Per-channel Control command set
The US-224 includes a set of 4 channel-strip controls and LED's. Each channel-strip includes the following controls:
a.linear fader for gain control
b.Mute/Solo switch and LED
c.Record-enable LED
d.Select switch and LED
Three modifier switches affect the channel strip indicators:
a.A momentary NULL switch and LED (to aid the user in matching the fader sliders with the "virtual" value maintained by the application software). When the application receives a NULL button-down message, it compares its internal fader values with the most recently- received physical fader positions for the currently- active bank of eight channels, and sends out messages which light the REC and SELECT LED's to indicate the direction the user needs to move each of the faders to agree with the application's virtual fader levels. When the user releases NULL, the application sends REC and SELECT LED update messages which will cause them to revert to their "native" function (indicating record and channel-select status).
b.A REC (record) button which acts as a "shift" key, enabling the track select switches to affect the record-enable status of the corresponding track in the application software.
c.A MUTE/SOLO mode button, which toggles the function of the mute buttons and indicators, making them activate a SOLO function on their associated track.
US-224 to Host Commands:
1.FADER_POSITION: BF 4x vv x = [0..3], vv = [0..3F]
2.MUTE_SWITCH:
a.Button-down: BF 0x 7F
b.Button-up: BF 0x 0 x=[0..3]
3.SELECT_SWITCH:
a.Button-down: BF 2x 7F
b.Button-up: BF 2x 00 x=[0..3]
4.NULL_SWITCH
a.Button-down: BF 28 7F
b.Button-up: BF 28 00
5.REC_EN_SWITCH:
a.Button-down: BF 29 7F
b.Button-up: BF 29 00
6.SOLO_SWITCH:
a.Button-down: BF 2A 7F
b.Button-up: BF 2A 00
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