What can reset PORTx ?

ericgibbs · Sep 13, 2009

I have one 16F877A circuit already built, I could reprogram the PIC and link it to my PC via the RS232. I will get back to you later today.

hi,
Programmed a 16F877 [dont have a A ver] with your program.
I have set the RS232 PC to 19200 baud and assumed a 4MHz xtal.

Linked via MAX232 to my PC, using a RS232 utility prog I can send single bytes to the PIC and see the LED's ON or OFF, as set by the byte value.

The LED's are steady without any flashing.

I will look again later...

be80be · Sep 13, 2009

What value is them 14 resistors
14 x20ma = 280
I've made led cubes that would run fine for a day and after that the chip would shut down
it would be hot to touch let it cool and on it would go agin.

AtomSoft · Sep 13, 2009

Burt that makes sense. Im just counting all the reasons to stock up on ULN2803 ICs

ericgibbs · Sep 13, 2009

be80be said:
What value is them 14 resistors
14 x20ma = 280
I've made led cubes that would run fine for a day and after that the chip would shut down
it would be hot to touch let it cool and on it would go agin.

Interesting theory Burt, but there are only 7 LED's per PIC, so for 10mA/LED thats only 70mA or 140mA tops.

Look at the video the flashing rate is far faster than the heat/cool cycle.

be80be · Sep 13, 2009

ericgibbs said:
Interesting theory Burt, but there are only 7 LED's per PIC, so for 10mA/LED thats only 70mA or 140mA tops.

Look at the video the flashing rate is far faster than the heat/cool cycle.

This is from the OP

14 - LED and 14 resistors for LED (For PORTA and PORTB)

ericgibbs · Sep 13, 2009

be80be said:
This is from the OP

Look at the vid, its quite short.

I think its a language problem Burt, there are only 7 leds on PORTA.

be80be · Sep 13, 2009

PIC2PIC said:
Is it possible to someone build the same circuit, to check if I am wrong. Its really simple.

One need :
2 -16f877
14 - LED and 14 resistors for LED (For PORTA and PORTB)
2 - chrystal
4 - 27 pF capacitors
Supply stable 5 V.

Just put LED and resistors on PORT/A/B. Connect what must one for PICs, set the program, connect two PICs . And that's it.

That came from his post and not mine
And you think a pic can sink or source 20 to 25ma That is wrong what the data sheet tells you that's the max for one pin

Not a port of pins

In real life it's more like 50ma for the whole port

If you read the data sheet it tells you that the chip can have a combined
usage of 200ma for all ports Pop that by 5 and see what you get or 4 to make you fell better

gaspode42 · Sep 13, 2009

Originally Posted by PIC2PIC View Post
Is it possible to someone build the same circuit, to check if I am wrong. Its really simple.

One need :
2 -16f877
14 - LED and 14 resistors for LED (For PORTA and PORTB)
2 - chrystal
4 - 27 pF capacitors
Supply stable 5 V.

Just put LED and resistors on PORT/A/B. Connect what must one for PICs, set the program, connect two PICs . And that's it.

Yes but that is two make two sets - one for each side, so 7 LED's per PIC

PIC2PIC · Sep 13, 2009

Hi

No, supply is not the problem. Because I have :

PIC1 - uses only PORTA - 6 LEDs and all resistors are 1 Kohm, and no other LED

PIC2 - uses only PORTB - 8 LEDs and all resistors are 1 Kohm, and no other LED

PIC2PIC · Sep 13, 2009

Yes, WDT is disabled.

birdman0_o · Sep 13, 2009

If you have enough transistors, try using them. Otherwise I will test your code tonight I have a bunch of 887a's.

be80be · Sep 13, 2009

PIC2PIC said:
Hi

No, supply is not the problem. Because I have :

PIC1 - uses only PORTA - 6 LEDs and all resistors are 1 Kohm, and no other LED

PIC2 - uses only PORTB - 8 LEDs and all resistors are 1 Kohm, and no other LED

Thanks for letting us know what size resistor is pulling mclr to vdd to low value
can cause reset.

PIC2PIC · Sep 13, 2009

MCLR is directly connected to Vdd

PIC2PIC · Sep 13, 2009

People thank you all. You are very kind.
I am working on this for weeks ... It comes to me broke all this electronics sh.t and to f..k all PIC and take a hammer and smash all hardware and stop all sh..ing on programing and put all this crap to garbage and make all electronics kiss my ass and all transistors and capacitors and and ...

be80be · Sep 13, 2009

PIC2PIC said:
MCLR is directly connected to Vdd

Thats whats resetting your pic put a 20 k resistor from mclr to volts vdd
with out it your chip can latch-up or reset

PIC2PIC · Sep 13, 2009

@be80be

I try putting 18 kohm resistors from MCLR to Vdd. No, is not working, same blinking.

be80be · Sep 13, 2009

I ran the code you posted and mike formatted it blinks the leds on portb

birdman0_o · Sep 13, 2009

PIC2PIC said:
People thank you all. You are very kind.
I am working on this for weeks ... It comes to me broke all this electronics sh.t and to f..k all PIC and take a hammer and smash all hardware and stop all sh..ing on programing and put all this crap to garbage and make all electronics kiss my ass and all transistors and capacitors and and ...

It will come with time! Patience my friend!

be80be · Sep 13, 2009

birdman0_o said:
It will come with time! Patience my friend!

I remember the first hard code I did It was the sony remote code Nigel did I wanted to use it on a 12f675 it took a month to get it to work right. I could do the same thing now in a hour LOL

ericgibbs · Sep 14, 2009

be80be said:
That came from his post and not mine
And you think a pic can sink or source 20 to 25ma That is wrong what the data sheet tells you that's the max for one pin

Not a port of pins

In real life it's more like 50ma for the whole port

If you read the data sheet it tells you that the chip can have a combined
usage of 200ma for all ports Pop that by 5 and see what you get or 4 to make you fell better

hi,
We seem to be getting our wires crossed.
Where does it say on the OP's posts he is running each of the 7 leds at 20mA.??

This blinking problem as I understand also occurs when not all 7 are in use.

I am aware of what the datasheet says regarding the current sink/source.
Refer image.

I am puzzled why you seem to be taking this as personal attack rather than a technical discussion.

What can reset PORTx ?

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