Armadillo-9
hardware manual ver.1.02
6.4. Calendar Clock (Real Time Clock)
The calendar clock (Real Time Clock: S-3531A or compatible) is connected to the CPU (EP9315) by a 2-
wire serial line (GPIO). The CPU end accesses the RTC by controlling parallel port B (PB4, 5: EGPIO12,
EGPIO13) in a serial fashion.
During power-off, the RTC can maintain its operation for a certain period of time by the backup of the
polyacene capacitor (PAS). An external battery can be connected to maintain the content of the RTC while
power is turned off for an extended period of time.
3.3V
EP9315
EGPIO12
EGPIO13
3.3V
S-
353xxA
SDA
SCK
3.3V
BAT
(CON14)
Vcc
PAS
Figure 6-4 Connection of CPU (EP9315) and RTC
6.5. Power Circuit
The power circuit of the Armadillo-9 is shown in Figure 6-5. Be sure not to exceed each current capacity
limit when connecting external devices and designing the power supply.
Noise Filter
DC-DC
DC-DC
5V
IDE
PC/104
USB
1.8V
3.3V
Internal
Circuits
Internal
Circuits
CompactFlash
GPIO Connectors,
COM Connectors
Current
Limit
500mA
6A (max)
1.2A(max)
5V
600mA(max)
250mA(max)
Figure 6-5 Armadillo-9 Power Circuit
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