PHILIPS的D12芯片是一款具有并行总线和局部DMA传输能力的高速USB接口器件。D12芯片提供了3个端点，每个端点都有输入和输出端点号各一个，同时端点2还提供了4种方式的数据传输方法。下面对D12的固件编程进行论述，D12固件需要占用单片机的一个硬件中断（INT0或INT1）资源，用于响应D12发出的中断请求。-The D12 PHILIPS chip is a parallel bus and a local high-speed DMA transfer capability USB interface device. D12 chip provides three endpoints, each endpoint has input and output numbers, one each endpoint, and endpoint 2 also provides 4 ways of data transfer methods. Following on the D12' s firmware programming for discussion, D12 firmware needs to occupy a single chip hardware interrupt (INT0 or INT1) resources for the response D12 issued interrupt request.