OSP (Open System Protocol)
Bus RGB · ams OSRAM · osp
- Channels
- RGB
- Bits / channel
- —
- Supply
- 4.5–5.5 V
- PWM
- —
- Backup data
- no
- Packages
- 1
The automotive-interior addressable LED. Where a WS2812 is a fire-and-forget pulse stream, OSP is a bidirectional addressed bus: the host can read each LED’s measured colour data and temperature back and run its own colour correction. Licence- and royalty-free according to ams OSRAM. Included because it is what the car industry actually fits; it is not a NeoPixel replacement and cannot be driven by 800 kHz bit-banging.
Refresh & flicker
Channel depth, PWM frequency and the telegram format are in the separate “Open System Protocol” application note, which this catalogue does not hold, so they are null. Daisy chains of up to 1000 devices are quoted on the ams OSRAM product page and in trade press.
Timing
| Source | T0H | T0L | T1H | T1L | Period | Rate | Reset | ± |
|---|---|---|---|---|---|---|---|---|
| datasheet ↗ | — | — | — | — | — | — | — | — |
| Not a pulse-width code. Master to slave is Manchester coded at typically 2.4 Mbps (either differential over LVDS, or single-ended on SIOx_P with SIOx_N ignored); slave to master is NRZ with the clock on SIOx_N. The device has two SIO ports, each semi-duplex, each configurable to one of four modes (LVDS, MCU normal, MCU end-of-line, CAN FD transceiver mode) selected by pin pull-ups at power-on. Devices auto-address along the chain and can be read back (optical calibration data at 10 and 50 mA, temperature). The datasheet does not give the telegram layout. | ||||||||
Library support
Parts using this protocol
Dating evidence
Evidence, not a release date. A library commit proves the part existed by that date and says nothing about how long before.
- 2025-04-30 datasheet revision ams OSRAM KRTBI D2LM31.31 datasheet, version 1.2 ↗ day