## Assigning Pins, Logic Cells & Chips

You can assign a single logic function to a specific pin or logic cell (including I/O cells and embedded cells) within a chip, and assign one or more functions to a specific chip. A chip is a group of logic functions defined as a single, named unit, which can be assigned to a specific device.

You can assign a signal to a particular pin to ensure that the signal is always associated with that pin, regardless of future changes to the project. If you wish to set and maintain the performance of your project, assigning logic to a specific logic cell within a chip can minimize timing delays. In a project that is partitioned among multiple devices, you can assign logic functions that must be kept together in the same device to a chip. Chip assignments allow you to split a project so that only a minimum number of signals travel between devices, and to ensure that no unnecessary device-to-device delays exist on critical timing paths. You can assign a chip to a device in MAX+PLUS® II software.

To make pin, logic cell, and chip assignments, use the `set_attribute` command at a dc_shell prompt. Before using the `set_attribute` command, add the following line to your .synopsys_dc.setup file:

`edifout_write_properties_list` = {`LOGIC_OPTION, CLIQUE, CHIP_PIN_LC`}

Table 1 shows the syntax to use for chip, pin, and logic cell assignments:

Table 1. Commands for Chip, Pin, & Logic Cell Assignments
Assignment Type | Command to Type Note (1)
Chip | `set_attribute find (`<design object>`, (`<instance name>`)) "CHIP_PIN_LC" -type string "`<chip name>`"`
Pin | `set_attribute find (`<design object>`, (`<instance name>`)) "CHIP_PIN_LC" -type string "`<chip name>`@`<pin number>`"`
Logic cell number | `set_attribute find (`<design object>`, (`<instance name>`)) "CHIP_PIN_LC" -type string "`<chip name>`@LC`<logic cell number>`"`
I/O cell number | `set_attribute find (`<design object>`, (`<instance name>`)) "CHIP_PIN_LC" -type string "`<chip name>`@IOC`<I/O cell number>`"`
Embedded cell number | `set_attribute find (`<design object>`, (`<instance name>`)) "CHIP_PIN_LC" -type string "`<chip name>`@EC`<embedded cell number>`"`

Note:

1. In this table, <design object> represents ports, references, cells, nets, or pins.

Examples:

`set_attribute find (cell, (U1)) "CHIP_PIN_LC" -type string "chip1"`

`set_attribute find (cell, (U1)) "CHIP_PIN_LC" -type string "chip1@K2"`

`set_attribute find (cell, (U1)) "CHIP_PIN_LC" -type string "chip1@LC44"`

| Go to "Devices & Adapters" and "Assigning a Device" in MAX+PLUS II Help for information on device pin-outs and assigning devices, respectively, in the MAX+PLUS II software.

Last Updated: August 28, 2000 for MAX+PLUS II version 10.0 |
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