Author Topic: Pin identification for Belton BTDS20 Digital Rotary switch  (Read 4311 times)

kkillebrew

Hello,

I just got a Profusion RA-FX16G digital effects module for guitar amps, and along with it a Belton Digital Rotary switch BTDS20.  The datasheet indicates which pin numbers to use when connecting the board to the switch, but there are no markings on the switch as to which pin is which.  There are 8 pins on the switch and one digital ground.  Nowhere on the switch data sheet does it give pin number identifiers.  It's a 4 bit grey code switch.  Is there some pin numbering standard?

Anyone tried this module?  Has 16 different effects, costs about $30 plus $5 shipping from the UK.  I want to experiment but how do identify the switch pin numbers?

MetalGuy

Re: Pin identification for Belton BTDS20 Digital Rotary switch
« Reply #1 on: March 26, 2011, 06:03:12 PM »
I checked the datasheet for this encoder and it really doesn't say much. I suppose you have 8 pins because you have 2 wafers. Something like a "stereo" encoder.
In a Grey code encoder you'll need five pins altogether. If you don't know which one is which try connecting them one after another to the board. If effects don't change in the expected order just reverse the pins.
I used this one in my Femtoverb project (check out the thread):

http://www.alliedelec.com/search/productdetail.aspx?SKU=7530115

The other option is to identify the ground pin and write down the code table by measuring each pin for 1 or 0 in each position and them compare it to the Grey code table to figure the pins.

kkillebrew

Re: Pin identification for Belton BTDS20 Digital Rotary switch
« Reply #2 on: March 27, 2011, 11:48:34 AM »
Okay I found a datasheet that shows pin 1 2 3 4 and C for the switch, I guess the other pins are not used.  The datasheet for the FX module shows five connections to a grey code switch labeled Ground 1 2 4 and 8. Perhaps the 8 is a typo for 3? 


http://www.profusionplc.com/images/data%20sheets/ra-fx16g.pdf

MetalGuy

Re: Pin identification for Belton BTDS20 Digital Rotary switch
« Reply #3 on: March 27, 2011, 04:23:57 PM »
Connect the encoder to the module as shown and observe if it changes programs as per datasheet. If not just turn it the other way and connect again.

kkillebrew

Re: Pin identification for Belton BTDS20 Digital Rotary switch
« Reply #4 on: March 27, 2011, 06:13:54 PM »
I figured it out.  The DSP data sheet had pinouts from an older belton encoder.