3.0 General Instructions:
1) Attach the JTAG programmer to the JTAG header, connecting TDO to TDO, TCK to TCK, TDI to TDI,
TMS to TMS, GND to GND, and 1.8V to VREF.
2) Since this JTAG chain has multiple devices the JTAG software usually needs to know about all the
devices in the chain to operate properly. Many times the software just needs to know the instruction
register length of each of the devices in the chain. Here is an example of such configuration from the
Xilinx XMD software (IR stands for instruction register):
Figure 3: Example JTAG configuration
3) Configure the JTAG operating frequency to 10Mhz or slower.
4) After you configure these settings you should be able to communicate with any device in the JTAG
chain. DO NOT USE SOFTWARE TO RECONFIGURE THE CPLD, you WILL CAUSE THE BOARD TO NO
LONGER FUNCTION PROPERLY. This should not be a concern unless you are intentionally trying to
program the CPLD.
