Siemens SIMATIC PC RI25/45 Technical Description page 89

Functional Block
Figure 4-1 shows the basic block diagram of a SafeCard. The cross-hatched
Diagram blocks represent possible components of the individual PCs.
ISA D-Bus(0:7)
ISA address bus (0:23)
IOW, IOR, AEN
MEMW, MEMR, BALE
IRQ5, 10, 11, 12, 15
RESETDRV
CLK
Figure 4-1 Functional block diagram of a SafeCard
SIMATIC PC RI25/45, Technical Description
C79000-G7076-C808-01
ISA
Interface
IRQ
Logic
Address
decoder
Conf.
register
CS_RAM
LS_BUS(0:6)
LS_BUS(0:16)
LS_BUS(0:7)
Monitoring Module
Watchdog
Driver for
status display
7-Seg/LEDs
Signaling
relay
Ä Ä Ä
Temperature
Ä Ä Ä
reference
Ä Ä Ä
Ä Ä Ä
RESET logic
Ä Ä Ä
Ä Ä Ä
Fan power
supply
PWR_GOOD
generator
64 KB
SRAM
opt.
X14
Battery
optional
Connector X2
towards LEDs
and 7-Seg.
Relay
connector
X13
Temp.
sensor
via x2
Reset push
button via
x2
4 x 2-pin
connector
X6, 7, 8, 9
Connector
X4 towards
motherboard
4-3