Programming the pic16F84A

I doubt it's true, but I'd suggest a kit, from eBay perhaps.

You really should use an external power source. You can use a cheap DC adaptor with a regulator. You will need both 13 and 5V's so you'll probably want something like a 15-17V DC adaptor with a 13V and 5V regulator. Once you got this you'll also need a tristate ic so you can control them and a few transistors to interface the power with the pc. There are plenty of schematics out there for it. The one your looking at is pretty basic and is crap.

something like this should work... its very similar to what I did and I didn't have a huge problem with it. (although I used a bench supply so I didn't need the regulators). If your not using Winpic then you should pic that up as its probably the best to use. It also has many default settings for popular programmers. You gotta make sure that the controls from the pc match what the pic see's. i.e., when the software turns on the main voltage it actually comes on and doesn't go off or something like that... also that.

in win pic it lets you test the controls to so you can figure it all out quite easily.

Theres tons of resources on the net and spending a little time with google might make it much easier.

Jon

Jon Slaughter a =E9crit :

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I finally got that crappy circuit to work with the power supply at 5 volt. Eventually I would like to program bigger chip, I was inititially thinking of doing this circuit:

ken

Jon Slaughter a écrit :

I finally got that crappy circuit to work with the power supply at 5 volt. Eventually I would like to program bigger chip, I was inititially thinking of doing this circuit:

Yeah, but its still better to use an external power supply since the standard for the pc ports is not all that standard. It may or may not work in some situations. Its very easy to use an external power supply so one might as well do it if they want the programmer to be more robust.

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Ken,

That COM-port powered programmers tend to work well when 1488 drivers are used in the PC. The output voltages of that drivers are close to +/-12V when powered by appropriate power supplies. These days the drivers are often build in a larger IC and have lower output voltages although well within the RS232 specs. Especially notebooks may use MAX232-like solutions that do about +/-9V. Good enough for serial communications but too low for programming PICs.

So to stay on the safe side you'd use an external power supply. Examples:

Another programmer can be found:

Which are only two examples among many, many others.

petrus bitbyter

Hello :-)

Definitely buy one off of eBay. It removes uncertainly from the equation (most of the time..) Try to go for a PicStart+ or ICD2 clone rather than one of these 'kits'. It was the best thing I ever did and I'd used a DIY programmer for about a year.

The 16f628 would perhaps be better to start with too.

Before you proceed too far with the 16F84A take a read of my PIC

while getting started with a 16F84A is probably OK, you'll probably find that you'll quickly run into some real limitation before too long.

Which designs are those.

That's not good at all. Most serial ports generate at least 0-5V.

True.

Answer #1: Don't use the serial port.

Answer #2: supplement the voltage.

But serial ports are a crap shoot. Parallel ports tend to have more stable specifications. Take a look at my Trivial High Voltage Programmer

as a sample. Note that it requires an external 13V power supply.

With newer chips such as the 16F88 you can also program with low voltage which obviates the need of a high voltage supply. Also many newper parts only requires a Vpp of +3.5V above Vdd. So often you can program using a 9V battery as the high voltage source.

They could be. What are they? Also what software are you using?

BAJ

yes actually I just saw that the PIC16F88 was a much better choice then the 16F84A I'm going to look in to ebay if my circuit do not work. But for now I want to try to build my own. I just order a plain board (15$) and I will install myself the component, that should be wiser then etching the board myself. I have a pic progammer from microchip I can use to compare that from school so I,ll see if its the board or me (or the program ) my problem. Also one more thing.

On the web site they say to use a 13-18V 150mA transformer adapter. I called the electronic stores nearby and they only have a minimum of

ken

techie_alison a =E9crit :

I called the electronic stores nearby and they only have a minimum of

Sure. A power outlet can deliver 2500 watts. You can plug a 15 W lamp in OK. Same principle.

Homer J Simpson a =E9crit :

OK.

oK THEN

I just thought that the circuit was design to support 150mA. By putting

ken

I just thought that the circuit was design to support 150mA. By putting

Nope. Excess voltage kills things.