheerful regards, Mike McLaren (Michigan, USA)

Click to expand...

Hi Mike
Family and I are fine. Thank you for asking. Hope all is well with you.
All 3 modes implement a specific sequence of ON, OFF, and Flashing of LED's on PORTB (all Outputs).
Man_Mode and Aut_Mode also utilize PORTA: 6,7 for Outputs, and A0-3 as Inputs for Switch reads with LED attached. In this case Common Anode configuration if the logic works.
1 Switch is sliding 3 position:SP3T
And the other Switch is sliding 2 Position: SPDT (On/Off)

Regards,
Rom

jpanhalt said:

I believe that Port A is all Schmitt Trigger. The microchip switching levels are 0.2 and 0.8 x VDD .

Have you considered putting a relatively high value resistor (10 k to 50 k) in parallel with the diode or diode/resistor. That will ensure a positive pull-down without the diode drop without greatly affecting the on current available..

John

Click to expand...

I think I am going to try your suggestion before tearing my proto board apart. It is rather simple add-on fix. If I get logic zero in common cathode, I am good to go. Thanks John.
I will post again once I had a chance to test it.

Success. I added 3, 10k resistors between each pic port and ground in the common cathode configuration. No problems.
It works perfectly. In this manner, I don't need to modify my pcb much. I just add a 5pin resistor network bus to ground (in parallel to LED's) and I am good to go. I also added a 20ms delay code in my SW-Test routine to avoid any possible switch bouncing. Thanks everyone for your assist as always.
Cheers, Rom