To get better antenna performance, the following two module locations are advised.
- Main board antenna area under module printed antenna should be clear or empty.
- No signals, GND or power traces can be routed in antenna area for each layers of the main board.
- Any mental lids, power traces or metal components should be placed far away from the antenna area on the main board.
- Keep GND plane as large as you can on main board.
WizFi250 provides some specific functions according to its firmware. Until now, there is a standard firmware and some customized firmware to specific customers available. It is possible to perform firmware updates.
WizFi250 decides its operating mode according to the input value of the BOOT signal. WizFi250 operates in boot mode when the BOOT input value is “LOW”, otherwise it operates in the standard run mode. WizFi250 communicates with a PC via UART in order to upload another firmware, so you have to connect UART1_RXD and UART1_TXD to the external interface for communicating with PC.
Two different schematics for that connection are listed below.
A simple circuit for updating firmware.
If your application MCU has UART communication with WizFi250, there is a possibility that the firmware update with an external PC will fail because of dual use of the one UART interface. In that case WIZnet cannot guarantee a completely successful update.
Therefore, please monitor the signal of BOOT with your MCU by a GPIO. Please stop the UART communication between your MCU and the WizFi250 when the BOOT input value is “LOW”. After that detection of a “LOW” BOOT signal you can succeed firmware update.
This circuit selects the UART communication using some extra hardware. If the BOOT SW is ON(GND), it is in BOOT Mode, and if the BOOT SW is OFF(3.3V) it is RUN Mode. The UART signal of the WizFi250 is connected to the firmware update UART (PC) when it becomes BOOT Mode, so firmware updates are made possible. The UART signal of the WizFi250 is only connected on your MCU if the BOOT signal is “High” and WizFi250 goes into the RUN Mode.