Artesyn BajaPPC-750, User Manual

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Boot Commands 10-15
0002M621-15
bootbus uses the “LoadAddress” field from the nonvolatile memory definitions
group ‘BootParams’ (see Table 10-3) as the base address of a shared memory com-
munications structure, described below:
struct BusComStruct
{
unsigned long MagicLoc;
unsigned long CallAddress;
};
The structure consists of two unsigned long locations. The first is used for syn-
chronization, and the second is the entry address of the application.
The sequence of events used for loading an application is described below:
1. The host board waits for the target (this board) to write the value 0x496d4f6b
(character string “ImOk”) to “MagicLoc” to show that the target is initialized
and waiting for a download.
2. The host board downloads the application to the target board, writes the start
address to “CallAddress,” and then writes 0x596f4f6b (character string
“YoOk”) to “MagicLoc” to show that the application is ready for the target.
3. Target writes value 0x42796521 (character string “Bye!”) to “MagicLoc” to
show that the application was found. The target then calls the application at
“CallAddress.”
When the application is called, four parameters are passed to the application
from the nonvolatile memory boot configuration section. The parameters are
seen by the application as shown below:
Application(unsigned char Device,
unsigned char Number,
unsigned long RomSize,
unsigned long RomBase)
These parameters allow multiple boards using the same facility to receive
configuration information from the monitor.
Also refer to the function BootUp in Section 10.15.2.
10.4.2 booteprom
booteprom
is an autoboot device that allows you to boot an application pro-
gram from EPROM. It starts execution of the application at “RomBase,” read from
the non-volatile memory group ‘BootParams.’
DEFINITION
void BootEPROM(void)