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15–22 Chapter 15: Cyclone V Transceiver Native PHY IP Core
SDC Timing Constraints
Altera Transceiver PHY IP Core November 2012 Altera Corporation
User Guide
You can cut these paths in your Synopsys Design Constraints (.sdc) file by using
the
set_false_path
command as shown in Example 15–1.
You can use the
set_max_delay
constraint on a given path to create a constraint for
asynchronous signals that do not have a specific clock relationship but require a
maximum path delay. Example 15–2 illustrates this approach.
You can use the
set_false
path command only during Timequest timing analysis.
Example 15–3 illustrates this approach.
1 In in all of these examples, you must substitute you actual signal names for the signal
names shown.
Example 15–1. Using the set_false_path Constraint to Identify Asynchronous Inputs
set_false_path -through {*10gtxbursten*} -to [get_registers *10g_tx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10gtxdiagstatus*} -to [get_registers
*10g_tx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10gtxwordslip*} -to [get_registers *10g_tx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10gtxbitslip*} -to [get_registers *10g_tx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10grxbitslip*} -to [get_registers *10g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10grxclrbercount*} -to [get_registers
*10g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10grxclrerrblkcnt*} -to [get_registers
*10g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*10grxprbserrclr*} -to [get_registers
*10g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*8gbitslip*} -to [get_registers *8g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*8gbytordpld*} -to [get_registers *8g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*8gcmpfifoburst*} -to [get_registers *8g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*8gphfifoburstrx*} -to [get_registers
*8g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*8gsyncsmen*} -to [get_registers *8g*pcs*SYNC_DATA_REG*]
set_false_path -through {*8gwrdisablerx*} -to [get_registers *8g_rx_pcs*SYNC_DATA_REG*]
set_false_path -through {*rxpolarity*} -to [get_registers *SYNC_DATA_REG*]
set_false_path -through {*pldeidleinfersel*} -to [get_registers *SYNC_DATA_REG*]
Example 15–2. Using the max_delay Constraint to Identify Asynchronous Inputs
# Example: Apply 10ns max delay
set_max_delay -from *tx_from_fifo* -to *8g*pcs*SYNC_DATA_REG1 10
Example 15–3. Using the set_false TimeQuest Constraint to Identify Asynchronous Inputs
#if {$::TimeQuestInfo(nameofexecutable) eq "quartus_fit"} {
#} else {
#set_false_path -from [get_registers {*tx_from_fifo*}] -through {*txbursten*} -to
[get_registers *8g_*_pcs*SYNC_DATA_REG
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