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Breadboard and my microcontroller.

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The breadboard capacitance myth is crapola too.

How can breadboard capacitance be a myth?, it's even listed in the boards specifications.

You can't build VHF radio circuits on breadboard due to it's excessive capacitance - no myth, no crapola. I wouldn't advise doing any radio circuits on breadboard, but for audio and logic it's fine (if you like that sort of thing).
 
A while back I posted regarding building the circut up in parts, testing each part as you go. Go back and read it.

Also there is no reason it should not work on a solderless BB unless it is a old worn out one.


After more testing, I think the problem lies with the other circuitry my PIC is driving, not the PIC itself. I have (neatly) soldered the PIC onto strip board with crystal and decoupling caps.

I am doing the same with matrix driver, I'll post back later on when it's finished.
 
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After more testing, I think the problem lies with the other circuitry my PIC is driving, not the PIC itself.
Maybe post a diagram of this "other" circuitry. Or better yet, the entire schematic of the project in one graphic file.
One other thing. In your original post you state that you are clocking the shift register at 4Mhz. On your schematic your crystal is labeled as both a 20Mhz AND a 32Khz crystal. If it is a 20Mhz crystal, you should have _HS_OSC selected in config, not _XT_OSC. If it is a 32Khz crystal, then the caps may need changing to 33pf and you'll need _LP_OSC in config instead. What IS the crystal frequency anyway?
 
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How can breadboard capacitance be a myth?, it's even listed in the boards specifications.

You can't build VHF radio circuits on breadboard due to it's excessive capacitance - no myth, no crapola. I wouldn't advise doing any radio circuits on breadboard, but for audio and logic it's fine (if you like that sort of thing).
Taken in the context of the forum they were posted in, Microcontrollers, my comments were correct. Nobody here is talking about building VHF radio circuits. :p
 
Is this a bad idea? I've noticed my PIC16F877A is pulling a lot of current, voltage regulator is struggling to say the least (It's a LM7805). The PIC is driving an 8 bit shift register which is connected to LEDs through a 100ohm resistor.

The output pin is right next to a power pin (Can't remember which one). Assuming the rails are acting as 2nF capacitor and my PIC is driving the shift register at 4Mhz would this mean the "resistance" between the output pin and the power pin to be 0.02Ohms?
Would this be why it is pulling so much current? I've checked for short circuits and found nothing.
(Xc = 1/(2*PI*F*C))
(0.02 = 1/(2*3.141*4000000*0.000002))


Futz im siding with you here. Even if it was a "VHF radio" circuit it would not matter as the question was not on that part of the circuit it was on the power/osc side. :D
 
danielsmusic look at some of the neat things you can produce. I made this like 20 seconds each. Sorry if pictures arent the best. Im using a old 1.3MP webcam. I dont think that the header will add too much resistance since its way thinker than a normal trace anyway.
 

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danielsmusic look at some of the neat things you can produce.
Hey Atom. I have a Digikey number for trimpots that fit the breadboard perfectly. They're accurate and very compact and pretty blue too. :D I'll post it after work tonight.

The one at the upper right:
**broken link removed**

**broken link removed**
 
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GREAT! thanks i always having issue finding cool parts like that.

Nice to see site is up again. I always use your site as a reference point. :D

Nice new organization (categories)
 
GREAT! thanks i always having issue finding cool parts like that.
The 10K ones I have are CT6EP103-ND. They have a full range of values though. Just search for CT6EP and you'll get the list.

The very breadboardable SPDT slide switches that I use are EG1903-ND. Very handy to have some of these.
**broken link removed**
 
Hey futz! Could you tell me the ascii code for the degree character? The little circle before the C in degree Celsius, as seen on the picture of your LCD. I was trying to find out yesterday, but got all sort of strange symbols on my LCD.
 
Hey futz! Could you tell me the ascii code for the degree character? The little circle before the C in degree Celsius, as seen on the picture of your LCD. I was trying to find out yesterday, but got all sort of strange symbols on my LCD.

hi,
According to my data its 0xDF , [DFh] for the degree, its actually a small upper square.
 
hi,
According to my data its 0xDF , [DFh] for the degree, its actually a small upper square.

Thanks, Eric! That made the trick for my LCD. According to the extended ascii table, **broken link removed** , 0xDF is a "upper half block". 0xF8 is supposed to be the degree sign, but shows something strange on the LCD.
 
Thanks, Eric! That made the trick for my LCD. According to the extended ascii table, **broken link removed** , 0xDF is a "upper half block". 0xF8 is supposed to be the degree sign, but shows something strange on the LCD.

hi,
This image is the HD44780 character dot/bit pattern.
 

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the extended ASCII charecters doesn't work in swordfish?
not that?

I saw the only basic ASCII chars are accepted in swordfish LCD module..

but did somebody what is the bit pattern like the followin::

// initialise bit patterns...

// programmable characters are available that use codes $00 to $07.

// Create the bit patterns that make up the bars in the LCD's CGRAM.

// The vertical bars are made up of 8 identical bit patterns

const CGRAM(32) as byte = ($00,$00,$00,$00,$00,$00,$00,$00, // base bar

$10,$10,$10,$10,$10,$10,$10,$00, // 8 x %10000 = |

$14,$14,$14,$14,$14,$14,$14,$00, // 8 x %10100 = ||

$15,$15,$15,$15,$15,$15,$15,$00) // 8 x %10101 = |||


copied from swordfish LCD tutorial
 
I have the same problem with my breadboard. I've programmed the knight rider circuit on PIC16F877. The program works perfectly on a PIC developement board but when i tried to run the program using a breadboard it takes too much current and the PIC is beginning to warm up as well as the 7805 although LEDs are not lighting(the PIC is in good condition although it warmed up. I checked it using the PIC developement board). I think it has something to do with the MCLR pin(giving 5 volts).
 
well once i was facing similar problems i made the circuit four times but same result, but when i shifted the circuit to some other place on the board the problem was solved, in fact the rails were shorted within the bread board.
 
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