How to enable JTAG for BPI-R3


I want to use the JTAG in BPI-R3. According to, I connect the pin 19,21, 23, 24 and one GRD pin 25 to the JTAG tool. Do I need to connect other pins?Seems these pins are multi-purpose pins.We also need to set some other settings. @sinovoip, would you help? Thanks!