Patent ID: 9274986
Filing Date: 2016-03-01
CPC Classification: G06F,H04N

Claim Text:
1. A data transmission circuit applied to a universal serial bus (USB) system, comprising: a memory, arranged for receiving and storing external data; a direct memory access (DMA) engine, coupled to the memory and arranged for controlling data retrieved from the memory; and a USB controller, coupled to the DMA engine, the USB controller arranged for receiving data from the DMA engine and for transmitting the received data to a host; wherein the DMA engine starts to fetch data from the memory when a data volume of stored data in the memory changes from a first value to a first threshold while in the memory, transmits fetched data to the USB controller until a data volume of the fetched data reaches a second threshold or no data left in the memory, and the first value is lower than the first threshold, and the second threshold is greater than the first threshold; wherein a transmission bandwidth between the memory and the DMA engine is less than a transmission bandwidth between the USB controller and the host.