www.megadrum.info

Hey guys, i would like to start off this thread by thanking Dmitri and Synthex for their amazing contributions to this project, and everyone else that has posted the progress of their builds.

This is the first time i have ever made my own pcb and first time ever taking on a project from scratch like this, i enjoy it alot (but im cursing it at the same time too )

I used Synthex's all in one PCB design 2.5 located on this thread: (thread includes list of parts that i used)
http://www.megadrum.info/forums/viewtopic.php?f=3&t=198

To catch up to speed to where I'm at in my build here's a picture:


I know i'm missing the midi IC, however i'm assuming i dont need it if intend on using USB, the IC is on backorder from Mouser. I'm expecting it to ship about the 27th

The LED is missing from the board because i orginally put it in backwards, and when trying to remove it i started to remove some trace, so i follow the trace back to a terminal and soldered 2 ide wires (off to the left coming from under the pcb in the picture) so that i can have the LED off the board.

At first i had trouble programming the PIC18F2550, but after browsing around someone suggested using an external powersupply because some motherboards dont have enough juice over usb, which was exactly my case. I hooked it up to AC USB adaptered, and the ISCP for the PIC and the program automatically recognized it, and said the program was successful. However the USB is not recognized, and i cant get either xp or vista to even do anything when i plug in the usb.

As for the Atmega, i'm using an Atmega644, with a 20 MHz crystal, and programed the 32 input version using the ISCP cable for the Atmega. Again, the program said successful. I can even verify that it works by hooking a piezo up to the kick channel, and giving it a few taps, and the LED lights verifying the signal.

LCD is a different story. I think i get better results hooking up the backwards (which i stupidly did in the first place)...
When hooked up correctly i get the top row all solid boxes, and never changes (contrast can fade, but input does nothing). When it is hooked up backwards the top row is still solid boxes, but they alittle faded (contrast does very little to change that) , however with input the the whole row flickers either getting dimmer or a quick flash. This is from either input from the controls or the piezo.

So right now i'm having two problems:

USB - Windows does not detect anything when plugged in, no little bubble on the bottom right, nothing...

LCD - The screen does not display anything that would resemble the MegaDrum, it reacts only when plugged in backwards:

LCD TERMINAL:
Correct:

Code: Select all

16 15
14 13
12 11
10  9
8  7
6   5 
4   3
2   1

Mistake:

Code: Select all

1  2
3  4
5  6
7  8
9  10
11 12
13 14
15 16

I really love working on this thing, but i've checked all the traces and connections to the best of my knowledge, and now am in a jam, appreciate any bit of help, Thanks.

bobnickelson wrote:So right now i'm having two problems:

USB - Windows does not detect anything when plugged in, no little bubble on the bottom right, nothing...

No "USB Audio" in the Device Manager?
Take Atmega out of the socket. Still no "USB Audio" in the Device Manager?

LCD - The screen does not display anything that would resemble the MegaDrum, it reacts only when plugged in backwards:

By putting the LCD backwards it is very likely that you damaged it.

The Mouser.com shopping list doesn't include anything to connect to the single-row headers as Mouser apparently doesn't carry such a product. So what did you use on the end of your wires/cables connecting to the ICSP and keyboard headers?

dmitri wrote:No "USB Audio" in the Device Manager?
Take Atmega out of the socket. Still no "USB Audio" in the Device Manager?

i just gave that a go and it still doesnt do anything

By putting the LCD backwards it is very likely that you damaged it.

Damn i guess thats just what happens when i rush things...

gastric wrote:The Mouser.com shopping list doesn't include anything to connect to the single-row headers as Mouser apparently doesn't carry such a product. So what did you use on the end of your wires/cables connecting to the ICSP and keyboard headers?

I used a few random things, for the USB ICSP i used the a 40 pin ide, and used the first 6 pins for the adapter, for the atmega i used a 6 pin connector and have the last pin not connected, and for the controls i used a 2x5 header from a dell computer.

Are there any components other then diodes that matter which way they are placed on the board? I'm just wondering if its possible that the crystal was placed backwards, if that might affect whether it would work.

bobnickelson wrote:

dmitri wrote:No "USB Audio" in the Device Manager?
Take Atmega out of the socket. Still no "USB Audio" in the Device Manager?

i just gave that a go and it still doesnt do anything

Program PIC18F2550 again.
Still no go? (again, without Atmega in the socket)

I still got nothing, the usb powers the whole board fine, and the data lines go directly to the chip, i test the line from the actualy usb connecter, and all four lines have no breaks.

bobnickelson wrote:I still got nothing, the usb powers the whole board fine, and the data lines go directly to the chip, i test the line from the actualy usb connecter, and all four lines have no breaks.

Have you programmed with verification?
Verification reported that it had been programmed ok?
Have you tried another usb cable?
Have you tried another usb port?
Is the crystal exactly 12MHz?
Is there +3.3V on a pin 14 of PIC18F2550?
Are you sure you didn't mix up D+ and D- of the USB connector?

dmitri wrote:Have you programmed with verification?
Verification reported that it had been programmed ok?

I use PICPgm Programmer, I had to use an external power supply to program it when the Atmega was plugged in, but when i tried with no Atmega it works fine just running of the usb power. After the PICpgm is done programing it says successful, it verfies that it is correct.

Have you tried another usb cable?

I have checked the continuity with my multimeter, and the usb cable is fine.

Have you tried another usb port?

Yes

Is the crystal exactly 12MHz?

Its printed right on the side of it yes.

Is there +3.3V on a pin 14 of PIC18F2550?

Only when hooked up to my external power supply the multi meter reads 2.8 volts, otherwise on the pc (and my laptop) there is 0.

Are you sure you didn't mix up D+ and D- of the USB connector?

Checked the continuity with the multi meter, from each point ground, +,-, and 5v from the solder points from the board directly to the male usb end, and the wiring for the USB contacts are correct.

bobnickelson wrote:

Have you tried another usb cable?

I have checked the continuity with my multimeter, and the usb cable is fine.

Still, have you tried another cable?

Is there +3.3V on a pin 14 of PIC18F2550?

Only when hooked up to my external power supply the multi meter reads 2.8 volts, otherwise on the pc (and my laptop) there is 0.

Do you read +5 on a pin 20 of PIC18F2550? There must be +3.3V on the pin 14. Otherwise it won't work properly.