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Monitor: Monitor Recovery and Updates
PmPPC7448 User’s Manual 10006757-02
11-4
POST Diagnostic Results
The PmPPC7448 Power-On Self-Test (POST) diagnostic results are stored as a 32-bit value
in I
2
C NVRAM at the offset 0x1DD8-0x1DDB. Each bit indicates the results of a specific test,
therefore this field can store the results of up to 32 diagnostic tests.
Table 11-1 assigns the
bits to specific tests.
Table 11-1: POST Diagnostic Results
Monitor SDRAM Usage
U-Boot locates its stack, uninitialized data, and code in the top one megabyte of SDRAM.
The exact address varies with the amount of installed memory. U-Boot uses the area from
0x00000000 to 0x00004000 in SDRAM for the MPC7448 exception vector table and U-Boot
internal use.
Caution: Any writes to these areas can cause unpredictable operation of the monitor.
MONITOR RECOVERY AND UPDATES
This section describes how to recover and/or update the monitor, given one or more of the
following conditions:
• If there is no console output, the monitor may be corrupted and need recovering
(“Recovering the Monitor” on page 11-4).
• If the monitor still functions, but is not operating properly, then you may need to reset
the environment variables (“Resetting Environment Variables” on page 11-7).
• If you are having Ethernet problems in the monitor, you may need to set the serial
number, since the MAC address is calculated from the serial number variable.
Recovering the Monitor
First, make sure that a monitor ROM device is installed in the PLCC socket of the DMC mod-
ule and the DMC module is installed on the PmPPC7448. Then, place a jumper on JP2,
across pins 3 and 4 on the DMC.
Bit: Diagnostic Test: Value:
0SDRAM
0 Passed the test
1 Failure detected
1Flash
2I
2
C
3 Reserved
4 Reserved
5 No EREADY
6 through 31 Reserved
!