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Softload
Initiate Software Download: $Y=x
The $Y command initiates a softload into the alternate software
set. This command requires the softload password previously
set by the %P1 command. If the password does not match the
unit's stored password, the TA will return an ERROR message.
If the password matches, the TA begins by displaying the
softload method ID. This ID code must match the softload
method ID of the new software to be loaded.
After displaying the method ID, the TA begins erasing the
Flash memory devices for the alternate software set. If the
erasure is successful, the TA returns a READY message and
enters the YModem-G receive mode.
At this point, the TA is ready to accept a softload using the
YModem-G file transfer protocol. The TA sends the
YModem-G initiation character (G) until the DTE begins
sending YModem-G frames. If no frames are received within
two minutes, the TA will time out, send an ERROR message,
and return to the AT command mode.
The YModem-G transfer should send one file. During the
transfer, the TA may issue flow control requests to pace the
DTE's sending of data.
After the file has been transferred, the TA verifies that the file
has been received and programmed correctly. The TA then
sends a response code (OK or ERROR) to the DTE indicating
the success or failure of the entire softload.
If an error occurs during the transfer, or if the host fails to
respond to the YModem-G initiation requests, the TA returns
with an ERROR message. In this case, the alternate software
is marked as INVALID to prevent a swap attempt.
If an error occurs during the softload, the TA attempts to cancel
the YModem-G transfer by sending a series of ASCII CAN
characters (18 hex). It then returns to the AT command mode,
echoing any characters received from the DTE. Depending
upon when the host recognizes the cancel sequence, the host
may begin to display the echoed softload characters on its
screen. The DTE may also abort the transfer by sending 2 or
more CAN characters between YModem-G frames.
An example of a typical softload session is provided at the end
of this chapter.
UTA220/UTA220k
13-5
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