Post by thread:need help for RTCC

<x-flowed>All, i am doing an experiment, using RTCC as an input counter from a push button, and output to a 7-segment LED. the problem is when i push the input button, i can't see any increment from the display. but it does increase the count when everytime my finger touch the input pin or wire, or pull out the input wire and insert back to the board and push the button. i have no idea what happened to this, anyone can help me, thank you! for the "option" function i set it as "3Fh", ic=pic16x55, Xtal=8 MHz. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com </x-flowed>

You might try to decouple the circuit. Use a .1uF cap evey 2'' in both directions on the board. Also a finger touch or probe touch to a circuit causes a response by the circuit because you or the probe are close to ground and when the circuit is touched the current and voltage values can change. Try the decoupling and simulate the code on MPLAB. Scott hanjay chen wrote: {Quote hidden}> All, > i am doing an experiment, using RTCC as an input counter from a push > button, and output to a 7-segment LED. the problem is when i push the input > button, i can't see any increment from the display. but it does increase the > count when everytime my finger touch the input pin or wire, or pull out the > input wire and insert back to the board and push the button. i have no idea > what happened to this, anyone can help me, thank you! > for the "option" function i set it as "3Fh", ic=pic16x55, Xtal=8 MHz. > > ______________________________________________________ > Get Your Private, Free Email at http://www.hotmail.com

Can you tell us how the input circuit's set up? (I'm suspecting something like no pull-up resistor, do you have a resistor pull-up to Vcc then the switch to ground or something?) If that resistor's not there, you get "unexpected" results (I think I just haven't remembered your circuit from earlier <G> Spend today fixing phone lines in rain & wind, a little tired.) Decoupling definitely, if a pull-up's there <G> Mark Scott wrote: > > You might try to decouple the circuit. Use a .1uF cap evey 2'' in both > directions on the board. Also a finger touch or probe touch to a circuit caus es {Quote hidden}> a response by the circuit because you or the probe are close to ground and whe n > the circuit is touched the current and voltage values can change. Try the > decoupling and simulate the code on MPLAB. > > Scott > > hanjay chen wrote: > > > All, > > i am doing an experiment, using RTCC as an input counter from a push > > button, and output to a 7-segment LED. the problem is when i push the input > > button, i can't see any increment from the display. but it does increase the > > count when everytime my finger touch the input pin or wire, or pull out the > > input wire and insert back to the board and push the button. i have no idea > > what happened to this, anyone can help me, thank you! > > for the "option" function i set it as "3Fh", ic=pic16x55, Xtal=8 MHz. > > > > ______________________________________________________ > > Get Your Private, Free Email at http://www.hotmail.com -- I do small package shipping for small businesses, world-wide.

<x-flowed>>Can you tell us how the input circuit's set up? (I'm suspecting >something like no pull-up resistor, do you have a resistor pull-up to >Vcc then the switch to ground or something?) If that resistor's not >there, you get "unexpected" results (I think I just haven't remembered your >circuit from earlier Mark THANK YOU MARK! I didn't put any resistor btw Vcc and input switch at the first time, after you told me, i tried. here was how i wired the input switch. GND--> Push button switch-->RTCC pin(#1) Second Time: GND--> Push button switch ==> RTCC/22kohm -->Vcc(+5V) Result is: still the same.... :( , it doesn't count, and only count when my finger touches the lead(RTCC). I also found, when i hold the lead(RTCC input wire) it counted so fast and the light so dim almost couldn't see from the 7-Segment LED, and i didn't push the input button only hold the lead(RTCC). Is there anything wrong, can anyone tell me where i did wrong at the input circuit. Thank You Very Much!!! Tools i am using: PIC-ICE for PIC 16XX >Scott wrote: > > > > You might try to decouple the circuit. Use a .1uF cap evey 2'' in >both directions on the board. Dear Scott, I am using a breadboard for the wiring, can u help me how to decouple the circuit and both directions, and i am not kinda lost here. Thank You for your help!!! Also a finger touch or probe touch to a circuit causes {Quote hidden}> > a response by the circuit because you or the probe are close to ground >and when > > the circuit is touched the current and voltage values can change. Try >the > > decoupling and simulate the code on MPLAB. > > > > Scott > > > > hanjay chen wrote: > > > > > All, > > > i am doing an experiment, using RTCC as an input counter from a >push > > > button, and output to a 7-segment LED. the problem is when i push the >input > > > button, i can't see any increment from the display. but it does >increase the > > > count when everytime my finger touch the input pin or wire, or pull >out the > > > input wire and insert back to the board and push the button. i have no >idea > > > what happened to this, anyone can help me, thank you! > > > for the "option" function i set it as "3Fh", ic=pic16x55, Xtal=8 >MHz. ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com </x-flowed>

It sounds as though the RTCC is counting or at least reacting to mains hum on your finger. In that case, could I suggest the obvious, that is, get the multimeter out and check all wire and components. Have you actually measured Vcc voltage on RTCC ? It would seem the pin is floating. Jinx > Second Time: > GND--> Push button switch ==> RTCC/22kohm -->Vcc(+5V) > > Result is: still the same.... :( , it doesn't count, and only count when my > finger touches the lead(RTCC). I also found, when i hold the lead(RTCC input > wire) it counted so fast and the light so dim almost couldn't see from the > 7-Segment LED, and i didn't push the input button only hold the lead(RTCC). > Is there anything wrong, can anyone tell me where i did wrong at the > input circuit. Thank You Very Much!!! > > Tools i am using: PIC-ICE for PIC 16XX

BTW, you say you can hold the lead on RTCC. How long is it ? Jinx > Second Time: > GND--> Push button switch ==> RTCC/22kohm -->Vcc(+5V) > > Result is: still the same.... :( , it doesn't count, and only count when my > finger touches the lead(RTCC). I also found, when i hold the lead(RTCC input > wire) it counted so fast and the light so dim almost couldn't see from the > 7-Segment LED, and i didn't push the input button only hold the lead(RTCC). > Is there anything wrong, can anyone tell me where i did wrong at the > input circuit. Thank You Very Much!!! > > Tools i am using: PIC-ICE for PIC 16XX