是基于apb总线下的timer外设的rtl代码，主要包括apb_timer的master逻辑verilog，以及相应的开发文档，包括寄存器的描述，功能特性等。(RTL code is based on timer peripheral under APB bus, which mainly includes master logic Verilog of apb_timer and corresponding development documents, including the descr iption of registers, functional characteristics and so on.)