Abstract:

The process of adding SKP is usually completed by breakpoint restoration and pointer jump in an elastic buffer. Aiming at the problems of complex asynchronous logic circuit design and possible timing errors caused by this realization method, we propose a novel technique to achieve SKP adding by the read pointer pause. Firstly, the threshold monitor checks the amount of valid data, which are then compared with the adding threshold to generate an adding instruction. Secondly, we make the read pointer pause and add the SKP to the output data, which guarantees the state of elastic buffer at half-full by raising the volume of effective data. Experimental results show that the proposed elastic buffer can achieve the function of SKP adding and removing correctly while both the read and write frequencies of the buffer can reach 500MHz, which meets the design requirements of universal serial bus 3.0 (USB 3.0).

Key words: USB 3.0, elastic buffer, read pointer, SKP, clock domain