37.2.12.2 HDR Exit Pattern
Once an HDR mode is entered, the Controller uses the HDR Exit Pattern to leave it, always exiting back to SDR mode. The same HDR Exit Pattern is used to exit all HDR modes. The Target module can detect this pattern, following which it starts monitoring SDR traffic on the I3C bus again.
As an alternative to the HDR Exit Pattern, the HDR Restart Pattern allows multiple messages to be sent while in HDR mode without needing to exit to SDR mode in between messages. The Target module on this device cannot detect HDR Restart Pattern because it does not support any HDR modes.
The HDR Exit Pattern is shown in Figure 37-52 and Figure 37-53 and is defined as follows:
- SDA starts High, SCL starts Low
- SDA falls from High-to-Low four times while SCL remains Low for the whole time
- Each SDA transition is separated by the time interval of at least 32 ns
Important: If the HDR Exit Pattern is not preceded by a
Start or Restart, then the Bus Free BFREE bit will not set during the HDR Exit Pattern and the
following Stop condition will not be detected.