ST72124J View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST72124J
STMicroelectronics
'ST72124J' PDF : 153 Pages View PDF
ST72334J/N, ST72314J/N, ST72124J
POWER SAVING MODES (Cont’d)
5.2.3 WAIT Mode
WAIT mode places the MCU in a low power con-
sumption mode by stopping the CPU.
This power saving mode is selected by calling the
“WFI” ST7 software instruction.
All peripherals remain active. During WAIT mode,
the I bit of the CC register is forced to 0 to enable
all interrupts. All other registers and memory re-
main unchanged. The MCU remains in WAIT
Figure 30. WAIT mode flow-chart
mode until an interrupt or Reset occurs, whereup-
on the Program Counter branches to the starting
address of the interrupt or Reset service routine.
The MCU will remain in WAIT mode until a Reset
or an Interrupt occurs, causing it to wake up.
Refer to Figure 30.
WFI INSTRUCTION
OSC ILLATOR
PERIPHERA LS
CPU
I BIT
ON
ON
OFF
0
N
INTERRUPT
Y
N
RESE T
Y
if exit caused by a RESET, a 4096 CPU
clock cycle delay is inserted.
OSC ILLATOR
PE RIPHERALS
CP U
ON
OFF*
OFF
OSC ILLATOR
ON
PE RIPHERALS
ON
CPU
ON
FETCH RESET VECTOR
OR SERVICE INTER RUPT**
Note:
* The peripheral clock is stopped only when exit caused by RESET and not by an interrupt.
** Before servicing an interrupt, the CC register is pushed on the stack.
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