555 timer causing PIC to reset - Page 2 - Electronic Circuits Projects Diagrams Free

gabeNC · 26th May 2009, 06:11 PM

Thanks everyone for their replies. It is much appreciated.

Sceadwian · 26th May 2009, 06:14 PM

Oh I know eric, I just wanted to make sure he was actually putting them in, not just thinking the big electrolytic on the 555 alone was going to solve the problem. Sorry if I seemed like I was trying to butt heads =)

ericgibbs · 26th May 2009, 06:19 PM

Quote:

Originally Posted by Sceadwian

Oh I know eric, I just wanted to make sure he was actually putting them in, not just thinking the big electrolytic on the 555 alone was going to solve the problem. Sorry if I seemed like I was trying to butt heads =)

It would be good if gabe lets us know how it goes.

gabeNC · 26th May 2009, 06:24 PM

I've got a large 200volt 2800uf cap from an old UPS... would that keep the LED's from dimming?

I'm kidding

I'll let you guys know how it goes.

Sceadwian · 26th May 2009, 06:36 PM

Hey seriously if it fits throw it on <smirk> Just watch out for the brownout from the intial charging current =) Every time I plug an ATX supply in the lights in my house dim, biiiiig primary buffer caps.

Mr RB · 27th May 2009, 05:19 AM

You could put a 1/2 second startup delay in the PIC code, it's generally a good idea for a lot of circuits. That way if something causes a PIC reset you will see a very obvious 1/2 second pause.

gabeNC · 29th May 2009, 10:43 PM

Alrighty gents I finally got around to slapping some big caps on this circuit because I'm hooking it up to my 3 phase mains in my barn and right now i'm about to flip the swit%+@$%&

[NO CARRIER]

gabeNC · 30th May 2009, 03:16 PM

added a 470 to the input side of the 7805, a 10 to the output side a couple of 10uf tantalum caps to the PIC and a 470 close to the 555 timer.

changed the code in the pic to flash the decimal point twice before the loop (which counts from 0-9) and everything is working well, no random restarts and the seven seg is quite a bit brighter than before. I wonder if is also has to do with the different PIC on the breadboard. Went from a 876a to a 877. I can't program the first one anymore, might have fried something. With no decoupling caps, guess i'm not surprised.

thanks for all the help gents!

Hero999 · 30th May 2009, 06:12 PM

Why are you using a 555 as well as a PIC?

Can't you program the PIC to flash some LEDs as well?

gabeNC · 31st May 2009, 01:04 AM

yup... you're right. I was playing with a 555 at some point and just left it on the breadboard. Just messin' around. But having it on there, did help me to learn something practical with decoupling caps.

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26th May 2009, 06:11 PM	#16
gabeNC	Thanks everyone for their replies. It is much appreciated.

26th May 2009, 06:14 PM	#17
Sceadwian	Oh I know eric, I just wanted to make sure he was actually putting them in, not just thinking the big electrolytic on the 555 alone was going to solve the problem. Sorry if I seemed like I was trying to butt heads =) __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."

26th May 2009, 06:24 PM	#19
gabeNC	I've got a large 200volt 2800uf cap from an old UPS... would that keep the LED's from dimming? I'm kidding I'll let you guys know how it goes.

26th May 2009, 06:36 PM	#20
Sceadwian	Hey seriously if it fits throw it on <smirk> Just watch out for the brownout from the intial charging current =) Every time I plug an ATX supply in the lights in my house dim, biiiiig primary buffer caps. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har." Last edited by Sceadwian; 26th May 2009 at 06:37 PM.

27th May 2009, 05:19 AM	#21
Mr RB	You could put a 1/2 second startup delay in the PIC code, it's generally a good idea for a lot of circuits. That way if something causes a PIC reset you will see a very obvious 1/2 second pause.

29th May 2009, 10:43 PM	#22
gabeNC	Alrighty gents I finally got around to slapping some big caps on this circuit because I'm hooking it up to my 3 phase mains in my barn and right now i'm about to flip the swit%+@$%& [NO CARRIER]

30th May 2009, 03:16 PM	#23
gabeNC	added a 470 to the input side of the 7805, a 10 to the output side a couple of 10uf tantalum caps to the PIC and a 470 close to the 555 timer. changed the code in the pic to flash the decimal point twice before the loop (which counts from 0-9) and everything is working well, no random restarts and the seven seg is quite a bit brighter than before. I wonder if is also has to do with the different PIC on the breadboard. Went from a 876a to a 877. I can't program the first one anymore, might have fried something. With no decoupling caps, guess i'm not surprised. thanks for all the help gents!

30th May 2009, 06:12 PM	#24
Hero999	Why are you using a 555 as well as a PIC? Can't you program the PIC to flash some LEDs as well? __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

31st May 2009, 01:04 AM	#25
gabeNC	yup... you're right. I was playing with a 555 at some point and just left it on the breadboard. Just messin' around. But having it on there, did help me to learn something practical with decoupling caps.