MB808 from the begining, sources of info

MIDIbox SEQ
21

Yes, just the MB-808 firmware with a special configuration which enables 13 CV outputs (for velocity) at 6bit resolution - the 74HC595 based DACs are part of the PCB as well:

http://svnmios.midibox.org/filedetails.php?repname=svn.mios&path=%2Ftrunk%2Fapps%2Fsequencers%2Fmidibox_808%2Fsetup_seq_dr_default.asm

 

Best Regards, Thorsten.

22

Nice… a frontpanel too

I am very happy to see progress

Does velocity works with uLarge boards too?

 

best regards

 

Antonio

23

Midibox DR? Looks very nice. Is this upcoming stuff being discussed offline or somewhere other than the forum?

24

This would be great for the second bare board I have.  Any plans for a group build/buy?

25

Yes, MIDIbox DR has been discussed offline. As far as I know, Al is planning to provide the PCB in a bulk order.

But please show patience - we are discussing this since January 2012! :wink:

 

Best Regards, Thorsten.

26

Patience…my second name

 

Thorsten  are there some schematic to see how velocity will work .

 

DACs will drive  VCAs ?

 

Best regards

 

Antonio

27

It’s a simple DOUT based DAC, the ASCII based schematic can be found in the setup_* files (e.g. http://svnmios.midibox.org/filedetails.php?repname=svn.mios&path=%2Ftrunk%2Fapps%2Fsequencers%2Fmidibox_808%2Fsetup_seq_dr_default.asm )

 

;; CV values can also be output via DOUT shift registers
;; This option is sufficient to control the "velocity" of drum instruments, and it's cheap as well!
;; We expect following connections:
;; 
;; DOUT 160k
;; D7 ---o---/\/\/\---*
;; 80.6k |
;; D6 ---o---/\/\/\---*
;; 40.2k |
;; D5 ---o---/\/\/\---*
;; 20.0k |
;; D4 ---o---/\/\/\---*
;; 10.0k |
;; D3 ---o---/\/\/\---*
;; 5.1k |
;; D2 ---o---/\/\/\---*----o CV Out
;; 220 Ohm
;; D1 ---o---/\/\/\--------o free assignable trigger
;; 220 Ohm
;; D0 ---o---/\/\/\--------o another free assignable trigger
;; 
;; The DOUTx channels are matching with the AOUT channels as specified in the DEFAULT_TRKINFO table above.
;; Allowed values: 1-16 (selects DOUT shift register) or 0 to disable
;; Ensure that DEFAULT_NUMBER_SR is high enough so that all DOUTs are updated.
#define DEFAULT_CV_DOUT_SR1 4
#define DEFAULT_CV_DOUT_SR2 5
#define DEFAULT_CV_DOUT_SR3 6
#define DEFAULT_CV_DOUT_SR4 7
#define DEFAULT_CV_DOUT_SR5 8
#define DEFAULT_CV_DOUT_SR6 9
#define DEFAULT_CV_DOUT_SR7 10
#define DEFAULT_CV_DOUT_SR8 11
#define DEFAULT_CV_DOUT_SR9 12
#define DEFAULT_CV_DOUT_SR10 13
#define DEFAULT_CV_DOUT_SR11 14
#define DEFAULT_CV_DOUT_SR12 15
#define DEFAULT_CV_DOUT_SR13 16
#define DEFAULT_CV_DOUT_SR14 0
#define DEFAULT_CV_DOUT_SR15 0
#define DEFAULT_CV_DOUT_SR16 0

 

Best Regards, Thorsten.

28

Thanks Throsten for this!

Dout to CV!

 

A question for this..

The output voltage is between 0v and +5V right??

 

If yes is there a way to make this work between 0v and +15?

 

Or far away better for TR-808: Accent = Trigger pulse between +5v and +15v

My target is to make a Dout Trigger pulse of 1ms width between +5v and +15v ( This will be the accent for 808 voices )

 

Update:

I know i need a shift register that will be operateable at 15 volts..

I found that http://www.ti.com/product/cd4094b can operate at those voltages but this is not a 3-state output register.. Is this a problem?

 

Regards, Tilemachos