mbhp core stm32f4 ( J19 question )

[Navicat]

Hello everyone.

 

I want to connect another DIN & DOUT chain on mbhp core stm32f4.

It is possible to drive J19 to work as J8/9??

 

Best Regards, Tilemachos

 

[ilmenator]

Why don't you extend the chain that you already have? How many shift registers does the first chain have?

[Navicat]

Here is my plan of the DOUT to R-2R DAC. I need 4 more CV Outs like this!

 

Take a look : http://www.docdroid.net/ri8z/dout-cv.pdf.html

 

________

 

Update:

 

Here is my project (not finished). It is a TR-808 Midi Interface with velocity outputs. Take a look!

I need the extra DOUT chain for some more CV Outs for the velocity and the rest Dout channel for trigger voices with +5v

 

http://www.docdroid.net/rj0u/tr-808-midi-interface1.pdf.html

 

Regards Tilemachos

Edited February 11, 2015 by Navicat

[ilmenator]

Well I guess you could clone J8/9 to J19, but at the cost of decreased performance and all other kinds of hassle. Also, I am not sure your design of using one complete DOUT shift register for each velocity output is a good choice - value changes for different outputs won't happen simultaneously, but as the values shift through the registers. That might give you some artefacts that you'd ratrher not want to see there.

 

How about using digital potentiometers instead? I have never tried that myself, but there is a tutorial on digipots here, the hardware is pretty straight forward to implement and in terms of coding the example provided by TK seems to be manageable as well.

[Navicat]

Yeah my main idea was to clone j8/9 at j19 :)

It was in my mind digipots and thank you for the tutoria link.

I think digipots is a good idea and more reliable in theory.. I must squeeze my mind on how to make it!

Thank you very much!

I will give a try! If you have ideas like this or a complete solution to my problem i can't wait to message me!

Thanks again.

Regards Tilemachos

[Navicat]

Well I have an idea!

 

I'll make a daisy-chain of 4  AD5204—4-channel Digipot ---> http://www.analog.com/static/imported-files/data_sheets/AD5204_5206.pdf

That makes 16 Digital Pots.

AD5206 —- 6 channel Digipot does not allow Daisy-chain :brr:

The chain will be connected at J19.

 

A doutx4 will be connected at J9.

The first 16 shift register outputs of the Dout will go in each Terminal A pin of each digipot.

All Terminal B pins will connected to ground.

Finally the Wiper pin of each digipot will be my CV OUT. A voltage will be produced between 0..+5v

 

For my purpose i will drive this signal thru a Noninverting TL-072 with +15 to make the signal 0...+15v as i did in the previous schematic.

You think that this will work? I think it is really faster,more reliable and with 256-position pot will have high resolution.

Edited February 12, 2015 by Navicat