LPT GND

[4electros]

I want to ask a question: Am i forced to ground all LPT pins(18-19-20...25) I have grounded only two pins(18-25) , could you answer me please!!

 

[Nigel Goodwin]

I want to ask a question: Am i forced to ground all LPT pins(18-19-20...25) I have grounded only two pins(18-25) , could you answer me please!!

You only need to use one of them, they are all the same (or they should be!).

 

[4electros]

You only need to use one of them, they are all the same (or they should be!).

Thanks a lot for this explaining!

Another question, i measured the alternating votlage(AC) it was about 19v
and also measured DC voltage at the output of bridge recitifer and it was about 23.7v, i think these these values are consulted depending on the law: Vdc=Veff*root(2), but i'm not sure....what's your opinion ?!

 

[checkmate]

As a general rule, it's good design practice to just ground them all, as everyone simply assumes that everyone else grounds them all. This way, anyone who is going to modify your design won't have to waste time figuring out why some pins are not grounded, and just in case the parallel port on the host side fails to ground all the pins.

 

[checkmate]

Another question, i measured the alternating votlage(AC) it was about 19v
and also measured DC voltage at the output of bridge recitifer and it was about 23.7v, i think these these values are consulted depending on the law: Vdc=Veff*root(2), but i'm not sure....what's your opinion ?!

AC voltages are normally given in rms values.
AC-DC conversion involves full-wave rectification, followed by a low-pass filter. Vac*root(2) gives you the peak value of sinusoidal AC. Depending on the quality of your low pass filter, the resulting DC voltage should be slightly lower than the peak sinusoidal voltage.

 

[4electros]

You only need to use one of them, they are all the same (or they should be!).

I've tested them the pins(18 to 25) are not the same!!

 

[GraveYard_Killer]

if you tried looking at www.beyondlogic.org, it says that pins 18 to 25 are ground (standard parallel port with 25 pins).

i checked my parallel port with multimeter, it seems that 18 to 25 ground pins are already connected. i agree with checkmate that its a good practice to have a robust grounding connection.

 

[eblc1388]

Link pins18-25 with a thin wire at the DB25 socket of the programmer(I'm assuming you're building a programmer). Very easy to do and avoids all problem with different cables. Cheap cable has only one core for ground connection and which pin it connects to is anyone's guess although good cable manufacturer would certainly links all the above pins but who knows.

 

[Elektor]

grounding

8 wires are only for avoiding cross talk in each data signal D0-D7.They are actually connected internally as well as to ground.

 

[4electros]

leds

The red led and green led next to each other in programmer p16pro40 didn't light that is they didn't work and other red led did work...
I haven't placed my pic in the circuit yet , might be that the reason or likely there's another reason?!

 

[4electros]

principle of circuit

could anyone explain to me about the general principle of p16pro40 programmer circuit?

 

[Nigel Goodwin]

Re: principle of circuit

could anyone explain to me about the general principle of p16pro40 programmer circuit?

It's VERY simple, just open collector buffers and switching transistors. If the LED's aren't lighting up, then you have something seriously wrong!.

 

[4electros]

Re: principle of circuit

If the LED's aren't lighting up, then you have something seriously wrong!.

something like what, could you give me an example?!

 

[Nigel Goodwin]

Re: principle of circuit

If the LED's aren't lighting up, then you have something seriously wrong!.

something like what, could you give me an example?!

Something like you've got it set to the wrong parallel port!, you can check using the hardware toggle buttons in WinPicProg and a simple meter to check the voltages.

 

[4electros]

Re: principle of circuit

If the LED's aren't lighting up, then you have something seriously wrong!.

something like what, could you give me an example?!

Something like you've got it set to the wrong parallel port!, you can check using the hardware toggle buttons in WinPicProg and a simple meter to check the voltages.

I tried the buttons located in hardware options but i really don't know what's happening , i didn't know what is the function of each button, so i became a little confused!!

I really need your advice , could you?

 

[Nigel Goodwin]

Re: principle of circuit

If the LED's aren't lighting up, then you have something seriously wrong!.

something like what, could you give me an example?!

Something like you've got it set to the wrong parallel port!, you can check using the hardware toggle buttons in WinPicProg and a simple meter to check the voltages.

I tried the buttons located in hardware options but i really don't know what's happening , i didn't know what is the function of each button, so i became a little confused!!

I really need your advice , could you?

All a parallel port PIC programmer does is 'wiggle' the output lines UP and DOWN, the hardware toggle buttons let you do this manually, so you can test the results with a voltmeter.

WinPicProg automatically detects the programmer on the port, so for a start, is it being detected? - the power to the programmer must be turned on for this to work.

Assuming it is, toggling Vdd should turn the Vdd LED ON and OFF, likewise toggling Vpp should switch the Vpp LED.

 

[eblc1388]

Hi 4electros,

Have you followed the schematic of P16PRO40 exactly? What is the part numbers of the 14-pin IC and PNP transistors you have use?

 

[4electros]

yes

Hi 4electros,

Have you followed the schematic of P16PRO40 exactly? What is the part numbers of the 14-pin IC and PNP transistors you have use?

I have followed the schematic of p16pro40 exactly :cry:

 

[eblc1388]

Re: yes

I have followed the schematic of p16pro40 exactly :cry:

Measure the voltages at the following test points A-H, without the parallel cable connected, no PIC in socket and just DC power to the circuit. Black lead of meter connects to 0V.

Post back the results.