Command controller, prefetch buffer and methods for accessing a serial flash in an embedded system

摘要

The invention relates to a command controller and a prefetch buffer, and in particular, to a command controller and a prefetch buffer for accessing a serial flash in an embedded system. An embedded system comprises a serial flash, a processor, a plurality of access devices, and a prefetch buffer. The processor and the plurality of access devices send various commands to read data from or write data to the serial flash. The prefetch buffer temporarily stores a predetermined amount of data before data being read from or written to the serial flash.

主权项

1. An embedded system comprising a processor, an access device and a serial flash, wherein the processor and the access device send commands to read data from or write data to the serial flash, and the embedded system further comprises:
a serial flash request arbiter, coupled to the processor and the access device; a multiplexer, coupled to the serial flash, operative to selectively shift one instruction from a first instruction and a second instruction to the serial flash for accessing the serial flash; a command interpreter, coupled between the processor and the multiplexer, and operative to interpret a first command to generate the first instruction, wherein the first command is from the processor and not through the serial flash request arbiter; a direct reader, coupled between the serial flash request arbiter and the multiplexer, operative to process a second command to generate the second instruction, wherein the second command can be from at least one of the processor and the access device through the serial flash request arbiter; and a prefetch buffer, operative to temporarily store data before data read from the serial flash is received by the processor or the access device and/or before data is written to the serial flash.