ComputerVoltageSources

I think the display sharing the MIDI port via a sysex strig is VERY clever.
It also allows a very simple two pin interface on the main board.

A more serious problem is the lack of a datasheet for the 28 pin version of the Basic Atom 
Pro. I called Basic Micro and they said to use the 28 pin plain Basic Atom as a reference.

Also, I think we should support the 40 pin footprint, in case the 40 pin version of the Basic 
Atom Pro ever shows up.

--- In ComputerVoltageSources@yahoogroups.com, "djbrow54" <davebr@...> wrote:
>
> Just spent some time on the phone with John Loffink discussing the 
> various display options.  To summarize, I think there are three basic 
> parameters that need to be defined.
> 
> 1) Display size.  How many rows and how many characters? 
> Considerations include backlight power and module width.  These 
> modules are much larger than their display area.  A 8x2 will fit in a 
> 1U module.  You can probably find some 16x2 that will fit into a 2U 
> module.  The microcontroller could be implemented to support either 
> format with an additional input mode select pin.
> 
> 2) Electrical interface.  You want to use the 14 pin parallel 
> interface LCDs to best maximize availability.  You don't want to use 
> this many pins as the AtomPro has limited I/O.  Using the AtomPro LCD 
> commands requires that you use 7 pins for the display which is still 
> too many.  SPI and serial are options to reduce the number of pins 
> used.  SPI could be shared with the DAC by using another I/O pin as 
> the chip select.  This obviously would not be retrofitable or code 
> compatible to the PSIM.  Another option is sharing hardware serial 
> with MIDI (as I implemented with a MIDI sysex command).  Again, 
> multiple modes could be implemented with an additional input mode 
> select pin (I implemented both 57600 serial and MIDI sysex in my 
> microcontroller)
> 
> 3) Prototcol.  How do you want to communicate with the LCD?  Do you 
> want general purpose cursor positioning?  Do you even want a cursor (I 
> turned it off on the 8x2 to save a character space).  Do you want 
> scrolling?  Do you want the second line to be contiguous with the 
> first, or, is overwrite mode sufficient.  Do you want horizontal 
> scrolling?  (I chose contiguous lines with both scrolling and 
> overwrite. I also did not implement general cursor position commands 
> but rather start of line1, start of line2, back 1 position, & forward 
> 1 position)
> 
> 4) Additional features.  With a microcontroller you can use additional 
> pins for extra features.  I added 4 digital outputs to expand my PSIM 
> capability and also a MIDI status LED.  Most anything is possible.
> 
> Here are some links of possible interest (sorry, they will be long).
> 
> PSIM in 2U MOTM format showing number of pots, connectors, & switches:
> modularsynthesis.com/modules/synthmodules/synthmodules.htm
> 
> 8x2 display in 1U MOTM format:
> modularsynthesis.com/modules/synthmodules/PSIM-Display/PSIM-Display.
> htm
> 
> Partway down this page is a link to my display controller spec:
> modularsynthesis.com/modules/synthmodules/PSIM-Display/DJB-
> PSIM%20LCD%20display%20spec.pdf
> 
> 20x2 display in external package (e.g. too large to panel mount):
> modularsynthesis.com/display/display.htm
> 
> Comments?
> 
> Dave
>