-
-
Notifications
You must be signed in to change notification settings - Fork 16
Protocol
This document describes the protocol used to communicate with an RME Fireface UCX II over USB. The primary focus is when the interface is is class-compliant mode, but some details about the normal USB mode are mentioned as well.
The protocol details were obtained by inspecting USB traffic between TotalMix FX (version 1.86) and a UCX II. For CC-mode, the iPad version of TotalMix FX was used; a Raspberry Pi and Linux's USB gadget MIDI function were used to capture the SysEx packets. See Capture for more details.
This document is not official in any way, and the information presented here may be subtly off, or just plain wrong.
Class-compliant mode uses the "Port 1" MIDI port to control the device using System Exclusive packets. Each packet has the following format:
Manufacturer ID
|
/------\
F0 00 20 0D 10 <subid> <payload> F7
| | |
SysEx start Device ID SysEx end
The payload consists of a sequence of 32-bit integers. SysEx packets can only contain bytes with the high bit unset, so each 32-bit integer in the payload is encoded as five 7-bit bytes in little endian.
For example, the number 0x1A2B3C4D is encoded as follows:
1A 2B 3C 4D
00011010 00101011 00111100 01001101
0001 1010001 0101100 1111000 1001101
01 51 2C 78 4D
4D 78 2C 51 01
Sub ID 0 is used by the host to set registers, and by the device to notify the host of changes to registers. In this case, each 32-bit integer in the payload contains the register in bits 16-30, and the value in the lower 16 bits. The high bit is used as a parity: it is set if and only if the number of set bits in the register and value is even.
To enable mute of output channel 3, we need to set register 0x0582 to value 0x0001. There are 5 set bits in these integers, so we do not set the high parity bit. Thus, we encode as a single 32-bit integer 0x05820001, which is then encoded as a sysex payload:
05 82 00 01
00000101 10000010 00000000 00000001
0000 0101100 0001000 0000000 0000001
00 2C 08 00 01
Now, assembling the sysex packet with sub ID 0:
F0 00 20 0D 10 00 01 00 08 2C 00 F7
| \---Payload--/
Sub ID
Sub ID 2 is used by the host with an empty payload to request current level information. In response, the device sends packets with sub IDs 1-5, each containing level information. The format of data in the level packets is as follows:
[<channel 1 rms low 32 bits> <channel 1 rms high 32 bits> <channel 1 peak>]...
Sub IDs 1 and 4 contain levels for the input channels (post-FX and pre-FX respectively), sub IDs 3 and 5 contain levels for output channels (pre-fader/FX and post-fader/FX), and sub ID 2 contains levels for the playback channels.
Peak levels are given as a 32-integer with the following format:
[0:3] 0xF if overload, otherwise 0
[4:27] 24-bit peak level
[28:31] unused
RMS levels are not given directly. Instead, we are given a 64-bit number containing the mean of the squares of the peak levels shifted left by 4 (as above), multiplied by 2 so that the RMS levels of a sine wave matches the peak levels.
Sub ID 3 is used by the host to enable or disable loopback mode for output channels. The payload contains a single 32-bit integer with the following format:
[0:6] output channel
[7] loopback enabled
[8:31] unused
Sub ID 4 is used by the host to enable or disable EQ+D in recordings. The payload is a single 32-bit integer with the following format:
[0] eq+d enabled
[1:31] unused
In USB-mode, registers are set by the host through bulk endpoint 12, and the device notifies the host of updates through bulk endpoint 13. In either case, the bulk data consists of a sequence of 32-bit integers.
Unlike CC-mode, clock and hardware settings are set through control requests rather than writing to a bulk endpoint.
bRequest=0x4010 wIndex=0x5cf wValue=
[0:3] clock type 0=internal 2=word 4=spdif coax 6=aes 8=optical
[6] word clock single speed 0=off 1=on
[7] spdif format 0=consumer 1=professional
[8] eq+d for record 0=off 1=on
[10] optical output 0=adat 1=spdif
bRequest=0x4010 wIndex=0x30 wValue=
0x00 32000/12800
0x10 44100/88200/176400
0x20 48000/96000/192000
0x00 64000
Thanks to RME for providing information about registers 3081-3083!
0000 input settings
0000 mic 1
0000 mute 0=off, 1=on
0001 fxsend int*10
0002 stereo 0=off, 1=on
0003 record 0=off, 1=on
0004 ? all channels set to 0xa
0005 play channel 0=off, 1-60
0006 msproc 0=off, 1=on
0007 phase 0=off, 1=on
0008 gain int*10, inst/line=0.0-24.0, mic=0.0-75.0
0009 mic=48v 0=off, 1=on, line=level 0=+13dBu, 1=+19dBu
000a autoset 0=off, 1=on
000b n/a
000c lowcut 0=off, 1=on
000d freq int16, 20Hz-500Hz
000e dB/oct 0=6, 1=12, 2=18, 3=24
000f eq 0=off, 1=on
0010 band 1 type 0=peak, 1=shelf
0011 band 1 gain int*10, int16, -20.0dB-20.0dB
0012 band 1 freq int, 20Hz-20000Hz
0013 band 1 q int*10, 0.7-5.0
0014 band 2 gain int*10, int16, -20.0dB-20.0dB
0015 band 2 freq int, 20Hz-20000Hz
0016 band 2 q int*10, 0.7-5.0
0017 band 3 type 0=peak, 1=shelf, 2=hicut
0018 band 3 gain int*10, int16, -20.0dB-20.0dB
0019 band 3 freq int, 20Hz-20000Hz
001a band 3 q int*10, 0.7-5.0
001b dynamics 0=off, 1=on
001c gain gain*10, int16, -30.0dB-30.0dB
001d attack int, 0ms-200ms
001e release int, 100ms-999ms
001f compthres int*10, -60.0dB-0.0dB
0020 compratio int*10, 1.0-10.0
0021 expthres int*10, -99.0dB--20.0dB
0022 expratio int*10, 1.0-10.0
0023 autolevel 0=off, 1=on
0024 maxgain int*10, 0.0dB-18.0dB
0025 headroom int*10, 3dB-12dB
0026 risetime int*10, 0.1s-9.9s
0040 mic 2
...
0080 inst 3
...
0088 gain int*10, 0.0dB-24.0dB
0089 level 0=+13dBu, 1=+19dBu
008b hi-z 0=off, 1=on
...
00c0 inst 4
...
0100 line 5
...
010b n/a
...
0140 line 6
0180 line 7
01c0 line 8
0200 spdif 9
...
0208 n/a
0209 n/a
...
0240 spdif 10
0280 aes 11
02c0 aes 12
0300 adat 13
0340 adat 14
0380 adat 15
03c0 adat 16
0400 adat 17
0440 adat 18
0480 adat 19
04c0 adat 20
0500 output settings
0500 line 1
0500 volume int*10, -650=-inf, -65.0dB-6.0dB, step=0.5dB
0501 balance -100-100 (L100-0-R100)
0502 mute 0=off, 1=on
0503 fxreturn -650=-inf, int*10, -64.5dB-0.0dB, step=0.5dB
0504 stereo 0=off, 1=on, extra data?
0505 record 0=off, 1=on
0506 ? all channels set to 0xa
0507 playchannel 0=off, 1-60
0508 phase 0=off, 1=on, extra data
0509 ref level 0=+4dBu, 1=+13dBu, 2=+19dBu
050a crossfeed int, 0=off, 1-5
050b volume cal. int*100, -24.0dB-3.0dB
050c lowcut 0=off, 1=on
050d freq int, 20Hz-500Hz (step?)
050e dB/oct 0=6, 1=12, 2=18, 3=24
050f eq 0=off, 1=on
0510 band1type 0=peak, 1=shelf
0511 band1gain int*10, -20.0dB-20.0dB
0512 band1freq int, 20Hz-20000Hz
0513 band1q int*10, 0.7-5.0
0514 band2gain int*10, -20.0dB-20.0dB
0515 band2freq int, 20Hz-20000Hz
0516 band2q int*10, 0.7-5.0
0517 band3type 0=peak, 1=shelf, 2=hicut
0518 band3gain int*10, -20.0dB-20.0dB
0519 band3freq int, 20Hz-20000Hz
051a band3q int*10, 0.7-5.0
051b dynamics 0=off, 1=on
051c gain int*10, -30.0dB-30.0dB
051d attack int, 0ms-200ms
051e release int, 100ms-999ms
051f compthres int*10, -60.0dB-0.0dB
0520 compratio int*10, 1.0-10.0
0521 expthres int*10, -99.0dB--20.0dB
0522 expratio int*10, 1.0-10.0
0523 autolevel 0=off, 1=onn
0524 maxgain int*10, 0.0dB-18.0dB
0525 headroom int*10, 3dB-12dB
0526 risetime int*10, 0.1s-9.9s
0540 line 2
...
0580 line 3
05c0 line 4
0600 line 5
0640 line 6
0680 phones 7
...
0689 ref level 0=+4dBu, 1=+19dBu
...
06c0 phones 8
0700 spdif 9
...
0709 n/a
...
0740 spdif 10
0780 aes 11
07c0 aes 12
0800 adat 13
0840 adat 14
0880 adat 15
08c0 adat 16
0900 adat 17
0940 adat 18
0980 adat 19
09c0 adat 20
2000 mixer label
2000 mix 1
2000 input 1 vol/pan signed 15-bit integer, if high bit 0, vol*10 or -300 if -inf, if high bit 1, pan -100-100
2001 input 2 vol/pan
...
2013 input 20 vol/pan
2040 mix 2
...
24c0 mix 20
2fc0 ? sent when register dump finished
3000 reverb 0=off, 1=on
3001 type int, 0=Small Room, 1=Medium Room, 2=Large Room, 3=Walls,
4=Shorty, 5=Attack, 6=Swagger, 7=Old School,
8=Echoistic, 9=8plus9, 10=Grand Wide, 11=Thicker,
12=Envelope, 13=Gated, 14=Space
3002 predelay int, 0ms-999ms
3003 lowcut int, 20Hz-500Hz
3004 room scale int*100, 0.50-3.00 (rooms only)
3005 attack time int, 5ms-400ms (envelope only)
3006 hold time int, 5ms-400ms (envelope and gated only)
3007 release time int, 5ms-500ms (envelope and gated only)
3008 high cut int, 2kHz-20kHz
3009 reverb time int*10, 0.1s-4.9s (space only)
300a damp int, 2kHz-20kHz (space only)
300b smooth int, 0-100%
300c volume int*10, -65.0dB-6.0dB, -650=-inf
300d width int*100, 0.00-1.00
3014 echo 0=off, 1=on
3015 echo type 0=Stereo Echo, 1=Stereo Cross, 2=Pong Echo
3016 delay time int*1000, 0.000s-2.000s
3017 feedback int, 0-100%
3018 high cut 0=off, 1=16kHz, 2=12kHz, 3=8kHz, 4=4kHz, 5=2kHz
3019 volume int*10, -65.0dB-6.0dB, -650=-inf
301a stereo width int*100, 0.00-1.00
3050 control room
3050 main out 0=1/2, 1=3/4, ..., 9=19/20
3051 main mono 0=off, 1=on
3052 phones source?
3053 mute enable 0=off, 1=on
3054 dim reduction int*10 -65.0dB-0.0dB
3055 dim 0=off, 1=on
3056 recall volume int*10 -65.0dB-0.0dB
3060 clock [CC-only]
3064 clock source 0=internal 1=word clock 2=spdif 3=aes 4=optical
3065 sample rate 0=32000 1=44100 2=48000 3=64000 4=88200 5=96000 6=128000 7=176400 8=192000 [R]
3066 word clock out 0=off 1=on
3067 word clock single speed 0=off 1=on
3068 word clock termination 0=off 1=on
3070 hardware
3078 optical out 0=adat 1=spdif
3079 spdif format 0=consumer 1=professional
307a cc mode 0=off 1=on (only changes ui)
307b cc mix 0=totalmix 1=6ch+phones 2=8ch 3=20ch
307c standalone midi 0=off 1=on
307d standalone arc 0=volume 1=1s op 2=normal
307e lock keys 0=off 1=keys 2=all
307f remap keys 0=off 1=on
3080 dsp load [R]
[0:7] dsp load
[8:15] dsp version
3081 dsp function available
[0] 1 low cut
[1] 2 low cut
[2] 1 eq
[3] 2 eq
[4] 1 dynamics
[5] 2 dynamics
[6] 1 autolevel
[7] 2 autolevel
[8] 1 record
[9] 2 record
[10:15] unused
3082 dsp function overload
[0] play 1=ok 0=overload
[1] low cut 1=ok 0=overload
[2] eq 1=ok 0=overload
[3] dynamics 1=ok 0=overload
[4] autolevel 1=ok 0=overload
[5] record 1=ok 0=overload
[6] delay 1=ok 0=overload
[7] room eq 1=ok 0=overload
[8:15] channel number
3083 arc encoder delta
[0:13] encoder delta
[14:15]
3180 compression levels [R]
3180 input 1/2
[0:7]
[8:15]
3181 input 3/4
3182 input 5/6
3183 input 7/8
3184 input 9/10
3185 input 11/12
3186 input 13/14
3187 input 15/16
3188 input 17/18
3189 input 19/20
318a output 1/2
318b output 3/4
318c output 5/6
318d output 7/8
318e output 9/10
318f output 11/12
3190 output 13/14
3191 output 15/16
3192 output 17/18
3193 output 19/20
3200 channel names [RW]
3200 input 1 name (null terminated, max 11 chars)
3200 [0:1]
3201 [2:3]
3202 [4:5]
3203 [6:7]
3204 [8:9]
3205 [10:11]
3208 input 2 name
3210 input 3 name
...
3290 input 19 name
3298 input 20 name
32a0 output 1 name
32a8 output 2 name
32b0 output 3 name
...
3338 output 20 name
3380 autolevels [R]
3380 input 1/2
[0:7]
[8:15]
3381 input 3/4
3382 input 5/6
3383 input 7/8
3384 input 9/10
3385 input 11/12
3386 input 13/14
3387 input 15/16
3388 input 17/18
3389 input 19/20
338a output 1/2
338b output 3/4
338c output 5/6
338d output 7/8
338e output 9/10
338f output 11/12
3390 output 13/14
3391 output 15/16
3392 output 17/18
3393 output 19/20
3580 durec status [R]
3580
[0:3] 0=no media 2=initializing 3=deleting? 5=stopped 6=recording a=playing
[4:7] ?
[8:15] progress bar, 00=0% 41=100%
3581 playback/record position
3582 ?
3583 usb load/errors
[0:7] errors
[8:16] load %
3584 total space GB*16
3585 free space GB*16
3586 total tracks
3587 selected track
3588 next track/play mode
[0:11] next track, fff=none
[12:15] play mode 0=single 1=UFX single 2=continuous 3=single next 4=repeat single 5=repeat all
3589 remaining record time
358a track number, 0xffff=name of last played track and pending record tracks/sample rate
358b filename[0:1]
358c filename[2:3]
358d filename[4:5]
358e filename[6:7]
358f [0:7]=sample rate enum [8:15]=channels
3590 track length
35d0 room eq
35d0 output 1
35d0 delay int*100, 0.00ms-42.5ms
35d1 enable 0=off 1=on
35d2 band 1 type 0=peak 1=shelf 2=high pass 3=low pass
35d3 band 1 gain int*10, -20.0dB-20.0dB
35d4 band 1 freq int, 20Hz-20000Hz
35d5 band 1 q int*10, 0.4-9.9
35d6 band 2 gain int*10, -20.0dB-20.0dB
35d7 band 2 freq int, 20Hz-20000Hz
35d8 band 2 q int*10, 0.4-9.9
35d9 band 3 gain int*10, -20.0dB-20.0dB
35da band 3 freq int, 20Hz-20000Hz
35db band 3 q int*10, 0.4-9.9
35dc band 4 gain int*10, -20.0dB-20.0dB
35dd band 4 freq int, 20Hz-20000Hz
35de band 4 q int*10, 0.4-9.9
35df band 5 gain int*10, -20.0dB-20.0dB
35e0 band 5 freq int, 20Hz-20000Hz
35e1 band 5 q int*10, 0.4-9.9
35e2 band 6 gain int*10, -20.0dB-20.0dB
35e3 band 6 freq int, 20Hz-20000Hz
35e4 band 6 q int*10, 0.4-9.9
35e5 band 7 gain int*10, -20.0dB-20.0dB
35e6 band 7 freq int, 20Hz-20000Hz
35e7 band 7 q int*10, 0.4-9.9
35e8 band 8 type 0=peak 1=shelf 2=low pass 3=high pass
35e9 band 8 gain int*10, -20.0dB-20.0dB
35ea band 8 freq int, 20Hz-20000Hz
35eb band 8 q int*10, 0.4-9.9
35ec band 9 type 0=peak 1=shelf 2=low pass 3=high pass
35ed band 9 gain int*10, -20.0dB-20.0dB
35ee band 9 freq int, 20Hz-20000Hz
35ef band 9 q int*10, 0.4-9.9
35f0 output 2
...
3610 output 3
3630 output 4
3650 output 5
3670 output 6
3690 output 7
36b0 output 8
36d0 output 9
36f0 output 10
3710 output 11
3730 output 12
3750 output 13
3770 output 14
3790 output 15
37b0 output 16
37d0 output 17
37f0 output 18
3810 output 19
3830 output 20
3dff [USB] written with cycling values 0x0000-0x000f, roughly 5 times a second
3e00 cue 0xffff=no cue, [0:7]=cue to, [8:15]=cue from [W] R?
3e01 ?
3e02 control room status [W]
[0]=?
[8]=main mono
[11]=external input
[12]=talkback
[13]=speaker B
[14]=dim enabled
[15]=?
3e03 ?
3e04 0x67cd trigger register dump [W]
3e05 ?
3e06 store state 0x0910=slot 1 0x0911=slot 2 0x0912=slot 3 0x0913=slot 4 0x0914=slot 5 0x0915=slot 6 [W]
3e07 ?
3e08 time [0:7]=minute, [8:15]=hour [W]
3e09 date [0:4]=day, [5:8]=month, [9:13]=year [W]
3e9a durec [W]
3e9a play control 0x8120=stop record, 0x8121=stop, 0x8122=record, 0x8123=play/pause
3e9b delete int, index with high bit set
3e9c track select int
3e9d seek int, seconds
3e9e track next/prev 0=previous, 1=next
3e9f next track 0xffff=stop, 0x8000=track 1, 0x8001=track 2, ...
3ea0 play mode 0x8000=single, 0x8001=UFX single, 0x8002=continuous, 0x8003=single next, 0x8004=repeat single, 0x8005=repeat all
3f00 [CC] written with cycling values 0x0000-0x000f, roughly (29.4, 24.3 idle) times a second [W]
4000 mixer [W]
4000 mix 1
4000 inputs
4000 input 1 volume
4001 input 2 volume
4002 input 3 volume
4003 input 4 volume
...
4013 input 20 volume
4020 playback
4020 playback 1 volume
...
4033 playback 20 volume
4040 mix 2
4040 inputs
4060 playback
4080 mix 3
4080 inputs
40a0 playback
40c0 mix 4
4100 mix 5
4140 mix 6
4180 mix 7
41c0 mix 8
44c0 mix 20
44c0 inputs
44c0 input 1 volume
...
44e0 playback
44e0 playback 1 volume
...
44f3 playback 20 volume
47a0 playback fxsend left
47a0 playback 1
47a1 playback 2
...
47b3 playback 20
47e0 playback fxsend right
47e0 playback 1
47e1 playback 2
...
47f3 playback 20
Value format
[0:14] signed 15-bit integer, phase-inverted if negative (only on playback channels and playback fxsend)
[15] full scale reference, if set, 0x1000, otherwise 0x8000
Decibel to register value
L = 10^(dB/20)
value = (L * 0x1000) | 0x8000 // if L > 0.5
L * 0x8000 // otherwise
Register value to decibel
dB = 20*log10((value & 0x7fff) / 0x1000) // if value & 0x8000
20*log10(value / 0x8000) // otherwise
Given a peak level L = 10^(dB/20), pan p from -100 (left) to
100 (right), and stereo width w from -1.0 to 1.0, output levels,
decibels and pan values are calculated as follows:
The pan law is contant power with sin/cos taper and -3 dB center.
θ = (p + 100) * π / 400
Lₗ = cos(θ) * L
Lᵣ = sin(θ) * L
dB = 20 * log10(L)
pan = p
Lₗₗ = (100 - max(p, 0)) * (1 + w) / 200 * L
Lₗᵣ = (100 + min(p, 0)) * (1 - w) / 200 * L
Lᵣₗ = (100 - max(p, 0)) * (1 - w) / 200 * L
Lᵣᵣ = (100 + min(p, 0)) * (1 + w) / 200 * L
Lₗ² = Lₗₗ² + Lₗᵣ²
Lᵣ² = Lᵣₗ² + Lᵣᵣ²
dBₗ = 10 * log10(Lₗ²)
panₗ = acos(2 * Lₗₗ² / Lₗ² - 1) * 200 / π - 100
dBᵣ = 10 * log10(Lᵣ²)
panᵣ = acos(2 * Lᵣₗ² / Lᵣ² - 1) * 200 / π - 100
Lₗ = (100 - max(p, 0)) / 200 * L
Lᵣ = (100 + min(p, 0)) / 200 * L
dBₗ = 20 * log10(Lₗ)
panₗ = 0
dBᵣ = 20 * log10(Lᵣ)
panᵣ = 0
0 32000 [USB-only]
1 44100
2 48000
3 64000 [USB-only]
4 88200
5 96000
6 128000 [USB-only]
7 176400
8 192000
Thanks to RME for providing information about the low cut filter!
The low cut filter with adjustable slope is the product of a sequence
of first-order elements, each with its pole scaled by a correction
factor
To derive the correction factors
Plugging in