This section applies to the WILC1000/3000 devices. When the WILC device is connected to the host using the SDIO bus, the host’s SDIO controller initializes, then interrogates the WILC device’s SDIO controller. The interrogation operation happens when the host is booting. If any SDIO device is powered ON after the host is booted, a rescan operation must be triggered to detect it.
The WILC device must be powered ON by default at start-up. For the WILC3000 Shield Board, there is an RC network for powering on. This can be done by mounting the resistor R312 with an approximate value of 120k in the location shown below on the ATWILC3000 Shield Board.Figure 5-1. SDIO Resistor on Shield Board
Tip: If the WILC module powers up automatically during the system boot, the rescan SDIO is not required because the ATWILC SDIO initialization and interrogation is performed during the system boot.
