Manipulating Snapshot Files

The XML files that are created by the ER-101 Programmer are easily generated and modified if you are comfortable with XML and even easier if you are comfortable with .NET/C#. While this page is a bit sparse at the moment, I will try to collect here knowledge and utilities for would-be hackers of ER-101's snapshot files.

The ER-101 Common Library: this is the same library (as a Visual Studio C# project) that the ER-101 Programmer uses to parse and generate snapshot files. You will want to start with the LoadFromXML(...) and SaveToXML(...) methods in the ER101 class.
Download an example of a snapshot file from here.

Uploading voltage tables that you created elsewhere...

Yes it is completely possible to design your voltage tables on the computer and upload them via USB to your ER-101. It just involves a little familiarity with XML files:

1. Using the ER-101 Programmer application, download your ER-101's snapshots as one large XML file.

Download the application from here: http://www.orthogonaldevices.com/er-101/Programmer

2. In the XML file there is a "snapshots" node that contains 16 "Snapshot" child nodes, one for each of the snapshots on your ER-101. Each "Snapshot" node contains a "tracks" node with the following structure:

<tracks>

    <Track>
        <voltagesA>
            (voltage values here)
        </voltagesA>
        <voltagesB>
            (voltage values here)
        </voltagesB>
    </Track>

    <Track>
        <voltagesA>
            (voltage values here)
        </voltagesA>
        <voltagesB>
            (voltage values here)
        </voltagesB>
    </Track>

    <Track>
        <voltagesA>
            (voltage values here)
        </voltagesA>
        <voltagesB>
            (voltage values here)
        </voltagesB>
    </Track>

    <Track>
        <voltagesA>
            (voltage values here)
        </voltagesA>
        <voltagesB>
            (voltage values here)
        </voltagesB>
    </Track>

</tracks>

Notice there are 4 tracks and each track has two voltage tables (A and B). The values in voltage table are the actual 16-bit integers that are sent to the DAC (0 corresponds to 0.000V, 8000 corresponds to 1.000V and so on). You can edit the values with a text editor or custom script and then upload the modified XML file back to your ER-101 (again using the Programmer application).

-- Some formulas to help you create your own voltage tables --

The basic equation for converting frequency to voltage:

frequency = (frequency of C0 or 16.35Hz) * (2 ^ voltage)
voltage = log2 (frequency/16.35)

The basic equation for converting cents to voltage:

cents = voltage/1200
voltage = cents*1200

The basic equation for converting voltage to a DAC code that goes into the voltage table:

code = voltage*8000

3. Once you have your modified snapshots back in your ER-101, you can copy the voltage tables to other tracks or even to the USER reference voltage tables.

FYI, the ER-102 makes this process a lot simpler because the reference voltage tables are actually just individual files on your SD card.