Add support for Roland five byte device codes in check sums

Question

MIDI Target Manufacturer(s): Roland

Roland has run out of four byte device codes and now gone to five byte.  Juno-X is five byte (00 00 00 00 12).  Not urgent update, as I do not believe the Juno-X enforces checksum validity.  But the Tr-6s (00 00 00 6D - near end of four byte codes) does.  So may not be long before we see a Roland device that needs  a correct five byte address checksum to function with MD.  At present, if you are coding for a Juno-X, select the four byte option.  

Let us know if you have a newer Roland device that is not responding to MD, and we can investigate if it is a checksum issue.

Schoolcall - for those interested, the Roland checksum calculation is:

• Sum address and data bytes
• Mod sum with 80h (128)
• Subtract sum from 80h 
• Mod sum with 80h

The selection in the SysEx field (Roland two, three, four...) lets MD know where the address begins for the summation.

Comments

This is shocking but... ok. We'll implement. Thanks for this and the SB workaround below!

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going to beta now.

Answer 1

MIDI Target Manufacturer(s): Roland

We have our first board that needs this fix - Roland SPDX-Pro.

Here is a StreamByter output rule that fixes the checksum for this device.  I don't have a five byte device to test against, but this returned correct checksums for my test matrix.

In the MD control SysEx format, select one of the current Roland checksum formats to ensure the message has a checksum.  Doesn't matter which as this does a complete checksum recalc.  We just need the CS position to exist in the message.

Update - original incorrectly had 12 in ID position five - correct value for SPDX Pro is 16

Paste from line below to bottom in StreamByter output rules

# Temporary fix for Roland five byte device ID checksums
# Red Heron Music
# March 8, 2024

# SPDX Pro sample two byte data message
# F0 41 10 00 00 00 00 16 12 20 00 00 41 V1 V0 Cs F7
#  0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F 10 (ML = 11)

# Checksum calculation starts at position M0A, goes to ML - 3, checksum in position ML - 2

# i0 - CheckSum
# i1 - Loop variable 
# i2 - Last position

If Load
    Alias i0 ChkSum
    Alias i1 Loop
    Alias i2 Last
End

If M0 == F0 41 10 00 # Roland Device
    If M4 == 00 00 00 16 # SPDX Pro, replace 16 for other Roland five byte devices

        Ass ChkSum = 0
        Ass Loop = 9
        Mat Last = ML - 2 # Checksum position

        While Loop < Last # we get ML - 3 by using < in test
            Mat ChkSum = ChkSum + Mi1 # Loop - alias not allowed on indirect
            Mat Loop = Loop + 1
        End

        Mat ChkSum = ChkSum % 80
        Mat ChkSum = 80 - ChkSum
        Mat ChkSum = ChkSum % 80

        Ass Mi2 = ChkSum # Last - Alias not allowed on indirect
    End
End

Answer 2

MIDI Target Manufacturer(s): Roland

We have our first board that needs this fix - Roland SPDX-Pro.

Here is a StreamByter output rule that fixes the checksum for this device.  I don't have a five byte device to test against, but this returned correct checksums for my test matrix.

In the MD control SysEx format, select one of the current Roland checksum formats to ensure the message has a checksum.  Doesn't matter which as this does a complete checksum recalc.  We just need the CS position to exist in the message.

Update - original incorrectly had 12 in ID position five - correct value for SPDX Pro is 16

Paste from line below to bottom in StreamByter output rules

# Temporary fix for Roland five byte device ID checksums
# Red Heron Music
# March 8, 2024

# SPDX Pro sample two byte data message
# F0 41 10 00 00 00 00 16 12 20 00 00 41 V1 V0 Cs F7
#  0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F 10 (ML = 11)

# Checksum calculation starts at position M0A, goes to ML - 3, checksum in position ML - 2

# i0 - CheckSum
# i1 - Loop variable 
# i2 - Last position

If Load
    Alias i0 ChkSum
    Alias i1 Loop
    Alias i2 Last
End

If M0 == F0 41 10 00 # Roland Device
    If M4 == 00 00 00 16 # SPDX Pro, replace 16 for other Roland five byte devices

        Ass ChkSum = 0
        Ass Loop = 9
        Mat Last = ML - 2 # Checksum position

        While Loop < Last # we get ML - 3 by using < in test
            Mat ChkSum = ChkSum + Mi1 # Loop - alias not allowed on indirect
            Mat Loop = Loop + 1
        End

        Mat ChkSum = ChkSum % 80
        Mat ChkSum = 80 - ChkSum
        Mat ChkSum = ChkSum % 80

        Ass Mi2 = ChkSum # Last - Alias not allowed on indirect
    End
End