[PIC] PIC16X84A JDM Burner issue

Hi Every body
I'm newbie to pic programming,and i have PIC16f84A chip and tried to make a JDM burner circuit as the attached one and it takes the power from the serial port so 'it doesn't need an external power source

but it doesn't work,
I'm using winpic800 ver 3.6 as burning software
when i lunch it and choose my pic and open the hex file to be burned and press "programm all", I got the message "failed to install--> W800io.stys" and nothing happen
even when i press "read all" I got the same message

I've used another burner SW called "PICPGM" ver 1.7.8.0,when i lunch it and press "auto detect" it display a message "No PIC Connected"
and when h'm choosing my PIC mdel manually and press "verify button".

so pls help is there any error in the circuit diagram i noticed that osc1,osc2 pins is floated ,or may be it need a modification to use external power source
,if u have any working burner circuit for the PIC 16F84A i'll be appreciate

4EverYoungs.71 said:

it takes the power from the serial port so 'it doesn't need an external power source

Click to expand...

Are you using a native serial port from computer, or some kind of USB/Serial converter ?



+++

Hi,

JDMs can be problematic for some , work fine for others.

Search this forum with 'jdm' and you will find masses of good info and circuits.

If you have a parallel port (?) you will probably find a parallel programmer more stable.

thanks to wp100 and with respect to andre_teprom question,
I'm using native serial port of my pc

Measure the Vpp by adding two diodes in series with the 13v zener (to get extra voltage) and let me know the EXACT voltage

Measure the Vpp by adding two diodes in series with the 13v zener (to get extra voltage) and let me know the EXACT voltage

Click to expand...

please what's the pin number of Vpp as the data sheet of PIC16f84A tell,there's two voltages pins Vdd Pin14(+ve supply) and Vss Pin5(Ground)
any way I've measured the some voltages(without adding any thing to the circuit) with respect to Pin5(Gnd) of the pic

Vdd(Pin 14)(+V)=3.45V
MCLR(Pin 4)=3.94V (it's the voltage on the 13V zener )

but i noticed that the Gnd pin of the serial port (pin 5) is connected to (Pin 14) of the PIC which is the postive supply source for the pic and it make me confused

Vpp is measured between pins 4 and 5.
If pin 4 is 4v, that's your problem. Are you using a DVM?

colin55 said:

Vpp is measured between pins 4 and 5.
If pin 4 is 4v, that's your problem. Are you using a DVM?

Click to expand...

based on your definition for vpp then it's 3.94 volt,
pls do u mean by DVM digital volt meter,
if so then my answer is yes I'm using DVM,
pls what's the default value for Vpp ?

The Vpp voltage must be higher than 13v. Some chips will not open (will not start programming) until the voltage reaches 13.6v and so the programmer I designed on my website produces 14v to open ALL chips. The voltage can go higher than 15v without damaging the chip as this pin does not have protection diodes and it has an internal resistor to prevent damage to the components on the pin.
I have a modification on my website to fix your problem but we must get a voltage above 10v before we can advance any further.
I would prefer you use a sensitive Analogue meter because the voltage on the pin is fluctuating and a Digital Multimeter is not accurate at measuring this type of voltage.
These are all things you will learn when you visit my site as electronics is much more complex than you think.

(colin55) The Vpp voltage must be higher than 13v

Click to expand...

colin55 do u have an idea to rise up the voltage from 3.4v to 10v,
i thinking of cancelling the power supplier from the serial port which go to pin 4,5 and 14 and making external power.
with respect to ur website would u like sharing the link to it