Description of the files:
-------------------------

The archive ret_diy.zip contains the following files:

readme.txt    = this text
ret_sch.pcx   = ReTurn v1.0 schematics (600x600 dpi)

r8_lay.pcx    = layout r8 (300x300 dpi)
r8_comp.pcx   = component placement plan r8 (600x600 dpi)
r8_list.txt   = list of components r8
r8.jpg        = picture of assembled r8 board

r8p_lay.pcx   = layout r8p (300x300 dpi)
r8p_comp.pcx  = component placement plan r8p (600x600 dpi)
r8p_list.txt  = list of components r8p
r8p_fp.pcx    = front panel drilling plan r8p
r8p.jpg       = picture of assembled r8p board


The above files contain information on building a ReTurn v1.0 MIDI Controller.

Board layout:
-------------

There are 2 different board layouts for the ReTurn device:

- r8: This is the standard layout for a single-sided processor/ADC board 
      (size: 10x8cm) with a connector for external rotary or slide
      potentiometers, LEDs and push-button.
      You should choose this board layout if you want to design your own 
      case and front panel layout or if you want to integrate the ReTurn 
      system into an existing device or instrument.

- r8p: This layout includes all components (including rotary pots/excluding
       LEDs and button) on one single-sided board (size: 10x16cm).


Although this may not exactly be the project to begin your electronics career
with, it should not be much of a problem for people with basic electronics
skills. Note that the jumpers (JPxx) have to be inserted before anything else.
You should use sockets for all ICs (at least for U1 because of possible
firmware upgrades). You do not necessarily have to use 47k potentiometers, 
the system has been successfully tested with pot values ranging from 10k to 
approx 100k. If you do not want to make a pcb (etching, drilling etc), you can 
also build the circuit on a veroboard.

The snapshot function will only work properly if a quality push-button switch 
with precise tactile feel (preferably a panel mount microswitch) is used (SW1).

The connection wires between the r8-PCB and the pots should not be longer than
30cm.

If you build the r8p-version, note that the pots have to be inserted from the
soldering side and screwed on the component side.

The latest firmware for the Atmel 89C2051 MCU (U1) is available from 
http://come.to/re_turn
This firmware file has to be programmed into U1. You need an Atmel programmer
to do this. If you do not have one, just search the net, there are many free 
DIY plans available. 

Once the PCB is finished and tested, you can put it into any plastic or 
metal case of your choice. The front panel drilling plan for the r8p-version
only marks the positions of the pots, LEDs, push-button and screws. The 
diameters of the drill holes depend on the actual sizes of the parts used.

Important:
Please take all necessary precautions before handling ESD-sensitive
semiconductor devices.


Important note for printing the .pcx images:
----------------------------------------------
To print the layout image, use a paint program that is able to scale the
printer output (eg Paint Shop Pro). This is NOT possible with the Windows
"Paint" program. Set the following values (eg in Paint Shop Pro's "Page 
Setup"):

r8_lay.pcx:   Width           =  80 mm
              Height          = 100 mm
              "Use Full Page" = Off

r8p_lay.pcx:  Width           = 100 mm
              Height          = 160 mm
              "Use Full Page" = Off

r8_comp.pcx:  Width           =  80 mm
              Height          = 100 mm
              "Use Full Page" = Off

r8p_comp.pcx: Width           = 100 mm
              Height          = 160 mm
              "Use Full Page" = Off

r8p_fp.pcx:   Width           = 110 mm
              Height          = 174 mm
              "Use Full Page" = Off

ret_sch.pcx:  "Maintain Aspect Ratio" = On
              "Use Full Page"         = On



Copyright (c) 2002 Thomas Brandl
Email: tbrandl@rocketmail.com