Texas Instruments MSP430x1xx manual Operating Modes

Operating Modes

2.3 Operating Modes

The MSP430 family is designed for ultralow-power applications and uses different operating modes shown in Figure 2−10.

The operating modes take into account three different needs:

-Ultralow-power

-Speed and data throughput

-Minimization of individual peripheral current consumption The MSP430 typical current consumption is shown in Figure 2−9.

Figure 2−9. Typical Current Consumption of 13x and 14x Devices vs Operating Modes

ICC/ ∝A @ 1 MHz

315

270

225

180

135

90

45

0

340
225
	70	65
AM	LPM0

17	11	2	1
LPM2		LPM3

Operating Modes

VCC = 3 V

VCC = 2.2 V

0.1 0.1

LPM4

The low-power modes 0−4 are configured with the CPUOFF, OSCOFF, SCG0, and SCG1 bits in the status register The advantage of including the CPUOFF, OSCOFF, SCG0, and SCG1 mode-control bits in the status register is that the present operating mode is saved onto the stack during an interrupt service routine. Program flow returns to the previous operating mode if the saved SR value is not altered during the interrupt service routine. Program flow can be returned to a different operating mode by manipulating the saved SR value on the stack inside of the interrupt service routine. The mode-control bits and the stack can be accessed with any instruction.

When setting any of the mode-control bits, the selected operating mode takes effect immediately. Peripherals operating with any disabled clock are disabled until the clock becomes active. The peripherals may also be disabled with their individual control register settings. All I/O port pins and RAM/registers are unchanged. Wake up is possible through all enabled interrupts.

2-14System Resets, Interrupts, and Operating Modes