NetBootLoader
VMP2
Page 5 - 10
© 2002 PEP Modular Computers GmbH
ID 24855, Rev. 02
5.4.5.2
Programming an Application
The application image itself must be compiled and linked to run from the SDRAM base address
0x0 of the CPU. The image must contain executable PPC code at offset 0x100 which is the
usual case with ROM/Flash images.
Gaining access to the image for programming to FLASH depends on where it is located. The
NetBootLoader can access three different sources for images:
•
ftp server
•
Motorola S-Records
•
memory within the visible address range of the CPU board
The NetBootLoader uses a single data buffer for downloading an image from an ftp server or
an image as Motorola S-Records. These images must first be downloaded to the data buffer
prior to being programmed to FLASH. An image located within the visible address range of the
CPU board is directly accessible for programming.
To access an image located on an ftp server, the “get” command is used. To perform Motorola
S-Record acquisition, the “sl” (SLoad) command is used. Once the image is in the data buffer,
the FLASH is programmed using the “lf” (Load Flash) command. For an image within visible
memory, the “lf” (LoadFlash) command is used to program directly to FLASH.
5.4.5.3
ftp Server Access
To gain access to an application image file stored on an ftp server the Ethernet interface is
used. Images are downloaded to the data buffer using the ftp protocol. To use this interface the
Ethernet parameters must first be set and then the system must be restarted. During boot wait
the operator must gain control of the NetBootLoader and perform an ftp server login. After a
successful login, the operator then locates the image file required and downloads it to the data
buffer. As with any type of server session, the operator should logout when the session is fin-
ished.
5.4.5.4
Motorola S-Records
The NetBootLoader will also accept Motorola S-Records as an application image. The “sl”’
command accepts S1, S2 and S3 records. Operation is terminated by the appropriate S9, S8
or S7 record. Other types of records are ignored.
The checksum of every record except end records is checked. Bad records are rejected by the
NetBootLoader. The address range of every record is also checked. Records which fall outside
of the internal buffer are rejected.
The records must be 0-based. This means that it’s address must correspond to the address
where they will be loaded in the data buffer relative to its start. If necessary, the base address
can be modified with the -o option of the “sl” command.
Note ...
The commands “get” and “ls” use the same data buffer. Therefore if an “ls” com-
mand is issued after a “get” command the data buffer will be overwritten. If an “lf”
command follows the “ls” the NetBootLoader refuses to program the overwritten
data buffer to the FLASH.
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