Technical information

Chapter 2: AT+i Commands Reference
May 31, 2008 AT+i Commands Reference Manual 2-123
+iCKSM - Checksum Mode
+iHIF - Host Interface
AT+i DF ~n Temporarily sets the IP protocol Don't Fragment bit to n for one
session. The permanent value will be restored after completing
the next session, both if the session was successful or not.
AT+iDF? Reports the current IP protocol Don't Fragment bit setting
followed by I/OK.
AT+iDF=? Returns the message "0-1" followed by I/OK.
Syntax: AT+iCKSM=<n>
Sets W24's checksum mode. With this mode enabled, W24
calculates the checksum of data it returns to host upon receiving
the AT+iSRCV command. At the same time, W24 expects the
host to append checksum to the data it sends with the AT+iSSND
command. W24 compares the checksum it calculates with the one
calculated by the host to verify that data was not corrupted during
transmission between host and W24.
Parameters: n=0 | 1
Command Options:
n=0 Checksum mode disabled.
n=1 Checksum mode enabled.
Default: n=0 (checksum mode disabled).
Result Code:
I/OK If n is either '0' or '1'.
I/ERROR Otherwise.
Syntax: AT+iHIF=n
Specifies the interface to be used for communication between the
host processor and W24 in subsequent sessions. This parameter
takes effect only after power-up.
Parameters:
n=0 Automatic host interface detection. In this mode, the first
character sent from the host over one of the supported interfaces
sets the host interface to be used throughout that session until the
next W24 power cycle.
If HIF is set to a fixed interface (n=1-5) and the MSEL signal is
pulled low for more than 5 seconds during runtime, W24 switches
to auto host interface detection mode (HIF=0).