1.11 s11: When configured as a PLCA coordinator, the device does not stop transmitting beacons immediately upon entering sleep mode

Description

The device does not stop transmitting beacons immediately upon entering sleep mode when configured as a PLCA coordinator. The coordinator node, NODE_ID = 0, transmits a beacon at the start of each PLCA bus cycle. When sleep mode begins, the transmitter is not disabled until VDDA drops below its valid level. When configured to sleep on the inactivity timeout, the coordinator node will recognize the beacon as bus activity and wake itself back up.

End User Implications

The coordinator mode will not reliably remain in sleep mode when configured to sleep on an inactivity timeout, as it will interpret its own beacon as network activity. Continued presence of beacons will cause other devices on the mixing segment to detect signal activity, so any other devices that are configured to sleep on inactivity will not sleep.

Work Around

The coordinator node (NODE_ID = 0) must never be configured to sleep on inactivity timers. It must be put into sleep mode by its station controller. In addition, immediately before entering sleep, the coordinator must have PLCA disabled to stop the beacon.

  1. Clear the EN bit of the PLCA_CTRL0 to disable the beacon.
  2. Enter sleep mode and configure a non-zero delay by writing to the following bitfields of SLPCTL0:
    • Set SLPEN to 1.
    • Set WKINEN and MDIWKEN to configure desired wake source(s).
    • SLPCAL must be written as 0x0.
    • Set SLPINHDLY to 1 or greater.

Resolved with the release of Silicon Rev D0.