MSP430x41x
MIXED SIGNAL MICROCONTROLLER
SLAS340J − MAY 2001 − REVISED DECEMBER 2008
short-form description
CPU
The MSP430 CPU has a 16-bit RISC architecture
that is highly transparent to the application. All
operations, other than program-flow instructions,
are performed as register operations in
conjunction with seven addressing modes for
source operand and four addressing modes for
destination operand.
The CPU is integrated with 16 registers that
provide reduced instruction execution time. The
register-to-register operation execution time is
one cycle of the CPU clock.
Four of the registers, R0 to R3, are dedicated as
program counter, stack pointer, status register,
and constant generator, respectively. The
remaining registers are general-purpose
registers.
Peripherals are connected to the CPU using data,
address, and control buses, and can be handled
with all instructions.
instruction set
The instruction set consists of 51 instructions with
three formats and seven address modes. Each
instruction can operate on word and byte data.
Table 1 shows examples of the three types of
instruction formats; the address modes are listed
in Table 2.
Program Counter
Stack Pointer
Status Register
Constant Generator
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
General-Purpose Register
PC/R0
SP/R1
SR/CG1/R2
CG2/R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
Table 1. Instruction Word Formats
Dual operands, source-destination
Single operands, destination only
Relative jump, un/conditional
e.g. ADD R4,R5
e.g. CALL
e.g. JNE
R8
R4 + R5 −−−> R5
PC −−>(TOS), R8−−> PC
Jump-on-equal bit = 0
Table 2. Address Mode Descriptions
ADDRESS MODE
Register
Indexed
Symbolic (PC relative)
Absolute
Indirect
Indirect
autoincrement
Immediate
NOTE: S = source
S D
SYNTAX
MOV Rs,Rd
MOV X(Rn),Y(Rm)
MOV EDE,TONI
MOV &MEM,&TCDAT
MOV @Rn,Y(Rm)
MOV @Rn+,Rm
MOV #X,TONI
MOV @R10,Tab(R6)
MOV @R10+,R11
MOV #45,TONI
EXAMPLE
MOV R10,R11
MOV 2(R5),6(R6)
OPERATION
R10
−−> R11
M(2+R5)−−> M(6+R6)
M(EDE) −−> M(TONI)
M(MEM) −−> M(TCDAT)
M(R10) −−> M(Tab+R6)
M(R10) −−> R11
R10 + 2−−> R10
#45
−−> M(TONI)
D
D
D
D
D
D
D
D
D
D
D
D = destination
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
9