BlackIce and planned BlackEdge and my* products all have mixed signal support, both analogue and digital, this is an important feature for all myStorm products and matches many real world application requirements. Therefore one of the elements we need to decide how to proceed on is how to expose these interfaces in standardised ways.
I have a none Pmod based carrier design (more later) aimed at more robust forms of expansion for robotics, automation and industrial applications, but it would be good to build on existing Pmods for general purpose development. Thus if we are to focus on a Pmod based carrier for example how could we expose the analogue signals to make them useful? There are a couple of possibilities I have thought about so far :
- Use dedicated analogue Pmods either single or double where all non power pins become analogue pins.
- Use the space in between a pair of double Pmods to insert some extra analogue pins.
The first is self explanatory but the second requires a bit more enumeration; if 2 rows of 3 x 0.1" headers are inserted between 2 existing double (adjacent) Pmods you end up with a dual row (2 x 15) 0.1" 30 pin right angled female header, with a pinout looking into it as :
+3v3,GND,D01,D02,D03,D04 A1,+5V,A2,3v3,GND,D05,D06,D07,D08
+3v3,GND,D09,D10,D11,D12 A3,GND,A4,3v3,GND,D13,D14,D15,D16
I.e. 16 digital, 4 analogue signals, +3v3, +5v, and ground.
This would still accept standard dual double Pmod peripherals, individual Pmods (single or double) or the new mixed signal peripheral lets call them Mixmods. This would enable one to build new mixed signal adaptors and plugins whilst maintaining backward compatibility with Pmod peripherals on the carrier, It also provides +5v which many think is missing from the Pmod standard.
So consider this the start of the conversation on Mixed Signal Pmod interfacing, please let us know your ideas to solve this challenge and any thoughts on our suggestions here..
