Programmer i am building.

[Marks256]

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I have decided to build this programmer for my pic 16f182. I have everything for it (or should be able to find what i don't have). The only thing i think i will have a problem finding is the 7407 HEX BUFF/DRIVER OC. Is there any circuit that i can use to substitute for it? I have an old IBM PC XT that has quite a few ICs on it, which may have the 7407, but just in case it doesn't; are there any substitutions?

Thanks!

 

[Nigel Goodwin]

Use an NPN transistor and two resistors for each open collector buffer you need, no need to use an IC.

 

[Marks256]

How would i do that? I just did a quick google, but didn't quite find what you meant...

 

[Nigel Goodwin]

How would i do that? I just did a quick google, but didn't quite find what you meant...

Emitter to ground, one resistor from base to emitter, second resistor from input to base, and the collector is the output. It makes a logic level inverting open collector buffer - just what you need!.

 

[Marks256]

Thanks. I have attached what i understood. What would the resistor values be? I am guessing R1 would be very low? And R2 10k? Just a guess...

Thanks for the quick response!

 

[Nigel Goodwin]

Thanks. I have attached what i understood. What would the resistor values be? I am guessing R1 would be very low? And R2 10k? Just a guess...

Thanks for the quick response!

10K for both would be fine, R1 doesn't want to be very low (and mustn't be!).

 

[Marks256]

10K for both would be fine, R1 doesn't want to be very low (and mustn't be!).

10K for both? Great, i am out of 10K resistors... Oh well, i will just desolder a few... Was my schematic correct?





EDIT:

Also, would it be fine if i just left out the entire power supply circuit? I have an old external CD-ROM psu, wich give off a regulated 12 and 5 volts, so it would save some time...

 

[mneary]

10K is a good value, but you can probably use anything from 10k to 47k. Should be similar values, to get a reasonable switching threshold.

 

[Nigel Goodwin]

10K for both? Great, i am out of 10K resistors... Oh well, i will just desolder a few... Was my schematic correct?





EDIT:

Also, would it be fine if i just left out the entire power supply circuit? I have an old external CD-ROM psu, wich give off a regulated 12 and 5 volts, so it would save some time...

You really need 13V rather than 12V, and you don't need much current at all.

 

[Marks256]

You really need 13V rather than 12V, and you don't need much current at all

So is that a yes or no?

 

[Nigel Goodwin]

So is that a yes or no?

It's a NO!.

 

[Hero999]

Look at the programmer I built you can copy the power supply I used!

 

[blueroomelectronics]

Since you want just an elementary programmer try a simple LVP one.

**broken link removed**
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[v1r05]

better go with JDM type i havent had any problem with it whatsoever check this out **broken link removed**

very nice design and works perfectly and you can use good software like icproc winproc and winproc800(for 18f's i had problems with winproc)

JUST MAKE SURE YOU GOT +,- 7.5V AT TxD, DTR, and RTS

 

[Gayan Soyza]

better go with JDM type i havent had any problem with it whatsoever check this out **broken link removed**

very nice design and works perfectly and you can use good software like icproc winproc and winproc800(for 18f's i had problems with winproc)

JUST MAKE SURE YOU GOT +,- 7.5V AT TxD, DTR, and RTS

I have the same programmer.Works good.But did you try programming PIC 12F629? I got some problems when programming this PIC with INTOSC feature.
Because it cannot control VDD, "VPP before VDD" is inapplicable.So I had to adjust the circuit.

 

[Souper man]

I looked at this, and I think this is what I want/need/wish to build. Any more help would be sweet!

I Looked at the schematic, and I dont know where the chip goes. Do i put it where U4 is? Some help please

 

[v1r05]

yes you put it there, and lets you got a 877a or any other pic not 18 pin what are you gona do ? you can insert it in there right? you have to stick 5 wires in the socket to get the programming signals and givem to the PIC which is bad you dont want to do that

if you dont like the JDM type go for other david tiat which got a zif socket on it makes your life much easier. go for something good and worth building that you could use for lots of pics until the copper tracks oxidize.

good luck

 

[Souper man]

Sry I am using a 16f628

 

[Souper man]

does he use a 16f84 as an exampleon the schemmy?

 

[3v0]

After building one of these simple programmers the first thing you should to do is build an ICD2 clone. After that the programmer will sit on the shelf because the ICD2 has debug(run control etc) and Microchip keeps the software up to date.

The ICD2 can be built for not a lot of money. Mostly a 16F877A, crystal, MAX232, 2 LEDs, 4 transistors and a handful of caps and resistors.

If you want to be stingy you can skip the power supply and power it from the target.