IBM 6400 Maintenance Information Manual page 148

Chapter 5
The Power On Sequence
•
Display VX Registers — The boot code displays the values of the VX
registers out of the debug serial port.
•
Check for Pedestal — Boot code uses the operator panel to determine if
the printer is a pedestal or floor cabinet model. Boot code needs to know
the difference so the exhaust fan fault can be disabled on a pedestal
model. "FAN DISABLED" is printed out at the debug serial port of a
pedestal model.
•
Check for Download Mode — Boot code checks whether the Cancel
and Start keys were pressed at power up. If so, the printer enters
download mode. If not, the printer continues the boot routines.
•
Check for Diagnostics Mode — Boot code checks whether the Eject/
Restore and Stop keys were pressed at power up. If so, the printer
enters the Boot Diagnostics menu. If not, the printer continues the boot
routines.
•
Check for Remote Download Mode — Boot code checks if the user
remotely requested the printer to enter download mode. If so, the printer
enters download mode. If not, the printer continues boot routines.
•
Check for Flash Optimize — Boot code checks if the user requested the
flash file system to be optimized at power up. If so, flash memory is
optimized at this time. If not, the printer continues boot routines.
•
Check EC Program — The EC calculates a checksum of the program
stored in its flash memory. If there is problem with its program, the EC
puts the message "nopg" in the ECDC communications register. If the
boot code detects this message, it displays "ERROR: EC PROGRAM
NOT VALID" on the LCD. If the EC processor does not respond within
three seconds, the boot code sends "EC STOPPED AT STATE XXXX" to
the LCD, where XXXX is one of these states:
State
0000
0001
0002
0003
0004
0005
0006
0007
0008
0009
000A
148
Description
Power up
Enter checksum calculation
Enter copy download code from FLASH into shared DRAM
Enter programming FLASH mode
Erase EC FLASH
Program FLASH
Finish programming FLASH
Enter initialization of EC serial debug
Enter EC firmware task initializations
Enter power up coil diagnostic
Start running normal EC firmware