AR# 1051: XNFPREP: Error 3526: Illegally inverted pin with XBLOX SYNC_RAM symbol
AR# 1051
XNFPREP: Error 3526: Illegally inverted pin with XBLOX SYNC_RAM symbol
説明
Keywords: xnfprep, error 3526, xblox, RAM
Urgency: Standard
General Description:
During compilation of a XC4000E design containing an XBLOX SYNC_RAM component, XNFPrep may give the following error:
XNFPREP: ERROR 3526: The pin 'D' on the symbol <symbol name> (type = RAMS, output signal = [signal name]) is illegally inverted. This pin in non-invertible.
This error is occurs while placing either an INVBUS symbol or INV symbol on the WR_CLK pin to clock the synchronous RAM on the falling edge. XBLOX pushes the inversion onto the device pin instead of leaving the inverter separate as it should.
ソリューション
Place an X (explicit) property on the net between the INV/INVBUS and the SYNC_RAM. This will prevent the inverter from being absorbed into the D pin of the synchronous RAM.