pin_assign

Use to either assign the named pin to the specified port or assign attributes to the specified port. This command has two syntax formats. The one you use depends on what you are trying to do. The first syntax format assigns the named pin to the specified port and supports all families. The second one assigns attributes to the specified port but supports only the ProASIC3/E, Axcelerator, SX-A, RTSX-S, and eX families.

 

pin_assign [-nofix] -port portname -pin pin_number

pin_assign -port portname [-iostd value][-iothresh value][-outload value][-slew value][-res_pull value]

Arguments

-nofix

Unlocks the pin assignment (by default, assignments are locked).

 

-port portname

Specifies the name of the port to which the pin is assigned.

 

-pin pin_number

Specifies the alphanumeric number of the pin to assign.

 

-iostd value

Sets the I/O standard for this pin. Choosing a standard allows the software to set other attributes such as the slew rate and output loading. If the voltage standard used with the I/O is not compatible with other I/Os in the I/O bank, then assigning an I/O standard to a port will invalidate its location and automatically unassign the I/O. The following table shows the acceptable values for the supported devices:

 

I/O Standard

ProASIC3E

Axcelerator

ProASIC3

RTSX-S

SX-A

eX

CMOS

 

 

 

X

 

 

CUSTOM

 

 

 

X

X

X

GTLP25

X

X

 

 

 

 

GTLP33

X

 

 

 

 

 

GTL33

X

X

 

 

 

 

GTL25

X

X

 

 

 

 

HSTL1

X

X

 

 

 

 

HSTLII

X

 

 

 

 

 

LVCMOS33

X

 

X

 

 

 

LVCMOS25

X

X

 

 

 

 

LVCMOS25_50

X

 

X

 

 

 

LVCMOS18

X

X

X

 

 

 

LVCMOS15

X

X

X

 

 

 

LVTTL

X

X

X

X

X

 

TTL

X

X

X

X

X

 

PCI

X

X

X

X

X

X

PCIX

X

X

X

 

 

 

SSTL2I

X

X

 

 

 

 

SSTL2II

X

X

 

 

 

 

SSTL3I

X

X

 

 

 

 

SSTL3II

X

X

 

 

 

 

 

Note: The LVDS and LVPECL I/O standards cannot be set through a script.

 

-iothresh value

Sets the compatible threshold level for inputs and outputs. The default I/O threshold is based upon the I/O standard. You can set the I/O Threshold independently of the I/O specification in the PinEditor tool by selecting CUSTOM in the I/O Standard cell. The following table shows the acceptable values for the supported devices (SX-A, RTSX-S, and eX):

 

Value

Description

CMOS

RTSX-S devices only. An advanced integrated circuit (IC) manufacturing process technology for logic and memory, characterized by high integration, low cost, low power, and high performance. CMOS logic uses a combination of p-type and n-type metal-oxide-semiconductor field effect transistors (MOSFETs) to implement logic gates and other digital circuits found in computers, telecommunications, and signal processing equipment.  

LVTTL

(Low-Voltage TTL) A general purpose standard (EIA/JESDSA) for 3.3V applications. It uses an LVTTL input buffer and a push-pull output buffer.

PCI

A computer bus for attaching peripheral devices to a computer motherboard in a local bus. This standard supports both 33 MHz and 66 MHz PCI bus applications. It uses an LVTTL input buffer and a push-pull output buffer. With the aid of an external resistor, this I/O standard can be 5V-compliant for most families, excluding ProASIC3/E families.

 

Note: The -iothresh attribute is also referred to as "Loading" in some families.

 

-slew value

Sets the output slew rate. Slew control affects only the falling edges. Rising edges are not affected. This attribute is only available for LVTTL, PCI, and PCI outputs. For LVTTL, it can either be high or low. For PCI and PCIX, it can only be set to high. The following table shows the acceptable values for the supported devices (ProASIC3/E, Axcelerator, SX-A, RTSX-S, and eX):

 

Value

Description

high

Sets the I/O slew to high

low

Sets the I/O slew to low

 

-res_pull value

Allows you to include a weak resistor for either pull-up or pull-down of the input buffer. The following table shows the acceptable values for the supported devices (ProASIC3/E, Axcelerator, SX-A, RTSX-S, and eX):

 

Value

Description

up

Includes a weak resistor for pull-up of the input buffer

down

Includes a weak resistor for pull-down of the input buffer

none

Does not include a weak resistor

 

-out_load value

Indicates the output-capacitance value based on the I/O standard selected. This option is not available in ACTgen. This attribute determines what Timer will use as the loading on the output pin and applies only to outputs. You can enter a capacitive load as an integral number of picofarads (pF). The default is 35pF. This attribute is available only for the following devices: ProASIC3/E, Axcelerator, SX-A, RTSX-S, and eX.

Supported Families

The first syntax statement for pin_assign supports all families. The second one supports only Fusion, ProASIC3/E, Axcelerator, SX-A, RTSX-S, and eX families.

Exceptions

Examples

You must use pin_commit after the pin_assign command to save the changes to your design:

 

pin_assign -port usw0 -pin A2

pin_commit

 

pin_assign -port usw0 -iostd LVTTL -slew low -res_pull down

pin_commit

See Also

pin_commit

pin_fix

pin_unassign

Tcl documentation conventions