garvind25
Full Member level 3
Hi,
I am trying to build a CPLD system which I plan to program using a JTAG parallel 3 cable. In the CPLD board design what should I connect for JTAG cable VCC supply? Since my board has 3.3v and 5.0v, I can use either. But the documentation here (page 4) says :
“ The VCC supply level must match the I/O voltage level of the FPGA slave-serial configuration pins for best signal integrity.”
Since my VCCIO of the CPLD is fixed to 3.3v for both banks, should I choose 3.3v. I am asking this because I have been using my JTAG parallel 3 cable with an FPGA system (Spartan 3 based) which provides 5 v supply to the cable.
Also, should I connect the pins of male JTAG port of the CPLD board directly to the respective pins of CPLD IC or should I insert some resistance in-between the pins of the connector and IC? As per sheet 2 of link here, they have inserted 200 ohms in each signal line and have also given pull up resistors for TMS and TDI. Why so, and how are these resistances being calculated pls?
Thanks and Regards,
Arvind Gupta
I am trying to build a CPLD system which I plan to program using a JTAG parallel 3 cable. In the CPLD board design what should I connect for JTAG cable VCC supply? Since my board has 3.3v and 5.0v, I can use either. But the documentation here (page 4) says :
“ The VCC supply level must match the I/O voltage level of the FPGA slave-serial configuration pins for best signal integrity.”
Since my VCCIO of the CPLD is fixed to 3.3v for both banks, should I choose 3.3v. I am asking this because I have been using my JTAG parallel 3 cable with an FPGA system (Spartan 3 based) which provides 5 v supply to the cable.
Also, should I connect the pins of male JTAG port of the CPLD board directly to the respective pins of CPLD IC or should I insert some resistance in-between the pins of the connector and IC? As per sheet 2 of link here, they have inserted 200 ohms in each signal line and have also given pull up resistors for TMS and TDI. Why so, and how are these resistances being calculated pls?
Thanks and Regards,
Arvind Gupta