通信工程英文中英文翻译.DOC

1.dsPIC30F CPU The dsPIC30F CPU module has a 16-bit (data) modified Harvard architecture with an enhanced instruction set, including significant support for DSP. The CPU has a 24-bit instruction word, with a variable length opcode field. The program counter (PC) is 24-bits wide and addresses up to 4M x 24 bits of user program memory space. A single cycle instruction pre-fetch mechanism is used to help maintain throughput and provides predictable execution. All instructions execute in a single cycle, with the exception of instructions that change the program flow, the double-word move (MOV.D) instruction and the table instructions. Overhead free program loop constructs are supported using the DO and REPEAT instructions, both of which are interruptible at any point. The dsPIC30F devices have sixteen 16-bit working registers in the programmer’s model. Each of the working registers can act as a data, address, or address offset register. The 16th working register (W15) operates as a software stack pointer for interrupts and calls. The dsPIC30F instruction set has two classes of instructions: the MCU class of instructions and the DSP class of instructions. These two instruction classes are seamlessly integrated into the architecture and execute from a single execution unit. The instruction set includes many Addressing modes and was designed for optimum C compiler efficiency. The data space can be addressed as 32K words or 64 Kbytes and is split into two blocks, referred to as X and Y data memory. Each memory block has its own independent Address Generation Unit (AGU). The MCU class of instructions operate solely through the X memory AGU, which accesses the entire memory map as one linear data space. Certain DSP instructions operate through the X and Y AGUs to support dual operand reads, which splits the data address space into two parts. The X and Y data space boundary is device specific. The upper 32 Kbytes of the data space memory map can optionally be mapped into prog