Service manual

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 5.1kΩ

and put out.

Fig.6-1-10 POWER RESET TIMING DIAGRAM