Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Place and route
open-in-new
<p>Place and route (also called PnR or P&R) is a stage in the design of <a href="/facts/Printed_circuit_board/muSR2p43">printed circuit boards</a>, <a href="/facts/Integrated_circuits/fjn6vg7C">integrated circuits</a>, and <a href="/facts/Field-programmable_gate_array/M8LSGcAU">field-programmable gate arrays</a>. As implied by the name, it is composed of two steps, <a href="/facts/Placement_(EDA)/lcheSkIL">placement</a> and <a href="/facts/Routing_(electronic_design_automation)/fMFz74oA">routing</a>. The first step, placement, involves deciding where to place all <a href="/facts/Electronic_components/F3NBVv4Q">electronic components</a>, <a href="/facts/Circuitry/IRfQ6Cc2">circuitry</a>, and <a href="/facts/Logic/8JnpJLtt">logic</a> elements in a generally limited amount of space. This is followed by routing, which decides the exact design of all the wires needed to connect the placed components. This step must implement all the desired connections while following the rules and limitations of the manufacturing process. </p><p>Place and route is used in several contexts: </p> <ul><li><a href="/facts/Printed_circuit_board/muSR2p43">Printed circuit boards</a>, during which <a href="/facts/Electronic_component/F3NBVv4Q">components</a> are graphically placed on the board and the wires drawn between them</li> <li><a href="/facts/Integrated_circuit/fjn6vg7C">Integrated circuits</a>, during which a <a href="/facts/Integrated_circuit_layout/96BnDlT2">layout</a> of a larger block of the circuit or the whole circuit is created from layouts of smaller sub-blocks</li> <li><a href="/facts/Field-programmable_gate_array/M8LSGcAU">FPGAs</a>, during which <a href="/facts/Logic/8JnpJLtt">logic</a> elements are placed and interconnected on the grid of the FPGA</li></ul> <p>These processes are similar at a high level, but the actual details are very different. With the large sizes of modern designs, this operation is usually performed by <a href="/facts/Electronic_design_automation/o4la3fmX">electronic design automation</a> (EDA) tools. </p><p>In all these contexts, the final result when placing and routing is finished is the "layout", a geometric description of the location and rotation of each part, and the exact path of each wire connecting them. </p><p>Occasionally some people call the entire place-and-route process "layout". </p>