Device
and operation
CPC307
C P C 3 0 7 U s e r M a n u a l
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4.3.18 Module power supply voltage supervisor
When the +5V voltage is supplied, the ADM706T supervisor generates a module reset signal of
0.200 seconds duration (the
“Powergood” signal will be set by inactive level “0”), provided that the
supply voltage e3.08V. If the +5V voltage drops down to +4.45V during operation, a PFO#
(Power Fail Output) signal is generated by the ADM706T supervisor. This signal can be switched
to line 0 of GPIO1 port and/or to the IOCHK# (NMI) line of the ISA bus by setting the
corresponding jumpers on the XP25 connector pins. When the supply voltage drops down to +3.08
V, a hardware processor reset signal will be generated (the Powergood signal will be set by
inactive level "0") until the supply voltage returns to the level above +3.08 V.
See also paragraph
4.3.20 Configuration jumpers
and paragraph
4.3.19 GPIO Ports
.
The opto-isolated reset/interrupt signal (circuit Ext_RST_IRQ# in Figure 4.32) is described in more
detail in paragraph
4.3.7 Opto-isolated reset/interrupt
.
Figure 4.32. Diagram of the module's power supply voltage supervisor
4.3.19 GPIO ports
The Vortex86DX SoC chip has 3 input/output ports - GPIO (General Purpose Input Output), that
are accessible to the user through the internal registers of the chip. Each port represents 8 x I/O
lines, each of which can be configured as input or output by programming the registers of the
corresponding port.
The GPIO ports use two 8-bit registers per port - a data register and a direction register.
Each bit of the data register is matched to a corresponding circuit on the board: bit 0 corresponds
to port line 0 (GPIOx0), bit 7 corresponds to port line 7 (GPIOx7), etc.
Each bit of the direction register is matched to a corresponding circuit on the board: bit 0
corresponds to port line 0 (GPIOx0), bit 7 corresponds to port line 7 (GPIOx7), etc.
The GPIO0 port is fully routed to the XP14 connector.
The GPIO1 port is used to control the external watchdog, to enable/disable the soldered ATA Flash
disk controller.
The GPIO2 port is used to control COM1, COM2 ports, user LEDs and to read the state of SA1
switch.
