What are the programming PINS for 18F4550 PIC

[mutthunaveen]

Hi board

I have purchased a USB compatible PIC18F4550. last weekend. I used JDM programmer + WINPIC to program the chip (16F877A my previous PIC). When I connect in the same 40pin socket and tried to write the program. But the WINPIC says programming failed.

Now I am confused whether the PIC (18F4550) is damaged piece when I bought it. Or my programming pins are not correct.

Can anyone plz tell me what are the programming pins for 18F4550 (is this same as 16F877A) or different.

Plz help me (I don't want to waste money by buying a new chip due to my knowledge lag).

[Ttelmah]

If you go to the Microchip site, for the chip, in the page offering the data sheets, you will find the 'programming specification' sheets.
The pins for standard programming (not LVP), are the same.

Now, first, have you used your JDM, with the actual PC you are trying?. The JDM style programmers rely on a serial port that delivers something over 8.5v, to supply the Vpp voltage. A lot of newer PC's (and especially laptops), don't do this, and require you to use an external supply.
The Vpp required by the 4550, is a fraction higher than on the 677. The 677, requires Vdd+3.5v, while the 4550, requires Vdd+4v (so 9v, with a 5v Vdd).

Best Wishes

[mutthunaveen]

The JDM programmer is not actually JDM it is bought from (they said this is a JDM programmer) the market. This programmer utilizes external power supply (230V AC) and in my PC I connect this to serial port.

When I code the 16F877A it says success
immediately after I change the program to and compile then load into 18F4550 (the programming failed)......

Thanks, for your suggestion and reply. I will check with the Microchip site. Ttelmah thank you

[Ttelmah]

I don't think the WinPic software was ever actually 'officially' tested with the 4550. The author reports that it was tested with a 2550 though. It may just be something silly like the wrong device ID, so the code doesn't recognise the device....

Best Wishes