Samsung SF4500, Руководство по обслуживанию

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6-10 Samsung Electronics
6-1-2-10. RESET CIRCUIT
As for this product, there are 2 power resets of pri-
mary reset(/F-POR) and secondary reset(/POR) and
also reset by watchdog timer (/RSTO). Primary re s e t
is used to initialize flash memory when the system is
turned on, while secondary reset is used to initialize
the whole system by initializing MFP c o n t ro l l e r
(KS32C6200) after primary reset. Primary reset makes flash memory wait in
READ mode to fetch program
codes, and secondary reset makes the main
c o n t roller (KS32C6200) wake up and initialize
external peripherals to operate the system.
Fig.5-1-10 is Power Reset Timing Diagram.
• POWER MONITOR (U103: KIA7045F)
If +5V supplied to KIA7045F is so unstable as to
reach +4.65V - +4.35V (typically 4.5V), it will
recognize it as power failure. Then KIA7045F
output terminal becomes low (0V) and the voltage
is impressed to flash memory and KS32C6200, ru n-
ning RESET (LOW ACTIVE). Flash memory and
KS32C6200 are reset first. Thereafter modem, print
c o n t rol parts and SCANIP(Color Image Pro c e s s o r )
linked to /RSTOUT terminal of KS32C6200 are
reset as well. KIA7045F output
terminal of open drain stru c t u re is pulled up 5.1k
Ω
and put out.
Fig.6-1-10 POWER RESET TIMING DIAGRAM