[Coco] BIGGEST PROBLEM

[Allen Huffman]

> On Mar 6, 2017, at 10:23 AM, David Ladd <davidwladd at gmail.com> wrote:
> 
> This is a nifty option for sure.  There are some other options out there
> to Allen.  The PJRC Teensy 3.2 & 3.5 are 5v tolerant on the digital input
> pins.​  The Teensy 3.2 is 72MHz ARM micro controller and the Teensy 3.5 is
> also a ARM micro controller, but it is 120MHz.

I haven't worked with the bigger Teensy's, due to cost, but do have the 2.0 for my original iCade (iOS) joystick projects.

> The Teensy 3.2 on the bottom shows something about a USB Host Mode, but I
> haven't messed with that part of the Teensy.

I will look in to this. They may have built in that MAX chip and rely on the USB Host library that Circuits at Home published.

Actually, scanning their website only lists the USB device mode (where the Teensy appears as a USB device to a host PC). That's why I got the Teensy -- it had keyboard, mouse and joystick support built-in, while the Arduino Leonardo only did keyboard and mouse.

However, a cheap $5 Arduino with the $4 USB host chip will still be cheaper. 

> As far as the joystick ideas I just ran across some I2C 12bit DAC's which
> can be wired to a VCC of 2.7 to 5.5V.  The boards I can across can be set
> to a high address or low address space.  Should be able to use two of them
> on the same I2C buss, but my know how on this is nothing.  So someone who
> is use to using I2C might have better luck.  So possibly using the DAC's to
> send a analog signal into the analog inputs on the CoCo's joystick port
> MIGHT be possible, but I am no engineer either.

That would be nice - that would save a chip from my design, where I am using a programmable potentiometer, basically.

> Another side note in relation to the I2C DAC's besides being able to use
> the Arduino's I2C libraries might be possible to use those I2C DAC's on the
> Raspberry Pi as well.  Since the Raspberry Pi has a I2C buss.  Hmmmm anyone
> tried this yet?

Linux is what gets in the way. Without realtime, it could be off doing something else and miss messages. The code I looked at seemed to halt the system or something to bash the I2C bus.

I was experimenting with various addressable RGB LEDs (WS2811, LPN8806, etc.) and the Pi was lacking in its support ability due to the overhead of a non-realtime OS, but folks were still able to get it working ;-)

		-- A