cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
R_Vijayakumar
Newbie
Newbie
402 Views
Registered: ‎04-12-2021

Can we register PCOUT of DSP48E2 before connecting to next DSP48E2's PCIN?

Jump to solution

Hello,

I am experimenting with DSP48E2 to create 3 input adder(48bits). I wanted to achieve this function with one DSP48E2 slice.  I have configured  ALUMODE = "0000" and OPMODE = "110010011" => (A:B)+C+PCIN. 

In my design, 1st DSP48E2's PCOUT will be connected to PCIN of 2nd DSP48E2 slice via external register to match the clock latency of A,B and C ports. 

Can we register PCOUT of DSP48E2 before connecting to next DSP48E2's PCIN?

 

 

 

0 Kudos
1 Solution

Accepted Solutions
avrumw
Expert
Expert
343 Views
Registered: ‎01-23-2009

Can I connect a register output to PCIN

No. The only legal connection to the PCIN is the PCOUT of the DSP48 directly below it - there are no other legal connections. (Similarly the PCOUT can only connect to the PCIN of the DSP48 above it - there are no other connections).

You would have to exit on the P output, do what you want in the fabric and then enter back in on one of the non-cascade inputs (C, or A:B)

Avrum

View solution in original post

4 Replies
vkanchan
Xilinx Employee
Xilinx Employee
374 Views
Registered: ‎09-18-2018
HI , The 'P' register can be used to register the PCOUT. Refer Fig 2-1 in UG579
0 Kudos
R_Vijayakumar
Newbie
Newbie
366 Views
Registered: ‎04-12-2021


Thanks a lot vkanchan for your reply. It helps during the DSP cascading. I have one more question related to PCIN.

As I want to perform 3 input(48bits) adder using one DSP slice. Can I connect a register output to PCIN?

 

 

0 Kudos
avrumw
Expert
Expert
344 Views
Registered: ‎01-23-2009

Can I connect a register output to PCIN

No. The only legal connection to the PCIN is the PCOUT of the DSP48 directly below it - there are no other legal connections. (Similarly the PCOUT can only connect to the PCIN of the DSP48 above it - there are no other connections).

You would have to exit on the P output, do what you want in the fabric and then enter back in on one of the non-cascade inputs (C, or A:B)

Avrum

View solution in original post

R_Vijayakumar
Newbie
Newbie
304 Views
Registered: ‎04-12-2021

Thanks Avrumw for your clarification.

0 Kudos