Oki OF5600, Руководство по обслуживанию

Страница: 306 / 448

Board Descriptions A - 22 OF 5300/5600 Serv Man, P/N 59278301
A3.2.3 M17 Circuit Diagram
1. Block diagram
The circuit diagram consists of Flash memory, Mask ROM, IC3 (Real time clock IC) and
Back up battery circuit.
Fig. A3.2.3 shows the block diagram of Flash memory, Mask ROM and Real time clock.
2. Function
1) Flash memory (FLS)
Flash memory (electrically erasable and programmable device) is used for the
main software program which is stored in EP-ROM of the current OKIFAX. Other
than the function of EP-ROM, Flash memory is also used for the user data area
instead of SRAM chips.
•
512 KByte Flash memory x 1 (FLS)
Used for work area, report recording etc.
2) Back-up battery circuit
•
Non-rechargeable lithium for RTC-IC (real-time clock IC)
3) Real-time clock IC (IC3)
IC3 is a real-time clock IC used as a timepiece to display the data and time in year,
month, day, hour, minute, and second units. Its input/output signals are the 4-bit
data bus (AD00 - AD03), 4-bit address bus (A01 - A04) and the control signals
PRDY0, RTCCS, MDMRD-N and RTCWR-N which perform a CPU-controlled read
operation (M/D/Y H:M, Data read) and write operation (M/D/Y H:M, Data setting).
4) MASK
• 512 KByte Flash memory or Mask ROM x 1 (MASK)
Used for program storage
Block Diagram of FLS, MASK and Real Time Clock (Figure A3.2.3)
MASK
IC3
A0 to A18
RMCS1-N/
RMCS0-N
MDRD-N/
MDWR-N
+24V
F12VON
RP/VPP
circuit
AD0 to AD15
AD0 to
AD3
A0 to A3
FLS
Back-up
battery
circuit
X2
32.768KHz
Rev. 2