Cermetek Microelectronics, Inc Page 17 of 42
Document NO. 607-00xx Revision A (12/13)
2.4. UART Frame Scheme
2.4.1. UART Free-Frame
CH232BGN supports the UART free-frame function. This function allows the module set frame breaks
based on the intervals between any two data bytes received through the serial port. If this interval time
exceeds the defined value (default 50ms), the CH232BGN interprets the interval as the end of a frame
and immediately transfers this frame to the WiFi port. If there is no pause in the data, the CH232BGN
buffers up to 4K Bytes of data before transferring the data as a frame to the WiFi port.
This Auto-Frame function is controlled by the commands AT+UARTF (Auto-Frame on/Off),
AT+UARTFT (Auto-Frame interval), and AT+UARTFL (Trigger length in Bytes).
Notes: The default frame interval is 50 milliseconds. The user can select a fast interval of 10
milliseconds; however, this increases the risk of fragmented data.
2.5. Address Binding
The CH232BGN module supports binding the Basic Service Set identification (BSSID) address of the
target network. According to the provisions of 802.11 protocol, different wireless networks can have a
same network name (i.e. SSID / ESSID), but must correspond to a unique BSSID address (i.e. MAC
address). Intruders could create a wireless network with the same SSID / ESSID and permit Stations
in the network to unknowingly connect to a fraudulent Access Point. Binding the BSSID address
prevents the Station from connecting to an intruder improving wireless network security.
2.6. Ethernet Interface Communication
CH232BGN module incluldes a 10/100M Ethernet interface. The Ethernet interface permits the user
to easily realize three types of communications (WiFi, Serial, and Ethernet). This allows the
CH232BGN to be configured as a Bridge or Router.
Notes: The CH232BGN consumes more power with Ethernet mode active. For that reason the default
configuration disables Ethernet. The command
“AT+FEPHY=on” activates Ethernet operation.
2.6.1. CH232BGN Ethernet Operation as Access Point
Figure 14: CH232BGN As Access Point
The CH232BGN module can serve as an access point to the Ethernet network. All devices in the
network must use the same network segment within their IP address.
