Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

Constraint the path between CPU and FPGA

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
No RepliesBe the first to reply