Power-On Processing; Self-Diagnostic Test - Oki OKICOLOR 8 Maintenance Manual

2.12 Power-on Processing

2.12.1 Self-diagnostic test

(1) Initial test
The following checks are automatically performed when the OKICOLOR 8
page printer is powered on:
(a) ROM check
(b) RAM check
(c) EEPROM check
(d) Flash ROM check
(2) ROM check
(a) Checks ROM by comparing the sum of bits in the received data unit by the number of bits
in the transferred data unit.
(3) RAM check
(a) Checks RAM by writing a preset data pattern in RAM, reading the contents of RAM, and
comparing the data read from RAM by the data written in RAM. (Write-read test)
(b) Checks optional RAM if it is installed.
(c) Checks resident RAM by exclusively ORing high and low addresses (to prepare 16-bit
data units), writing a preset 16-bit data pattern in RAM, reading the contents of RAM, and
comparing the data read from RAM by the data written in RAM. Checks optional RAM
by writing and reading 32-bit fixed patterns ("5555h" and "aaaah") in optional RAM.
(4) EEPROM check
(a) Checks ID numbers stored in the fixed addresses of EEPROM.
(b) Checks the content of the menu area by control firmware and the engine area by engine
firmware.
(5) Flash ROM check
Checks Flash ROM by writing a present data pattern in Flash ROM, reading the contents of
Flash ROM, and comparing the data read from Flash ROM by the data written in Flash ROM.
(Write-read test).
(6) Option unit check
Checks whether the optional units (such as the second tray, PS SIMM, and so on) have been
installed before entering the operation mode.
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