Based On Usb2.0 Configuration Interface Circuit Hardware And Software Design And Implementation

With rapid developments of system on chip (SOC), programmable logic devices (PLD), including complex programmable logic device (CPLD) and field programmable gate array (FPGA) which can support in-system programmability (ISP) become more and more popular. This trend also set higher standard to configuration interface circuit than ever before, which are used to program PLDs.At present, configuration interface circuits are divided into two classes. One is base on PC's parallel port, and another on USB interface. Because of higher download speed and more convenience the later is of more advancement. But its application is limited because that it's price is relatively higher and PLD manufactures keep a secret to protect their intellectual Property. This situation also set more difficulty to researchers to design it by themselves.This article researches how to design and accomplish universal serial bus (USB) download interface circuit based on IEEE std.1149.1 specification. Based on deep comprehension of IEEE std.1149.1 specification and USB principle, the author contraposed USB-Blaster, a kind of USB download interface circuit which is special used in Altera and analysised it inter communication system then actualized the total software and hardware design of USB download interface circuit and accomplished the configuration function of Altera serials PLDs.Be different with those USB configuration interface circuit already exist, the download interface circuit designed in this article is aim to be compatible in Altera integrated design environment named QuartusII. Those design excised already always need to design a software terminal to control the communication between configuration interface circuit and object programmable device. But it's not convenient for usage, and what's more, it may beget compatible problem in deferent operation system. The USB configuration interface circuit discussed in this article has already be proved can be directly used in QuartusII with higher compatible capability.Compared with traditional configuration cable based on PC' parallel port, the configuration circuit based PC's USB port has many advantages, such as hot-plugging, compact, rapid, convenient in installing. According to the price, the USB configuration interface circuit has good ability of competition to its counterpart.