PIN - 2023.2 English

Vivado Design Suite Properties Reference Guide (UG912)

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2023.2 English


A pin is a point of logical connectivity on a primitive or hierarchical cell. A pin allows the contents of a cell to be abstracted away, and the logic simplified for ease-of-use. Pins can be scalar, containing a single connection, or can be defined as bus pins to group multiple signals together.

Related Objects

Figure 1. PIN Objects

A pin is attached to a cell and can be connected to pins on other cells by a net. The pins of cells are also related to the bel_pins of the bel object, or site_pins of a SITE that the cell is mapped to. Pins are associated with clocks as part of the clock domain, and are part of timing_paths when defined as the start point, end point, or through point of the path.

Pins can also be associated with drc_violations to allow you to more quickly locate and resolve design issues.


The PIN object includes a collection of properties that define the type of pin for clock and control pins. You can use these attributes to filter the list of pins by type when writing Tcl scripts, or working with PIN objects. The properties are listed in the following table.

Table 1. Properties for PIN Object
Property Name Clock Relationship Description Example
IS_CLEAR Asynchronous Forces block output(s) to a 0 state. CLR pin in the FDCE
IS_CLOCK Reference The pin has a setup/hold or recovery/removal relationship with another pin, and acts as the reference pin in that relationship. The C pin on an FDRE
IS_ENABLE Synchronous Control that allows or inhibits the data capture of a block. The CE pin on an FDRE
IS_PRESET Asynchronous Forces block output(s) to a 1 state. The PRE pin on an FDPE
IS_RESET Synchronous Changes block output(s) to a 0 state at next clock. The R pin on an FDRE
IS_SET Synchronous Changes block output(s) to a 1 state at next clock. The S pin on an FDSE
IS_SETRESET Programmable Programmable synchronous or asynchronous set/reset. The pin's behavior is controlled by an attribute on the block. The RSTRAMB pin on a RAMB36E2
IS_WRITE_ENABLE Synchronous Enable pin that allows or inhibits the write operation on a memory block. The WES pin on a RAMB36E2

Beyond these properties that define the pin type, the various properties found on PIN objects include the following:

Property	Type	Read-only	Visible	Value
BEL	string	false	true	
BUS_DIRECTION	enum	true	true	
BUS_NAME	string	true	true	
BUS_START	int	true	true	
BUS_STOP	int	true	true	
BUS_WIDTH	int	true	true	
CLASS	string	true	true	pin
CLOCK_DEDICATED_ROUTE	enum	false	true	
DCI_VALUE	int	false	true	
DIRECTION	enum	true	true	IN
FB_ACTIVE	bool	false	true	
HD.ASSIGNED_PPLOCS	string*	true	true	
HD.CLK_SRC	string	false	true	
HD.LOC_FIXED	bool	false	false	0
HD.PARTPIN_LOCS	string*	false	true	
HD.PARTPIN_RANGE	string*	false	true	
HD.PARTPIN_TIEOFF	bool	false	true	
HD.TANDEM	int	false	true	
HIERARCHICALNAME	string	true	false
top.cpuEngine.dwb_biu.\retry_cntr_reg[0]	.C			
HOLD_DETOUR	int	false	true		
HOLD_SLACK	double	true	true	needs timing	update***
IS_CLEAR	bool	true	true	0	
IS_CLOCK	bool	true	true	1	
IS_CONNECTED	bool	true	true	1	
IS_ENABLE	bool	true	true	0	
IS_INVERTED	bool	false	true	0	
IS_LEAF	bool	true	true	1	
IS_ORIG_PIN	bool	true	true	0	
IS_PRESET	bool	true	true	0	
IS_RESET	bool	true	true	0	
IS_REUSED	bool	true	true	0	
IS_SET	bool	true	true	0	
IS_SETRESET	bool	true	true	0	
IS_WRITE_ENABLE	bool	true	true	0	
LOGIC_VALUE	string	true	true	unknown	
MARK_DEBUG	bool	false	true		
NAME	string	true	true		
ORIG_PIN_NAME	string	true	true
PARENT_CELL	cell	true	true
REF_NAME	string	true	true	FDCE
REF_PIN_NAME	string	true	true	C
SETUP_SLACK	double	true	true	needs timing update***
TARGET_SITE_PINS	string*	false	true	
XLNX_LINE_COL	int	false	false	
XLNX_LINE_FILE	long	false	false	

The properties of pins can be listed with the following command:

report_property -all [lindex [get_pins] 0]