JTAG SMT1 SMT2 compatibility

[diannaodanshi]

Hi,

Recently, the JTAG SMT1 on our Xilinx VC709 FPGA board is physically broken (and we are sure that the only broken part on this board is JTAG). However, it seems that JTAG SMT1 has retired and the only available one on your website is JTAG SMT2. So I want to know if we can replace the broken SMT1 with a new SMT2. In another word, is SMT2 compatible to our board?  

 

Thanks.

[JColvin]

Hello @diannaodanshi,

I checked with one of our senior engineers and the short answer is that it depends.

The JTAG power and ground pins are in the same location and the module is the same size, but there are 3 additional pads for GPIO signals on the SMT2. We didn't design the VC709 board, so we don't know how the landing pattern is for the SMT1, but if the landing pattern on the board is designed specifically for the SMT1 it may be possible to load the SMT2. However, since there are 3 additional pads on the right side of the module that aren't present on the SMT1, it's important to first check that there is no unmaksed copper on the host PCB in the area of those pads. If that is the case and there isn't any unmasked copper, then it's safe to load the SMT2.

You can view where the additional pads are on the SMT1 in it's reference manual here. We also have a 3D CAD model of the SMT2 available at the bottom of it's Resource Center.

Let us know if you have any further questions.

Thank you,
JColvin

[diannaodanshi]

2 hours ago, JColvin said:

Hello @diannaodanshi,

I checked with one of our senior engineers and the short answer is that it depends.

The JTAG power and ground pins are in the same location and the module is the same size, but there are 3 additional pads for GPIO signals on the SMT2. We didn't design the VC709 board, so we don't know how the landing pattern is for the SMT1, but if the landing pattern on the board is designed specifically for the SMT1 it may be possible to load the SMT2. However, since there are 3 additional pads on the right side of the module that aren't present on the SMT1, it's important to first check that there is no unmaksed copper on the host PCB in the area of those pads. If that is the case and there isn't any unmasked copper, then it's safe to load the SMT2.

You can view where the additional pads are on the SMT1 in it's reference manual here. We also have a 3D CAD model of the SMT2 available at the bottom of it's Resource Center.

Let us know if you have any further questions.

Thank you,
JColvin

Thanks so much, the information you provided is very useful!

 

I managed to find the PCB board design on Xilinx official website. and the landing pattern is like it is shown in the red square. I guess in this case, it's safe to replace the old one with SMT2, isn't it?

 

 

[JColvin]

Hi @diannaodanshi,

I'm not an expert at interpreting PCB design files, but as long as there isn't any exposed copper underneath, you should be good to go. If the SMT1 is physically broken on the board, it may be worth to unsolder it first and visually check underneath; if there is no copper there, then yes, you will be able to safely swap out the SMT1 for an SMT2.

Let us know if you have any more questions.

Thank you,
JColvin