Furuno NX-700B Service Manual page 80

U13
EEPROM
(32kx8bits)
Key scan
Source
KEY x 10
Key scan
Retrn
Key
Back light
CR1/4/9/
19/13/10
U8
ROM
SRAM
DRAM
CPU RAM
EEPROM
RESET n
U7
T/RxD 0
RS232C I/F
RxD 2
RS485 I/F
TxD 1
(ISO)
490 DEC IN
518 DEC IN
RCV TX0
RCV TX1
Beep SP
ALARM BZ
MOS RL
Fig. 5.3.3 Block Diagram: CPU block
Memory
ROM integrating U8
U10
U5
ROM integrating U8
U13
U10
Backup
SRAM
(512kB)
RESET n
U4
LCD
Controller
LCD
Back light
Contrast
D/A
U2
U28
U16/19
RS485 I/F
LS1
FDK
U17
Table 5.3.2 Memory contents
Memory description
Program storage
All received messages and setup menus,
work memory
Memory for display, work memory
CPU work memory
When a battery for the SRAM (U10) back up is
replaced, all the setup menus stored here are
transferred to the SRAM.
Setting data is updated every hour.
5-9
5.3 Block Description
U11
Reset BT1
BATT
U5
DRAM
(512kB)
LCD
Printer SD/RD
INS TD-A/B, RD-A/B
ALARM
NAVTESX
Receiver