Programmable Devices
CPLDs, FPGAs, SoC FPGAs, Configuration, and Transceivers
20705 Discussions

Constraint the path between CPU and FPGA

Altera_Forum
Honored Contributor II
1,056 Views

hi, all 

I want to constrain the path between CPU and FPGA. Timing diagram bellow is cutting from the datasheet of CPU 

current contraints: 

1. address latch enable input port, set_input delay for both rise and fall edge 

set_input_delay -rise -max -clock [get_clocks {CLK}] t11max [get_ports {ALE}] 

set_input_delay -rise -min -clock [get_clocks {CLK}] t11min [get_ports {ALE}] 

set_input_delay -add_delay -fall -max -clock [get_clocks {CLK}] t21max [get_ports {ALE}]  

set_input_delay -add_delay -fall -min -clock [get_clocks {CLK}] t21min [get_ports {ALE}]  

2. ship select input port 

set_input_delay -rise -max -clock [get_clocks {CLK}] t24max [get_ports {CPU_CS1 CPU_CS2}] 

set_input_delay -rise -min -clock [get_clocks {CLK}] t24min [get_ports {CPU_CS1 CPU_CS2}] 

set_input_delay -add_delay -fall -max -clock [get_clocks {CLK}] t14max [get_ports {CPU_CS1 CPU_CS2}]  

set_input_delay -add_delay -fall -min -clock [get_clocks {CLK}] t14min [get_ports {CPU_CS1 CPU_CS2}]  

 

3. read and write input port 

set_input_delay -rise -max -clock [get_clocks {CLK}] t20x [get_ports {CPU_WRH CPU_WRL}] 

set_input_delay -rise -min -clock [get_clocks {CLK}] t20n [get_ports {CPU_WRH CPU_WRL}] 

set_input_delay -add_delay -fall -max -clock [get_clocks {CLK}] t10max [get_ports {CPU_WRH CPU_WRL}]  

set_input_delay -add_delay -fall -min -clock [get_clocks {CLK}] t10min [get_ports {CPU_WRH CPU_WRL}]  

4. FPGA-TO-CPU data output port 

set_output_delay -clock {get_clocks {CLK}} -max t30 [get_ports {CPU_D}] -add_delay 

set_output_delay -clock {get_clocks {CLK}} -min t31 [get_ports {CPU_D}] -add_delay 

 

Are the constraints above correct? And I'm little confused how to contrain CPU-TO_FPGA input port? 

Thx
0 Kudos
0 Replies
Reply