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.asm help for keyboard controller


d2k
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Hey...

So, I started a conversion on an old commadore 5octave keyboard i bought for peanuts to use as a bog standard midi controller kb with velocity sensitvity based on the project on this site: http://homepage.ntlworld.com/derek.johnson/

I've sucessfully adapted the key's to form switches on the top and bottom rails and have breadboarded the pcbs which were quick to do. Now i need to burn the PIC (uses the 16F877 as in mbhp), the .zip file for the project (http://homepage.ntlworld.com/derek.johnson/velokbd.zip) contains an .asm file which i kinda thought I could load in a new project in mplab, build a new hex file and then burn that to the pic via icprog. Is that correct? I get errors msgs when it builds the hex file (even tho it does it) and then when i load the hex file in icprog i get more msg about bytes being swapped or summin :/ The Pic did burn tho...

I was thinking however - could this code in the asm file be implemented in MIOS sumway? the IC's it uses to decode the switches before sending to the PIC are some 74HC138s - could I make up a special din module that uses these?

Best

Dan

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Hi Dan,

these are warning messages. "BUILD SUCCEEDED" means that the file has been assembled successfully.

Message[302] can be disabled with following line in the assembler code:

        ERRORLEVEL      -302
The IC-Prog message
"The file does not contain any configuration information!"

can be ignored, just disable this check somewhere in the options menu

Best Regards, Thorsten.

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Thanks T...that has put my mind at rest now :)

D'ya think a MIOS port of this app is doable? i'm assuming I could include more features - or perhaps it'd be best to use this as is and use a sep core module for any further processing...

Cheers

Dan

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  • 4 weeks later...

okay, so this project seems a bit of a no-no...:/

I made up a pcb and converted the keys, but i'm gettin no midi out of it whatsoever :(. I'm sure the problem is in the asm file and the way i've gone about gettin it burnt to the PIC. I've tried emailing the fella but the email link on the site is returning msgs :/ - looks like he gave up on it n all then....

So, i'm left with a nice commadore 5 octave keyboard with the key's converted so they function as switches which hit 1 of 2 bus bars when struck. Same principle as in this image:

keymech2.GIF

These then are connected to this (think din/dout modules):

keydec.GIF

My thinking now is, can MIOS step in and rescue this project? It'd be a nice1, and a good project for the new MB portal...:)

Best...

Dan

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  • 2 weeks later...

okay, good news...:)

So, I have it like each key acting as a switch on 2 buss bars (NO and NC). With nothing pressed the keys all lie on the top bar and connect to the bottom bar when struck...

How would the key contacts be treated in mios compared to the NO/NC contacts?

I guess we could even have velocity sensitivity by using some kinda counter ye?

Cheers

Dan

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  • 4 months later...

Hi...

So getting back to this...how does this sound:

61 Din inputs (for the keys)

2 Dout outputs for the top and bottom rails (NO/NC)

Start state: Top DOUT = 0, Bottom = 1. Then: Clock in all DINs. Which ever are set to 0 are sitting at the top. Next: Set top =1, bottom = 0. Then: Clock in all the DINS. Which ever are set to 0 are fully pressed. Any key that read 1 on both passes was moving at the time. We time clock up a timer for each moving key - and repeat the process...we can then see which keys are pressed, and how long then took to get from top to bottom...

making sense?

Best

Dan

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No - but I would use serial shift registers due to the re-usability.

But just wait for 2-3 weeks... I'm planning to provide a (tested) keyscan algorithm for a 5 octave keyboard. Its a MIOS based replacement for an old Polykobol synth of a friend.

It will just only require one 74HC595, one 74HC165 and 60 diodes

It won't support velocity (since this keyboard only has single contacts), but this is something which you could add and test with your equipment. The velocity feature will require one additional 74HC165

Best Regards, Thorsten.

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Hey T...

But just wait for 2-3 weeks... I'm planning to provide a (tested) keyscan algorithm for a 5 octave keyboard. Its a MIOS based replacement for an old Polykobol synth of a friend.  

It will just only require one 74HC595, one 74HC165 and 60 diodes

Intersting :D I'm in no rush for this one so will wait to peep ur methods neways :)

It won't support velocity (since this keyboard only has single contacts), but this is something which you could add and test with your equipment. The velocity feature will require one additional 74HC165

Cool! I'll def try the velocity version!

Cheers T!

Dan

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