a tiny midi-processor

[avogra]

Hey everyone!

after half a year lurking around ucapps and the forum, i finally ordered a bare core from mike's and got into things :) I didn't believe that anything would work the first time. but - praise to great tutorials for a great platform! - voltages where correct, nothing smelled suspiciously when trying with the pic plugged in, and when looking carefully, i even noticed the stiffed in led flickering a little :) i wasn't prepared to be so happy about a led :)

when i arrived at my pc (200km away -.-) with already set-up toolchain, the next moment of excitement was waiting for me: will it talk to me??? and jepp, it did periodically :) uploading mios was just a hop. so its coding time for my first c-app!

what i'm after: main intention is a velocity converter to take care of the odd velocity-curve of my yamaha P80. next issue is teaching my floorboard to talk sysex. up to now, thats all i need. although a 3-port merger would be nice, and maybe some knobs n buttons to supplement or even replace the floorboard, and... hm i'm not even lightly scratching the possibilities of mios, d'oh!

but better get into things step-by-step, so back to the velocity converter, which really gave me headaches. it should be really simple, but as my even little C-skills are quite rusted, it took me 3 hours to figure out how to implement a basic translation-table. at least it works now :) lets see how i will cope with the sysex stuff :-P

so far, many many thanks to Thorsten and everyone else for the fun, that mbhp and mios have already given to me! awesome work!!

cu, Alex

[lylehaze]

Congrats on getting well started.

Since I usually do asm instead of C, I may be giving bad advice, but I was faced with a similar challenge in converting from linear to log and back again.

I eventually used Excel to calculate (and graph) the desired curve, then I abused it into writing the asm source code for me. It was a bit ugly up front, but I now have the easy means to alter the curve and re-generate the needed source code.

If that sounds interesting to you, you will find the spreadsheet in this zip file:

http://www.midibox.org/dokuwiki/lib/exe/fetch.php?media=pga:logcurve.zip

It makes a nice bridge from the easy office spreadsheet to the source code.

In any case, have fun!

LyleHaze

[nILS]

As I already said in the chat - welcome aboard! ;D

[TK.]

so far, many many thanks to Thorsten and everyone else for the fun, that mbhp and mios have already given to me! awesome work!!

I'm glad to read this :)

Best Regards, Thorsten.

[avogra]

Thanks for the welcome :)

@lylehaze: thnx for the hint. i did something similar in *cough* basic, that generates a file, ready for copy n paste.

right now, im somewhat stuck in ashaming (?) C-Basics :(

The velocity translation works perfect. What i did next, is a very basic sysex-parser. but i don't get it to compile. seems to have to do with my includes: the function sysex_parse() is in the file midi_process.c, functions are declared in midi_process.h . the .h-file is included in the main.c

when i also #include midi_process.c , it compiles fine.

Someone have a look? I stripped the code down to the basics and moved the function call into Init(void) for shortness, so don't be puzzeled, what's its purpose there :) also attached complete files in test.rar

Console output first:

CD: C:\Eigene Dateien\MIOS\test\
Current directory: C:\Eigene Dateien\MIOS\test
make
Process started >>>
rm -rf _output/*
rm -rf _output
rm -rf *.cod *.map *.lst
rm -rf *.hex
mkdir -p _output
sh C:\Programme\MIOS_base\bin/mios-gpasm -c -p p18f452 -I./src -I C:\Programme\MIOS_base/include/asm -I C:\Programme\MIOS_base/include/share -I C:\Programme\MIOS_base/modules/app_lcd/dummy -DDEBUG_MODE=0  -DSTACK_HEAD=0x37f -DSTACK_IRQ_HEAD=0x33f -I C:\Programme\MIOS_base/modules/mios_wrapper C:\Programme\MIOS_base/modules/mios_wrapper/mios_wrapper.asm  -o _output/mios_wrapper.o
sh C:\Programme\MIOS_base\bin/mios-gpasm -c -p p18f452 -I./src -I C:\Programme\MIOS_base/include/asm -I C:\Programme\MIOS_base/include/share -I C:\Programme\MIOS_base/modules/app_lcd/dummy -DDEBUG_MODE=0   C:\Programme\MIOS_base/modules/app_lcd/dummy/app_lcd.asm -o _output/app_lcd.o
sh C:\Programme\MIOS_base\bin/mios-sdcc -c -mpic16 -p18f452 --fommit-frame-pointer --optimize-goto --optimize-cmp --disable-warning 85 --obanksel=2  -I./src -I C:\Programme\MIOS_base/include/c -I C:\Programme\MIOS_base/include/share -DDEBUG_MODE=0  main.c -o _output/main.o
C:\Programme\MIOS_base\bin/mios-gpasm modifies _output/main.asm, result in _output/main__mios-gpasm-tmp.asm
gplink -s C:\Programme\MIOS_base/etc/lkr/p18f452.lkr -m -o project.hex  C:\Programme\MIOS_base/lib/libsdcc.lib C:\Programme\MIOS_base/lib/pic18f452.lib _output/mios_wrapper.o _output/app_lcd.o _output/main.o
error: missing definition for symbol "_parse_sysex", required by "_output/main.o"
make: *** [project.hex] Error 1
<<< Process finished.
================ READY ================

/edit: removed remaining code, as error had nothing to do with it

i would be glad if you could help me out!

Thnx & Cheers :)

Alex

test.rar

test.rar

[avogra]

ok, got it :)

when reading through the post once more, i realised, sdcc didn't even try to compile a midi_process.o, so added this to the makefile and everythings fine now.

i thought, i had read somewhere, that the latest release looked after this automatically. but suppose i got something wrong there.

Cheers,

Alex

[avogra]

horray!!!

*dancing the it's-working-dance* :D

yesterday i finished everything, i really need. my core now translates the odd velocity response of my stage-piano to sensible values and catches most buttons from its control-surface. those are used for preset-changes, midi-channel switching and effects on/off.

most buttons on the stage-piano send a really ugly mixture of BS+PC, CC and sysex-messages. unfortunately, i cant ignore those, as other buttons send the exactly same sysex-msgs only. the code is quite a patchwork :P

10 of those buttons are then used to send the BS+PC msgs, my expander wants to see. pressing multiple times allows access to higher presets. another 2 buttons allow to change the midi-channel (resp. patch on the expander), notes and damper-CC are sent on. when a note-on is received, the box remembers the channel for each key. note-offs are then sent on the same channel. same for damper. that way i can play e.g. a chord, hold it (or use damper) and change the channel. while playing the new patch, the chord will sustain until i release keys (or damper). the 2 remaining buttons are used for all-sounds-off and toggling an effect on the expander (sysex-msg). quite trivial, but gives me a whole bunch of new options :)

ultimately, i came to the conclusion, that already now, i won't need the floorboard anymore 8)

next thing will be a propper housing. then, im thinking about using ordinary buttons and a DIN instead of the ugly button-processing. and somehow a lcd feels like a must, although i dont really need it  :)

so all together, nothing special in here. most of it is not even reusable, but it's already doing a great job for me!

cu, Alex