The display (Pi)

The Pi can drive an 800x480 display: HDMI with USB touch, or a DSI touchscreen on the Pi’s display connector. Connect it before power-on.

Display	Status
5” / 7” HDMI LCD with USB touch (800x480): HDMI to the Pi’s micro-HDMI 0 (next to the power socket), touch to a free USB-A port	hardware (a 5” HDMI LCD)
Official Raspberry Pi 7” Touch Display (v1, DSI)	expected, being confirmed
Compatible 7” DSI displays such as the OSOYOO 7” DSI V4.0	expected, being confirmed
Raspberry Pi Touch Display 2	not supported

With a DSI display and HDMI both connected, the Sidecar draws on the DSI display; dsi=0 in cmdline.txt keeps it on HDMI. Do not add ignore_lcd=1, disable_touchscreen=1 or a vc4-kms overlay to config.txt.

Boot screen

The Sidecar wordmark with a progress bar, drawn within a third of a second of the engine starting. The home screen follows a few seconds later.

The boot screen: the Sidecar | Expander wordmark over a green progress bar

Home

The display’s home screen with the touch test: tracks 1-8, status with REC and the core loads, the touch test, the project’s U1..U5 The home screen with the touch test hidden: a SIDECAR panel with the network, web page, link and recorder in its place

Screenshots: the 1021 display rendered off-device with mock data. The restyled display is hardware-tested.

The title bar, with Rytm connected (green) or Rytm not connected (red).
Tracks: the Sidecar’s voices 1-8 with their current machine (numbered by voice: 1 BD, 2 BT, 3 SD, 4 LT, 5 CH/OH, 6 MT/HT, 7 CY/CB, 8 RS/CP).
Project: the Rytm’s project and its U1..U5 machines as the Rytm shows them (!ROOM NAME, !MISS NAME etc. when it cannot play, with the reason; NAME... loading, --- empty).
Status: Overbridge blocks, underruns (red once nonzero), load bars for the render cores, and REC while recording.
Touch test: a tap button and a slider to check the touch panel. Once touch works, press Touch works – hide: a SIDECAR panel (network, web page, link, recorder) takes its place. The About page has a Show / Hide toggle to bring it back; the choice is stored as touchtest= in /.rytm/display.txt.

Settings

Settings, Sound page: MIDI notes, output, computer audio, FIFO target; per voice the machine and a test drone Settings, Send FX page: FX 1 in green, FX 2 in white, the 12 tracks’ send levels, Kill tails Settings, About page: web address, IP, link, build, screensaver, the touch test toggle and brightness

Screenshots: the 1021 display rendered off-device with mock data.

The Settings button (top right) opens the settings pages and becomes Home. Every control is at least 48 px high.

Page
Sound	MIDI notes, output (Main/Tracks), computer audio, the buffer target; per voice: machine and test drone
Send FX	both effects’ TYPE and the 12 send levels (read only: the Rytm’s kit owns them; FX 1 green, FX 2 white), and Kill tails
About	the web address, IP, network, the build, the screensaver, the touch test (show / hide) and brightness

The display, the web page and the console share one state: a change on one shows on all.

Screensaver and brightness

Screensaver: after 1 hour without a touch (default) the screen goes black. Choose Off, 15 min, 1 h or 4 h. Any touch wakes it; that touch only wakes the screen. Rytm activity does not keep it awake.
Brightness: 5 to 100 %. It dims the picture (the panel has no software backlight control); even the darkest setting stays readable, so you can always find the slider again.
Both are stored on the card (/.rytm/display.txt) and can be set from the web page too.

Touch

If touch is offset or mirrored, read the raw values from the touch readout and set touchscreen=minx,maxx,miny,maxy in cmdline.txt. Touch errors on the panel’s USB link are recovered automatically.

Cost

The display runs on the core that also handles USB, but the audio is interrupt-driven and does not wait for it. At rest an update takes about 0.3 ms. display=0 in cmdline.txt turns it off.