Low-Power Consumption Modes - Fujitsu FR60 Hardware Manual

CHAPTER 3 CPU AND CONTROL UNITS
3.11.2

Low-power Consumption Modes

This section describes the low-power consumption modes and their use in the states of
the MB91350A model type.
The low-power consumption modes of the MB91350A model type are as follows:
• Sleep mode:
The device enters the sleep state due to writing to a register.
• Stop mode:
The device enters the stop state due to writing to a register.
These modes are described below.
■ Sleep Mode
If "1" is set for Bit 6 (SLEEP bit) of the standby control register (STCR), sleep mode is initiated and the
device enters the sleep state.
The sleep state is maintained until a source for return from the sleep state is generated.
If "1" is set for both Bit 7 (STOP bit) and Bit 6 of the standby control register (STCR), Bit 7 (STOP bit) has
precedence and the device enters the stop state.
For more information about the sleep state, see "❍Sleep State" in Section "3.11.1 Device States and State
Transitions".
[Transition to Sleep Mode]
To enter the sleep mode, use the synchronous standby mode (set with the SYNCS bit as bit 8 in the TBCR,
or time - base counter control register) and be sure to use the following sequence:
(LDI#value_of_sleep,R0)
(LDI#_STCR,R12)
STB R0,@R12
LDUB@R12,R0
LDUB@R12,R0
NOP
NOP
NOP
NOP
NOP
In addition, set the I - flag, the ILM, and ICR registers to branch to an interrupt handler when the interrupt
handler triggers the microcontroller to return from the standby mode.
138
; value_of _sleep is write data to STCR.
; _STCR is address (481H) of STCR.
; Writing in standby control register (STCR)
; STCR read for synchronous standby
; Dummy re - read of STCR
; NOP for timing adjustment: x5