According to the AMBA-APB specification, it seems that PENABLE being HIGH while PSEL is LOW is a valid condition, but there are three assertions that report it as an issue:
//Property definition for sel signal valid value when enable is asserted
property amiq_apb_sel_validity_during_transfer_phases_p;
@(posedge enable) disable iff(!reset_n || !en_protocol_checks) (|sel);
endproperty
//Check that sel is HIGH when enable is asserted
AMIQ_APB_ILLEGAL_SEL_TRANSITION_TR_PHASES_ERR: assert property (amiq_apb_sel_validity_during_transfer_phases_p) else
`uvm_error("AMIQ_APB_ILLEGAL_SEL_TRANSITION_TR_PHASES_ERR", $sformatf("[%0t] AMIQ_APB_ILLEGAL_SEL_TRANSITION_TR_PHASES_ERR : sel must be stable during setup-access transitions.", $time))
//Property definition for enable valid value between transfers
property amiq_apb_enable_value_between_transfers_p;
@(posedge clk) disable iff(!reset_n || !en_protocol_checks)
!(|sel) |-> !enable;
endproperty
//Check that between two transfers enable is kept LOW
AMIQ_APB_ILLEGAL_ENABLE_VALUE_BETWEEN_TRANSFERS_ERR: assert property(amiq_apb_enable_value_between_transfers_p) else
`uvm_error("AMIQ_APB_ILLEGAL_ENABLE_VALUE_BETWEEN_TRANSFERS_ERR", $sformatf("[%0t] AMIQ_APB_ILLEGAL_ENABLE_VALUE_BETWEEN_TRANSFERS_ERR : enable must be LOW between two transfers.", $time))
//Property definition for enable stability during ready changes
property amiq_apb_enable_stability_during_ready_changes_p;
@(posedge clk) disable iff(!reset_n || !en_protocol_checks)
!ready and enable |=> enable;
endproperty
//Check that enable is stable during ready changes (when ready is asserted during a transfer, after a LOW period)
AMIQ_APB_ILLEGAL_ENABLE_TRANSITION_DURING_READY_CHANGES_ERR: assert property (amiq_apb_enable_stability_during_ready_changes_p) else
`uvm_error("AMIQ_APB_ILLEGAL_ENABLE_TRANSITION_DURING_READY_CHANGES_ERR", $sformatf("[%0t] AMIQ_APB_ILLEGAL_ENABLE_TRANSITION_DURING_READY_CHANGES_ERR : enable must be stable during ready changes.", $time))
Hi,
According to the AMBA-APB specification, it seems that PENABLE being HIGH while PSEL is LOW is a valid condition, but there are three assertions that report it as an issue:
Snapshot from spec:
