DSP Data Acquisition Board Based On USB Interface

USB(Universal Serial Bus) interface is a newly bus interface standard. It has flexible power supply mode, very high transfer rate and plug and play virtue. At the same time because DSP(Digital Signal Processing) chip is preponderant in data processing and price, it has accelerated growth in recent years. Combination them meets industry Test Control field requirement that is flexible, portable, high precision and miniaturized.The traditional mode usually exchanges data with PC by ISA or PCI interface slots. However, internal cards can be easily influenced by high frequency interference within PC mainframe, resulting in reduction of collection precision and system reliable. Furthermore, the numbers of slots in the mainframe are limited. With the increase of various peripheral equipment, people must work out a new, higher data transfer rate, external stand alone data acquisition board. The paper designed a DSP data acquisition board based on USB interface. It proves that the data acquisition boad runs steady and realtime afer testing.At first, the paper introduces the architecture of TMS320F240, PDIUSBD12 and EPM7064; then the design method of connection and time sequence is given in detail; the data acquisition board schematic and PCB are accomplished by Protel99 SE; meanwhile the matter of building system and drawing PCB is described particular. Secondly, the paper introduces the protocol of USB1. 1 and implement method in brief, including procedure for enumeration of USB device, standard device request and device descriptor etc. At last, the paper discusses the firmware design in detail. Flowchart of interrupt service routine, standard device request and main routine are given.