Help with SysEx string formatting for Roland DEP-5 panel

[Bennettistas]

Hello everyone,

I'm currently building a Ctrlr panel for the Roland DEP-5, and I’ve been able to make some progress—basic MIDI communication is working, and I can send and receive SysEx data to/from the unit. However, I’m struggling with how to correctly format the SysEx strings in the "Custom MIDI Message" field of each modulator.

I understand the basics, like using F0 ... F7, and that I can insert variables like ms, ls, or value where needed. But I’m not entirely sure how Ctrlr handles these internally, or how to correctly position the value bytes inside the message. Also, how do I handle fixed bytes that shouldn’t change (should I use XX for those?), and how do I ensure the checksum is calculated correctly?

For example, I want to control the Reverb Time parameter, which seems to be located at a specific byte offset in the DEP-5’s All Parameter Receive (APR) message format. Here's the SysEx structure I’m using:

F0 41 35 00 52 20 01 <0X XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX ms ls XX XX> F7 <string

The format in the manual is set to 0vvv vvvv : 0vvv vvvv (in a 24 bytes format string), and in this case what I want to change is in the bytes 21/22. It's says something about nibble pairs, but I really don't understand.
Can somebody help me with this?
Thanks in advance!

[pedroxi]

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On Sat, May 24, 2025, 04:45 Bennettistas ***@***.***> wrote: Hello everyone, I'm currently building a Ctrlr panel for the Roland DEP-5, and I’ve been able to make some progress—basic MIDI communication is working, and I can send and receive SysEx data to/from the unit. However, I’m struggling with how to correctly format the SysEx strings in the "Custom MIDI Message" field of each modulator. I understand the basics, like using F0 ... F7, and that I can insert variables like ms, ls, or value where needed. But I’m not entirely sure how Ctrlr handles these internally, or how to correctly position the value bytes inside the message. Also, how do I handle fixed bytes that shouldn’t change (should I use XX for those?), and how do I ensure the checksum is calculated correctly? For example, I want to control the Reverb Time parameter, which seems to be located at a specific byte offset in the DEP-5’s All Parameter Receive (APR) message format. Here's the SysEx structure I’m using: F0 41 35 00 52 20 01 <0X XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX ms ls XX XX> F7 <string The format in the manual is set to 0vvv vvvv : 0vvv vvvv (in a 24 bytes format string), and in this case what I want to change is in the bytes 21/22. It's says something about nibble pairs, but I really don't understand. Can somebody help me with this? Thanks in advance! — Reply to this email directly, view it on GitHub <#722>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAM4MBOFBCODUWKNP5G6LGT3ABLT7AVCNFSM6AAAAAB52PA3ISVHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZYGM3DOOJRGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[damiensellier]

Do you have a link to the manual and sysex messages?

[Bennettistas]

Hi @damiensellier ! Thank you for answering. Here is the manual: https://cdn.roland.com/assets/media/pdf/DEP-5_OM.pdf
I figure out how to send some comands and something is working. The mode of the DEP-5 works only in APR mode, so all the parameters (24 bytes) have to be sent at once, but unfortunally the unit doesn't send sysex strings to recall memory, or read the actual state of the knobs. I'm thinking in a solution somehow related to memory buffer maybe? I've found Ctrlr about 3 days ago and already doing lua scripts for this. The sysex format is this one (confirmed) F0 41 35 00 52 20 01 XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX F7, the nibble pairs of data are always 0 in the first hex of both bytes, so the "real" byte readed is composed by the second hex of each byte (0000xxxx 0000yyyy = xxxxyyyy is what the unit reads). Hope this help and thanks in advance!

[Bennettistas]

I'm looking a way to write in buffer memory all the knobs, or set a snapshot when loading 1st time (I don't know how yet...) and I don't know if there is any way to ignore bytes in the sysex string, I've read something about "${ii}" or "ii" but no luck with that...

[Bennettistas]

The unit doesn't need checksum, so I think at least that one was easy... =D

[damiensellier]

https://cdn.roland.com/assets/media/pdf/DEP-5_OM.pdf

Page 50

[dnaldoog]

Hi @Bennettistas

It looks like the data for a parameter is sent as 4 bit nibbles.

As you say, from the manual it looks like 24 parameters are all sent out as one message. So it's probably best to do that in a lua callback function:

(1) First name all your modulators exactly as in the manual. From experience this works best - forward slashes etc are fine
(2) Create a lua table with all 24 parameters as values:
(3) Use a helper function to convert parameters to 4 bit nibbles (create4n())

---

parameters = {
    "REVERB SELECTION",
    "OUTPUT LEVEL",
    "Q OF MIDDLE FILTER",
    "FREQUENCY OF MIDDLE FILTER",
    "BOOST/CUT OF LOW FILTER",
    "BOOST/CUT OF MIDDLE FILTER",
    "BOOST/CUT OF HIGH FILTER",
    "FEEDBACK OF CHORUS",
    "RATE OF CHORUS",
    "DEPTH OF CHORUS",
    "ALGORITHM",
    "PRE DELAY or DELAY TIME",
    "REVERB TIME or FEEDBACK OF DELAY",
    "HF DAMP or GATE TIME"
}

function sendData()
    --create a Memory Block (data to send)

    local channelOut = panel:getProperty("panelMidiOutputChannelDevice") - 1
    local m = MemoryBlock("F0 41 35 00 52 20 01")
    m:setByte(3, channelOut) -- set the channelOut
    for i, v in ipairs(parameters) do -- now get all the values as 4 bit nibbles
        local value = panel:getModulatorByName(v):getModulatorValue()
        if i > 4 then -- create nibbles -- add each 4 bit nibble set to the message
            local msb, lsb = create4n(value)
            local tmp = MemoryBlock(string.format("%.2x %.2x", lsb, msb)) -- note lsb is first
            m:append(tmp) -- add each 4 bit nibble set to the message
        else -- not a split number
            m:append(MemoryBlock(string.format("%.2x", value)))
        end
        m:append(MemoryBlock("F7")) -- EOX
    end
        panel:sendMidiMessageNow(CtrlrMidiMessage(m:toHexString(1)))
end


-----------------------------------------------------------------
function create4n(n) -- convert integer into two 4 bit nibbles
    local bv = BigInteger(tonumber(n))
    return bv:getBitRangeAsInt(4, 4), bv:getBitRangeAsInt(0, 4)
end

Done!

Now if you need to decode 4 bit nibble incoming you can use this function:

function combine4n(a, b) -- convert two 4 bit nibbles to a single integer
    local m = bit.lshift(a, 4)
    return m + b
end

Roland DEP-5 sendData_1_0.zip

[Godlike-Productions]

One thing to be wary of is data rate with SYSEX packages, especially for older synths, and where you want to modulate a parameter. On the Jupiter 8 panel I built, I did a similar thing where I sampled all of the Ctrlr modulators, built the sysex message and sent it, but I had to limit the rate using a callback function. Triggering it straight from the modulator sent so much sysex that it crashed the Jupiters Z80.

If you are scrolling to a new value and just setting it, then the mouseUp function is the go, if you want to modulate controls from your DAW, you'll need to build a custom function to limit the rate.

[dnaldoog]

...and then recommended to send all MIDI when using a mouseUp event on each of the 14 controls.

Mouse Up Send All Roland-DEP5.zip

[damiensellier]

As simple as it can be! Hope the OP will appreciate ;)

[dnaldoog]

That mouseUp function with uiSlider is an excellent addition to CtrlrX!