Chapter 5 – Architecture of the MSP430 Processor

Publisher Summary The chapter describes the central processing unit (CPU) of the MSP430 and its most closely associated modules, the clock generator and reset circuitry. It begins with a description of the central processing unit (CPU) and its instruction set, which is highly significant in assembly language programming for several reasons. Foremost is debugging. Also, many of the examples in TI’s application notes are written in assembly language. In any case the MSP430 is not complicated. The CPU has only 27 instructions, most of which can use all appropriate addressing modes (up to 7). Its large number of general-purpose registers can hold many variables and addresses. There are four special-purpose registers: program counter, stack pointer, status register, constant generators, and 12 general-purpose registers. Following this, it describes the ways in which operands can be specified (addressing modes). Thereafter, it describes the instruction set, using a few examples. With this understanding, it explains the CPU and instruction set of the MSP430, finally explaining the architecture of the MSP430 processor.