31
22 Sept 2016
v1.1
2.19 Fan Header – JP3
JP3, a three pin 0.85” pitch fan header has been placed to allow the customer to use a fan for
SOM cooling if needed. By default the header is connected to the VIN_SW which is +12V via
R161. If a 5V fan is desired, remove R161 and populate R162 with a 0402 zero ohm resistor.
Figure 19 – Fan Header connections
2.20 JTAG Configuration – J7
An auto switching JTAG interface port is provided on the PZCC-FMC-V2 through J7, a PC4
compliant connection. The port defaults to SOM JTAG operation unless an FMC board is
placed. Upon insertion of a FMC board, the interface will switch the FMC into the JTAG chain
via U3.
A Xilinx JTAG platform cable (HW-USB-II-G) or a Digilent JTAG HS2 or HS3 programming
cable should be used when programming via these ports. Diode D18 on the VREF pin is used
to prevent the JTAG cable from back feeding into the PZCC-FMC-V2 3.3V power supply.
Pullup resistors R191, R192, R193 are not populated by default as the FMC module should
have the pullup resistors in place. However, if the FMC module does not have the pullups, this
resistor pack can be placed.
Figure 20 – SOM & FMC JTAG Topology