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Notes on Accessing the Low-Power Consumption Made Control Register (LPMCR) to Enter the Standby
Mode
G
To access the low-power consumption mode control register (LPMCR) with assembler language
• To set the low power consumption mode control register (LPMCR) to enter the standby mode, use the
instruction listed in Table 3.8-2.
• The standby mode transition instruction in Table 3.8-2 must always be followed by an array of
instructions highlighted by a line below.
MOV LPMCR,#H'xx
NOP
NOP
JMP $+3
MOV A,#H'10
The devices does not guarantee its operation after returning from the standby mode if you place an array of
instructions other than the one enclosed in the line,
G
To access the low-power consumption mode (LPMCR) with C language
To enter the standby mode using the low power consumption mode control register (LPMCR), use one of
the following methods (1) to (3) to access the register:
(1) Specify the standby mode transition instruction as a function and insert two __wait_nop() built-in
functions after that instruction.If any interrupt other than the interrupt to return from the standby mode
can occur within the function, optimize the function during compilation to suppress the LINK and
UNLINK instructions from occurring.
Example: Watch mode or timebase timer mode transition function
void enter_watch(){
IO_LPMCR.byte = 0x10; /* Set LPMCR TMD bit to 0 */
__wait_nop();
__wait_nop();
}
(2) Define the standby mode transition instruction using __asm statements and insert two NOP and JMP
instructions after that instruction.
Example: Transition to sleep mode
__asm("
__asm("
__asm("
__asm("
; The low-power consumption mode transition instruction in Table 3.8-2
; Jump to the next instruction
; Arbitary instruction
MOVI;_IO_LPMCR,#H'58); /* Set LPMCR SLP bit to 1 */
NOP");
NOP");
JMP $+3");
/* Jump to the next instruction */
CHAPTER 3 CPU
149
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