PIC16F84A Single Digit Clock coding Problems (Nixie) - Electronic Circuits Projects Diagrams Free

Suraj143 · 7th February 2007, 03:54 AM

Hi I’m building nixie’s single digit clock. the original link and the source code you can find here

http://www.electronixandmore.com/project/15.html

I made and assembled the file and ran the circuit. But I got a problem. The segment “E” is not working all the others working. Why is this?

Table for the numbers also done in a different way. Taken PORTB 2 pins & PORTA all 5pins for the segment. For the table it hasn’t use RETLW. I’m confused with it. I changed more PICS but still having the problem. So I need urgent help from you.

Thanks a lot.

**Nigel Goodwin** · 7th February 2007, 07:38 AM

You might try reading the datasheet?, RA4 is an open collector output - you need a pullup resistor to make it go high!.

Suraj143 · 8th February 2007, 05:36 AM

Quote:

Originally Posted by Nigel Goodwin

You might try reading the datasheet?, RA4 is an open collector output - you need a pullup resistor to make it go high!.

Ya thats the problem Nigel.I referred to the data sheet RA4 is open drain type.I missed that pullup resistor.Now its working.

thankx .

**Nigel Goodwin** · 8th February 2007, 07:47 AM

Quote:

Originally Posted by Suraj143

Ya thats the problem Nigel.I referred to the data sheet RA4 is open drain type.I missed that pullup resistor.Now its working.

It's a VERY, VERY, VERY common mistake! - I still do it occasionally even now!.

pasanlaksiri · 8th February 2007, 01:49 PM

Thanks friend. This info is very usefull for me also. Coz i also have same problem

**Nigel Goodwin** · 8th February 2007, 02:20 PM

Quote:

Originally Posted by pasanlaksiri

Thanks friend. This info is very usefull for me also. Coz i also have same problem

No need to thank me, you will find the same information posted all over this forum by MANY different people - like I said, it's a VERY common mistake.

It's funny, sometimes you really curse it for being different, then another day you wish all the outputs were like that! - you just can't win!

mrpicing · 8th February 2007, 06:15 PM

hi every body! we all humen makes same mistakes many times.
But i try to start with some tips. checking of powersupply, reset pin,oscilator, low voltage programming pin, and always RA4.
and Nigel Goodwin is every where in the pic forums with his excellent experties.

Have a nice day!

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7th February 2007, 07:38 AM	(permalink)
Nigel Goodwin	You might try reading the datasheet?, RA4 is an open collector output - you need a pullup resistor to make it go high!. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

8th February 2007, 01:49 PM	(permalink)
pasanlaksiri	Thanks friend. This info is very usefull for me also. Coz i also have same problem

8th February 2007, 06:15 PM	(permalink)
mrpicing	hi every body! we all humen makes same mistakes many times. But i try to start with some tips. checking of powersupply, reset pin,oscilator, low voltage programming pin, and always RA4. and Nigel Goodwin is every where in the pic forums with his excellent experties. Have a nice day!