MSP430 and MSP430X Instructions
4-36
16-Bit MSP430X CPU
4.5
MSP430 and MSP430X Instructions
MSP430 instructions are the 27 implemented instructions of the MSP430
CPU. These instructions are used throughout the 1-MB memory range unless
their 16-bit capability is exceeded. The MSP430X instructions are used when
the addressing of the operands or the data length exceeds the 16-bit capability
of the MSP430 instructions.
There are three possibilities when choosing between an MSP430 and
MSP430X instruction:
-
To use only the MSP430 instructions: The only exceptions are the CALLA
and the RETA instruction. This can be done if a few, simple rules are met:
J
Placement of all constants, variables, arrays, tables, and data in the
lower 64 KB. This allows the use of MSP430 instructions with 16-bit
addressing for all data accesses. No pointers with 20-bit addresses
are needed.
J
Placement of subroutine constants immediately after the subroutine
code. This allows the use of the symbolic addressing mode with its
16-bit index to reach addresses within the range of PC
±
32 KB.
-
To use only MSP430X instructions: The disadvantages of this method are
the reduced speed due to the additional CPU cycles and the increased
program space due to the necessary extension word for any double
operand instruction.
-
Use the best fitting instruction where needed
The following sections list and describe the MSP430 and MSP430X
instructions.
Содержание MSP430x4xx Family
Страница 1: ...MSP430x4xx Family 2007 Mixed Signal Products User s Guide SLAU056G ...
Страница 2: ......
Страница 6: ...vi ...
Страница 114: ...3 76 RISC 16 Bit CPU ...
Страница 304: ...5 20 FLL Clock Module ...
Страница 340: ...7 8 Supply Voltage Supervisor ...
Страница 348: ...8 8 16 Bit Hardware Multiplier ...
Страница 372: ...9 24 32 Bit Hardware Multiplier ...
Страница 400: ...10 28 DMA Controller ...
Страница 428: ...13 10 Basic Timer1 ...
Страница 466: ...15 24 Timer_A ...
Страница 522: ...17 30 USART Peripheral Interface UART Mode ...
Страница 544: ...18 22 USART Peripheral Interface SPI Mode ...
Страница 672: ...23 12 Comparator_A ...
Страница 692: ...24 20 LCD Controller ...
Страница 746: ...26 28 ADC12 ...