IMPROVEMENTS IN MICROPROCESSOR DEVELOPMENT SYSTEMS

摘要

In one aspect, in order to avoid lengthy delays in debug procedures during access by a memory mapped peripheral device, in a processor including in-circuit emulation means comprising one or more scan chains of serially connected registers for access by an external host computer system, the procedure comprises: a) the host computer system carrying out a debug procedure via said scan chains, and selectively interrupting such debug procedure for access to a peripheral memory mapped device; b) the host computer system writing into an area of memory of the processor a program for reading and/or writing data at a specified memory location; and c) the host computer system causing said processor to run said program, and then to return to said debug procedure. In another aspect, in order to permit small debugging programs to run, in serial scan in circuit emulation processes, on a processor in a deeply embedded application where no program RAM is provided, the processor includes one or more chains of serially connected registers coupled to interface means for access by an external host to enable a serial scan procedure to be carried out, one such chain including a set of serially coupled registers for storing one or more processor instructions read into a set of registers through the interface means, and the processor including address means, for addressing program memory, coupled to said set of registers for addressing the set of registers, and means for reading the processor instructions in the set of registers to an instruction register of the processor.