Menu buttons etc connections

[Hermes]

Hello

First of all congradulations for this excellent project!! :D

I am in the process of building a MidiBox64 - using the old PIC16F877 (unfortunately it is impossible to find the PICF18452 in Greece for the time being). Since I am relatively new to both this project and electronics, I have some questions, which apparently have to do with basic matters, but to which I haven' t yet found an answer, neither in www.ucapps.de nor in this forum.

1) Can I assign the LCD menu functions to any 4 buttons I want, or must I choose these 4 buttons while I will be making the connections in the DIN module? In other words, are there any special connection points for the 4 menu buttons in the pcb, or can I decide which buttons will be used for the menu functions and program them after I build the MB64? ???

2) Can I use a on/off switch to the place of a pot? Can I use the switch to the place of a push-button?

3) I have not been able to find the 6N138 Optocoupler for the core module. Is there any suggested replacement for it? (I have found the 6N139 Opto.)

4) I want to place a fuse between the power supply input and the pcb. Which type of fuse should I use?

5) I am using the old pcb of greg macmillan' s (It is very convenient to have to make only one pcb). Is there anything I should note, apart from the instructions contained in the *.zip file?  

I hope you find some time to answer to these questions

Thanks in adnance

Greetings from Athens, Greece

Dimitris

[Ian_Hurlock]

I'll try answer some of these for you ;)

I think, from memory, the menu buttons are the first din connections ie 0,1,2,3.

I think the menu buttons are fixed unless you want to change the code.

Yes you can use a switch ( i did this )

You need to pull the input high or low through a 10k resistor as you do with buttons on the din.

If you consider a pot when it is up the resistance is below and vice versa. This is what you would do with a switch and 10k resistor. Basically you would end up sending 0 and 127 values. It works fine.

The 139 is ok for the opto.

The fuse would be dependent on how many pots etc you use.

You should be ok without. I don't think many have blown their pic's. I have built many now and real messy one's and they all live.

I can not comment on Greg's pcb as I made the standard core pcb from the site as it is now. I don't know who drew that one.

Hope this helps out and that i got it right ;)

Some clever bugger will let us know if I did not :o

Regards

Ian

BTW  check microchip.com for a free sample 18f452 ;)

[LO]

0.5A fuse is good but anything up to 1A should be enough protection

but get a few cause if you are like me youll blow a few while fault finding

[Hermes]

Thanks Ian & LO

This is great help :)  (I hope I manage to build a metal panel cheeply...)

I forgot to ask if anyone knows if there is any way to reverse the polarity of the faders so as to simulate the Hammond Organ drawbars for use with i.e. Native Instruments B4 (It would be ideal to have this as an option in the sofware). Anyway I will post this in a separate topic.

[Ian_Hurlock]

Just mount your faders upside down ...same difference

Ian

[uclaros]

Hi hermes,

you can order the pic18f452 as a free sample at sample.microchip.com

It is the best (and cheapest) way to find it in greece!

(I'm in greece too!)

[Hermes]

Thanks to  Ian and uclaros!

At the moment I have 3 PIC18F452 (got them for free from Microchip as samples - they were also delivered to me for free).

SO ... I ll go for MIOS.

Thanks again to everyone