User`s manual

OnCell G3111/G3151/G3211/G3251 Series User’s Manual Software Installation/Configuration
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Fast Flush (only flushes the local buffer)
For some applications, the user’s program will use the Win32 “PurgeComm()” function before it
reads or writes data. After a program uses this PurgeComm() function, the OnCell driver continues
to query the OnCell’s firmware several times to make sure no data is queued in the OnCell
firmware buffer, rather than just flushing the local buffer. This design is used to satisfy some
special considerations. However, it may take more time (about several hundred milliseconds) than
a native COM1 due to the additional time spent communicating across the Ethernet. This is why
PurgeComm() works significantly faster with native COM ports on the PC than with mapped
COM ports on the OnCell G3111/G3151/G3211/G3251. In order to accommodate other
applications that require a faster response time, the new OnCell driver implements a new Fast
Flush option. By default, this function is enabled.
If you have disabled Fast Flush and find that COM ports mapped to the OnCell
G3111/G3151/G3211/G3251 perform markedly slower than when using a native COM port, try to
verify if “PurgeComm()” functions are used in your application. If so, try enabling the Fast Flush
function and see if there is a significant improvement in performance.
Auto IP Report: When OnCell G3111/G3151/G3211/G3251 products are used in a dynamic IP
environment, users must spend more time with IP management tasks. For example, if the OnCell
works as a server (RealCom mode, TCP Server mode, or UDP mode), then the host, which acts as
a client, must know the IP address of the server. If the DHCP server assigns a new IP address to
OnCell, the host must have some way of determining OnCell’s new IP address.
OnCell G3111/G3151/G3211/G3251 products help out by periodically reporting their IP address
to the IP location server, in case the IP has changed. The parameters shown below are used to
utilize the Auto IP report function. Once the OnCell Windows Driver Manager receives the Auto
IP Report message, it will change the IP address of the COM mapping entry for the OnCell
G3111/G3151/G3211/G3251 whose LAN MAC address is specified in the following MAC
address field.
9. The Serial Parameters tab in the following figure show the default settings when the OnCell
G3111/G3151/G3211/G3251 is powered on. However, the program can redefine the serial
parameters to different values after the program opens the port with Win32 API.