MSP430C32x, MSP430P325A

MIXED SIGNAL MICROCONTROLLER

SLAS219B – MARCH 1999 – REVISED MARCH 2000

5

POST OFFICE BOX 655303

Table 2. Address Mode Descriptions

ADDRESS MODE

s

d

SYNTAX

EXAMPLE

OPERATION

Register

√

√

MOV Rs, Rd

MOV R10, R11

R10

→ R11

Indexed

√

√

MOV X(Rn), Y(Rm)

MOV 2(R5), 5(R6)

M(2 + R5)

→ M(6 + R6)

Symbolic (PC relative)

√

√

MOV EDE, TONI

M(EDE)

→ M(TONI)

Absolute

√

√

MOV &MEM, &TCDAT

M(MEM)

→ M(TCDAT)

Indirect

√

MOV @Rn, Y(Rm)

MOV @R10, Tab(R6)

M(R10)

→ M(Tab + R6)

Indirect autoincrement

√

MOV @Rn+, RM

MOV @R10+, R11

M(R10)

→ R11, R10 + 2 → R10

Immediate

√

MOV #X, TONI

MOV #45, TONI

#45

→ M(TONI)

NOTE: s = source

d = destination

Computed branches (BR) and subroutine calls (CALL) instructions use the same addressing modes as the other

instructions. These addressing modes provide

indirect addressing, ideally suited for computed branches and

calls. The full use of this programming capability permits a program structure different from conventional 8- and

16-bit controllers. For example, numerous routines can easily be designed to deal with pointers and stacks

instead of using flag type programs for flow control.

operation modes and interrupts

The MSP430 operating modes support various advanced requirements for ultra low power and ultra low energy

consumption. This is achieved by the intelligent management of the operations during the different module

operation modes and CPU states. The requirements are fully supported during interrupt event handling. An

interrupt event awakens the system from each of the various operating modes and returns with the RETI

instruction to the mode that was selected before the interrupt event. The clocks used are ACLK and MCLK.

ACLK is the crystal frequency and MCLK is a multiple of ACLK and is used as the system clock.

The software can configure five operating modes:

are active, and loop control for MCLK is active.

are active, and loop control for MCLK is inactive.

and MCLK and loop control for MCLK are inactive.

MCLK and loop control for MCLK are inactive, and the dc generator for the digital controlled oscillator (DCO)

(

³MCLK generator) is switched off.

(crystal oscillator stopped), MCLK and loop control for MCLK are inactive, and the dc generator for the DCO

is switched off.

The special function registers (SFR) include module-enable bits that stop or enable the operation of the specific

peripheral module. All registers of the peripherals may be accessed if the operational function is stopped or

enabled. However, some peripheral current-saving functions are accessed through the state of local register

bits. An example is the enable/disable of the analog voltage generator in the LCD peripheral, which is turned

on or off using one register bit.