Can't get 16F628A "If PortA.0 = 1 Then " to work

Bracer

New Member

• Aug 15, 2010

• #1

This is the Code in PICBasic Pro:

@ DEVICE pic16F628A, INTRC_OSC_NOCLKOUT 'Use Internal Clock
Input PortA.0 'Makes Port A, Pin 0 an Input.

Routine:

If PortA.0 = 1 Then
High PortB.0
Sound PortB.7, [120,15]
endif

Goto Routine

I don't understand why it doesn't react when PortA.0 IS high

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Aug 15, 2010

• #2

You need to disable the analogue comparators, they are ON by default.

 

lilimike

Member

• Aug 15, 2010

• #3

To disable:
CMCON = $07

Mike

 

Bracer

New Member

• Aug 15, 2010

• #4

Yes!
CMCON = 7

Thank you lilimike & Nigel Goodwin.

lilimike...why "CMCON = $07" ?

What's with the "$0" ?

Thanks

 

lilimike

Member

• Aug 15, 2010

• #5

The $ means the value is hexadecimal, you can also use % for binary or simply 7 for decimal.
Of course 7 = 07 but since I used HEX I always use 2 digits which are from $00 to $FF

Its just a programming habit.

Mike

 

Last edited: Aug 15, 2010

Bracer

New Member

• Aug 15, 2010

• #6

So a hexadecimal = decimal ?

because I tried CMCON = 7 and it works perfectly.

If $07 = 7, why would people use hex at all ?
Just use decimal all the way ?

 

lilimike

Member

• Aug 15, 2010

• #7

Hexadecimal from 0 to F
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

Decimal from 0 to 15
0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15

As you can see both count up to 15 and both are equal up until 9

You will get a good explanation HERE with a comparison betwen HEX, DEC and Binary

Mike

 

J

Jon Chandler

Banned

• Aug 15, 2010

• #8

A good reference covering many problems in making PICs run is here:


Commandments for Using PICs

 

A

amando96

Guest

• Aug 15, 2010

• #9

The first 9 numbers of HEX are just like HEX, to convert it mentally you also have to know binary(at least the way I do it).

 

J

Jon Chandler

Banned

• Aug 15, 2010

• #10

Commandments for Using PICs talks about some often overlooked issues that frequently cause problems.