Logic array

The logic array (British: gate array) is called ULA (British: uncommitted logic array) in one of the design and fabrication technique of the ASIC. I locate the parts such as the passive elements such as logical circuits such as standard NAND gate or NOR, a transistor, the resistor of the simple substance in fixed form on the wafer and I wire each part by adding the class of wiring to the top and complete a semiconductor circuit. A digital semiconductor is the main constituent, but is not limited [¹].

Table of contents

Characteristic

Characteristic of the process

By the production of the logic array, it produces the wafers to the half completion state that elaborated elements such as the logic gate called the master slice (British: master slice) regardless of an order in large quantities beforehand and holds it as stock, and wiring is decided by the order from a customer, and what I complete as a semiconductor product by building the class of metal wiring more as the upper air of the master slice is common.

A gate and wiring

Number of the logic gate and wiring space or IO must be enough to locate a certain applied circuit on the logic array. Therefore, the logic array is often offered as the family which prepared a variation, and, as for many things of the number of the logic gate, dghaisa is becomes greatly expensive [¹]. The necessary number of the logic gate and number of IO are counted up easily, but the complexity of the wiring is greatly different by a circuit even if the number of the gates is the same. For example, the crossbar switch needs the wiring that is greater than cyst Rick array of the number of the same gates. The unused wiring truck is good for nothing, but I raise cost and reduce performance. Therefore the logic array manufacturer keeps it in mind to provide the wiring truck which just balanced with the number of the logic gate and the number of IO. I use the law of Lent for this estimate and utilize the experience by the existing design.

Good point

I draw a figure of a mask pattern of the wiring layer from the connection diagram of the customer, and the customer can receive a finished product after an order more quickly than a standard cell method and a full custom method relatively briefly during production, inspection, the period to suffer before it is completed. There is little master number of the masks which are necessary every product of the customer that photomask of slicing it is common and finishes it and finishes it and, by the logic array method, can reduce cost of a design and the production of the mask. Furthermore, I can reduce cost for the run-up of the test because I can considerably commonize the test tool with the logic array product prepared by the same dghaisa is [¹].

Bad point

The logic array has lower implementation density than other ASIC design methods, and the performance lowers, too. However, it is often said that this is the most realistic when there is little production number. I only choose a dghaisa is and process technology, the logic technique among a thing prepared beforehand [¹].

Similar parts

The full custom design costs, and the needs to be cheaper, and to want to produce complicated tips is the way it goes. It is FPGA, CPLD, strike comfortable Chard ASIC to meet the needs now. Semiconductor plant equipment for wiring is necessary for ULA (logic array), but FPGA can program wiring.

Past use example

Sinclair Research made the thing which improved a design of ZX80 ULA tip and used it in ZX81 and adopted ULA in later ZX Spectrum. The compatible tip was made as T34VG1^[2] in Russia. The ray corn computer used some ULA tips in BBC Micro, too. Integrate those ULA tips with one tip later Acorn ElectronI developed (ray corn electron). At that time of the hobby PC heyday, I used ULA well in other makers. A pioneer company of the ULA technology included フェランティ in the U.K., but was robbed of market by a semi-custom tip afterwards. IBM PC comes to sweep over a PC market, and even a semi-custom tip is because I came to face each other economically because sales figures became big.

Allied item

• FPGA
• System LSI

References

1. ^ ^{a b c d} Masanori Kikuchi supervision "semiconductor and system LSI," it is Japanese business publishing company, July 1, 2006 first edition publication, ISBN 4534040865
2. ^ ru: Item (Russian) about the tip compatible with Т34ВГ1 - ZX Spectrum ULA

It is acquired by "https://ja.wikipedia.org/w/index.php?title= logic array &oldid=55045007"

This article is taken from the Japanese Wikipedia Logic array

This article is distributed by cc-by-sa or GFDL license in accordance with the provisions of Wikipedia.

Wikipedia and Tranpedia does not guarantee the accuracy of this document. See our disclaimer for more information.

In addition, Tranpedia is simply not responsible for any show is only by translating the writings of foreign licenses that are compatible with CC-BY-SA license information.