IBM 6400 Series, Maintenance Information Manual

Page: 149 / 422

CMX Controller Board Handshake Sequences
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Check Security PAL and NVRAM — The chip select for NVRAM comes
from the security PAL. If the PAL is not installed, NVRAM cannot be
accessed, so the PAL is tested before NVRAM. If the security PAL is not
detected, boot codes displays “ERROR: SECURITY PAL NOT
DETECTED”. If a security PAL is detected, boot code checks for the
presence of NVRAM. If NVRAM is not found, boot code displays
“ERROR: NVRAM FAILURE”.
•
Test for Powerup File — Boot code checks for a DC executable file
called powerup.sbr. If found, it executes the file, then returns to boot
routines. If the file is not found, boot routines are resumed. If any key was
held down during power up, boot code does not look for the powerup file
and continues the boot sequence.
•
Automatic EC Update — Boot code checks whether the automatic EC
update feature is enabled by the DC program. If so, it looks for a copy of
the EC program in the Flash File System. If it has a copy, it compares the
program in EC flash to the program in the Flash File System, and updates
the EC program if they are different. If the automatic EC update was not
enabled, or if any key was held down during power up, automatic EC
update is skipped and the boot sequence continues normally.
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Debug SIMM — The debug SIMM contains fast static RAM that
automatically replaces the flash memory. Boot code checks for the debug
SIMM and, if found, copies the contents of flash memory into the SIMM,
then remaps the address of the SIMM to the location of flash. This allows
breakpoints and single–stepping from the MTOS** debugger. When the
debug SIMM is found, boot code displays “DEBUG SIMM ACTIVATED”
on the panel and out the debug port.
•
Verify DC Program — Boot code calculates a checksum at every power
up to verify that the program has not been corrupted. If the checksum
does not match, boot code displays “ERROR: DC PROGRAM NOT
VALID”.
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Check Security — The security check verifies that security PAL supports
the software that is loaded in flash memory. If the PAL does not support
the software, boot code displays “SECURITY CODE VIOLATION”.
•
Check Required DRAM — Boot code checks whether the amount of
DRAM required to run the DC program is larger than the amount of
DRAM in the printer. If so, it displays the message “ERROR: PROGRAM
NEEDS MORE DRAM”.
•
Tell EC Processor to Finish Booting — Boot code informs the EC
processor that everything is okay and can finish booting up.
•
Diagnostics Passed — If all tests pass, boot code displays
“P05 DIAGNOSTIC TEST PASSED”. At this point, the ribbon motors
engage. Boot code then jumps to the start address of the DC software.
•
Display DC Program Information — Boot code sends the following
information out the debug port: the compile time, date, and the address it
will jump to to start the DC program.
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Waiting Ethernet — If boot code earlier detected an Ethernet adapter, it
places the message “WAITING FOR THE ETHERNET ADAPTER” on the
LCD so the user will not think the printer has crashed.