My future megadrum module.

[dmitri]

Just a quick reply to a question

btw, I had a question about the programing cables...
Wouldn't it be possible to program the atmega32 and the microcontroller of synthex's True usb board with the same cable ? (say a serial one)

No. At least not at the present time. There might be, but having these two programming cables made as simple as they are I don't want to spend more time searching for a way to make it even simpler.

Keep us posted!

[Lakedaemon]

today I soldered a few more things...
Here is a pic of my unfinished (32+32 inputs) megadrum all in one board...(I'm lacking some parts and I still have work to do)

HPIM0822.JPG

I'm stuck because there is something that I don't understand with the programming cable of the synthex true usb\midi board :

On the diagramm of the synthex programming cable and on the diagram of the synthex true usb board, the pins of the icsp.1 don't coincidate :
on one side, there is
2:VCC,
3:ground,
1:MCLR\VPP\RE3,
4:RB7\KBI3\RE3,
5:RB6\KBI2\PGC,
6:RB5\KB1\PGM

on the other side :
pin 1 and pin2 aren't connected
pin 4 is connected twice
the other pins are connected....

does it mean that we don't have to connect Vcc and MCLR\VPP\RE3 ?

Is it ok to connect the groundbut not vcc ?

[Synthex]

it looks nice.

All is right with the programming cable.
You must supply the PIC with the USB.

http://home.vrweb.de/~lotharstolz/stolz.de.be/lvpc/index.html

[Lakedaemon]

Thanks for the answer..I understand now....

Yet, because I don't have any serial port and I was planning to use an usb to serial cable, I'm a bit concerned about this :
Note that this circuit might not work on non-legacy serial ports! Only voltage levels of +0V and +5V are sent back to PC instead of -10V and +10V. This works well on my desktop-PCs having a serial high-low trigger voltage of about +2V. But my notebook connecting by an USB-serial-adapter don't cooperate with this circuit...



One other question that I had is I don't understand how the X pins of the multiplexers units are connected to the analogue connector :
I was expecting each X pin to be connected to 1 ADC pin of the atmega 32,
but on dmitri Analogue board diagramms....it looks like the upper X pin is connected to J2, J4 and J6 at the same time,
when the lower X pin is connected to J3, J5 and J7
What is even more confusing is that dmitri says you need 2 of those boards...
I'm at a loss to understand how to connect those X pins...

(I wish it were as simple as the A, B and C pins).....

[Lakedaemon]

on a side note, this sentence
"All the PIC's I/O-pins are protected against electric discharge by internal diodes to Vss and Vdd (see datasheet!). With a resistor limiting pin current, all voltages will get clamped between 0V and 5V."
makes me wonder if all those Bat85 diods were necessary (IF the atmega32 has this feature...)

[Synthex]

One other question that I had is I don't understand how the X pins of the multiplexers units are connected to the analogue connector :
I was expecting each X pin to be connected to 1 ADC pin of the atmega 32,
but on dmitri Analogue board diagramms....it looks like the upper X pin is connected to J2, J4 and J6 at the same time,
when the lower X pin is connected to J3, J5 and J7
What is even more confusing is that dmitri says you need 2 of those boards...
I'm at a loss to understand how to connect those X pins...
(I wish it were as simple as the A, B and C pins).....

Look at my all in one PCB to understand how to connect those pins.

[Synthex]

on a side note, this sentence
"All the PIC's I/O-pins are protected against electric discharge by internal diodes to Vss and Vdd (see datasheet!). With a resistor limiting pin current, all voltages will get clamped between 0V and 5V."
makes me wonder if all those Bat85 diods were necessary (IF the atmega32 has this feature...)

4051 must be protected.

[Lakedaemon]

Yesterday, I finished my all in one Digital+Analogue+Usb Card.

The whole experience took me like 4 or five 5 days
The difficult part being decide how to put the parts on the strip board,
and connect them....sometimes

I understand now why making pcb is much more clean and quick.
It's worth investing a few 100$ in stuff to make pcbs as it saves you days of design and work..

So here are my pictures :

back.jpg

front.JPG

I had to make a 1k resistor from three 330 resistors
And one 4.7k resistor from two 10k and one 6.2 k resistor

I still have to make the cables too and to program the ics...
This is going to be tough as I don't have a serial port nor a parallel one..
It'll have to work with usb and usb2parallel or usb2serial adaptators

[Lakedaemon]

Today..I completed 3 connectors :

The programming cable for the Pic 16F2550
The usb cable

I tried programming the pic 16F2550 but It failed (I'm using a usb to serial cable as I don't have a serial port on my computer)
(my usb to serial cable was recognized as port com8 by windows and I had to use winapi in winpic to programm the pic 16F2550)

I then completed the lcd cable and I connected it.
Yet....the lcd screen stays black....
Is it normal ?

I then tried to measure some voltages. Ground and VCC look like there are allright in my circuits, so I didn't mess my usb cable.
Yet...There is 4.9v on pins 2, 3 and 4 of the lcd screen.

This stays the same if I only connect ground and VCC to the lcd screen....

It feels really strange as I have connected a pot and the voltages don't change on pin 2, 3 and 4 of the LCD when I turn the pot's button....

Weird....
Is there something wrong ?

Tomorrow, I'll try to revive an old comp that has been lying in a corner for 2 years and I'll try to programm the pic16F2550 through a regular serial port...

[dmitri]

I tried programming the pic 16F2550 but It failed (I'm using a usb to serial cable as I don't have a serial port on my computer)
(my usb to serial cable was recognized as port com8 by windows and I had to use winapi in winpic to programm the pic 16F2550)

Programming with usb2serial adapter should in theory work since PIC18F2550 is programmed using LVP mode (low voltage).

I then completed the lcd cable and I connected it.
Yet....the lcd screen stays black....
Is it normal ?

depends on the voltage on the pin 3.

I then tried to measure some voltages. Ground and VCC look like there are allright in my circuits, so I didn't mess my usb cable.
Yet...There is 4.9v on pins 2, 3 and 4 of the lcd screen.

This stays the same if I only connect ground and VCC to the lcd screen....

It feels really strange as I have connected a pot and the voltages don't change on pin 2, 3 and 4 of the LCD when I turn the pot's button....

Weird....
Is there something wrong ?

There is definitely something wrong. You should be able to set voltage between 0 and +5 on pin 3 while turning the pot.

Tomorrow, I'll try to revive an old comp that has been lying in a corner for 2 years and I'll try to programm the pic16F2550 through a regular serial port...

I presume you're talking about PIC18F2550, aren't you?:)