My future megadrum module.

[Lakedaemon]

I see....well. I'll investigate further later....

It's either my cabling that is likely the cause....
Or the LCD that is broken....(bought it on ebay)
Or the pot that is broken (very unlikely).


Concerning the pic18F2550, I hope I'll be able to program it....

[Lakedaemon]

Today, I revived my oild comp that had been lying there for 3 years.
The old beast still works fine and it has 2 serial ports and 1 lpt port (hoorey).

Yet I couldn't program the 18F2550 with Winpic :
I tried with both com ports.....

1) I opened winpic....
2) I set Pic18F2550 in the device tab,
3) I selected the JDM2 programmer
3) I loaded Syntex Hex File
4) I pushed the code+data+programm button....

It reported programming errors.

When I tried to read the pic's memory.....it was blank (or filled with FF don't remember...)

I then went into winpic's Faq and read there that :


If you use the "JDM PIC-programmer 2" (the one where the PIC's ground is on a negative voltage), disconnect "RB4" which is pin 10 for the 16F628 and other 18-pin devices. This pin selects low-voltage-programming mode for some modern PICs, which causes conflicts with the JDM- and other programmers. The low-voltage programming algorithm is not implemented in WinPic anyway.
- If the problem occurrs with a dsPIC30Fxxxx or a PIC18Fxxxx, read this note on "PGD and PGC filtering" !

About PGD and PGC filtering: There was a note on the Microchip forum (by Olin Lathrop) about programming the dsPIC30F201(**), suggesting to put 22..47 pF on the PGD and PGC lines to ground near the target chip. In addition, put a 100 ohm resistor in series with the PGD line between target chip and the cap. The resistor and cap on the PGD line low pass filter the PGD signal when it is driven by the target chip. This reduces the high frequencies that can couple onto the PGC line. The cap on the PGC line makes it less suceptible to coupled noise.
(**) We later found out that this important note also applies to the PIC18Fxxxx family. A user of a Velleman PIC programmer reported success with a PIC18F4520 after adding 2 * 33 pF caps and a 100 Ohm series resistor.


Now, what does it mean for me ?

It seems strange because dmitri said that he had used winpic to program his 16F2550.
Or is there another software out there that'll work better for me ?

ok..waiting for help, I'm now going to check what's wrong with pin 3 of my lcd

[dmitri]

When you try to program PIC18F2550 do you provide it with the power from USB? You must power up PIC18F2550 externally when programming with my version of ICSP cable.

[Lakedaemon]

ok....the pots is working just fine.....and the wire was moving in pin 2 of the lcd...

So, I'll resolder the pins of the lcd....

Could you please tell me if the lcd is supposed to display something when ground and VCC are coinnected...
Or does the LCD need the atmega to be programmed and working to start to light and to display things ?

[dmitri]

Could you please tell me if the lcd is supposed to display something when ground and VCC are coinnected...
Or does the LCD need the atmega to be programmed and working to start to light and to display things ?

It should show black boxes in the top row and they should appear/disappear when you rotate the pot.