P52
Hardware
3-5
3.3.6
100 MHz Base-T Ethernet
An WizNet™ Fast Ethernet Module can be installed to provide 100M Base-T network connectivity. This
Ethernet module has a hardware LSI TCP/IP stack. It implements TCP/IP, UDP, ICMP and ARP in
hardware, supporting internet protocol DLC and MAC. It has 16KB internal transmit and receiving buffer
which is mapped into host processor’s direct memory. The host can access the buffer via high speed DMA
transfers. The hardware Ethernet module releases internet connectivity and protocol processing from the
host processor. It supports 4 independent stack connections simultaneously at a 4Mbps protocol processing
speed. An RJ45 8-pin connector is on-board for connecting to 10/100 Base-T Ethernet network. A software
library is available for Ethernet connectivity.
3.3.7
Opto-couplers
There are 8 opto-couplers on the
P52
. These opto-couplers provide optical isolation and can be used for
digital inputs, relay contact monitor, or powerline monitor. These optos have a 3 micro-second ON time
and 5 micro-second OFF time. The on-board input pins have a 1k
Ω
pullup, so a low input signal will turn
the coupler ON. Opto-coupler intputs are routed to pins J4.1-8.
3.3.8
High-Voltage, High-Current Drivers
ULN2003 (U13 and U14) are high voltage, high current Darlington transistor arrays, consisting of 7 silicon
NPN Darlington pairs on a common monolithic substrate. All channels feature open-collector outputs for
sinking 350 mA at 50V, and integral protection diodes for driving inductive loads. Peak inrush currents of
up to 600 mA sinking are allowed. Outputs may be paralleled to achieve high-load capability, although
each driver has a maximum continuous collector current rating of 350 mA at 50V. The maximum power
dissipation allowed is 2.20 W per chip at 25 degrees C. The common substrate VS is routed to J4 pin 31.
All currents sinking in must return to the J4 pin 31, which should be shorted to GND. A heavy gage(20)
wire must be used to connect the GND terminal to an external common ground return. K connects to the
protection diodes in the ULN2003 chips and should be tied to highest voltage in the external load system.
K can be connected to an unregulated on board +12V.
ULN2003 is a sinking driver not sourcing driver.
Typical application wiring is shown below.
K
+12V
+12V
GND/SUB
GND/SUB
Power Supply
Solenoid
O1
ULN2003 TinyDrive
Figure 3.2 Drive inductive load with high voltage/current drivers.
