ST72215G2 STMicroelectronics, ST72215G2 Datasheet - Page 28

• Manufacturer Part Number: ST72215G2
• Description: 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY,ADC, 16-BIT TIMERS, SPI, I2C INTERFACES
• Manufacturer: STMicroelectronics

Specifications of ST72215G2

• Emulation Voltage: 5.5 V

ST72104Gx, ST72215Gx, ST72216Gx, ST72254Gx
POWER SAVING MODES (Cont’d)
8.3 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
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
28/141
Figure
18.
Figure 18. WAIT Mode Flow-chart
Note:
1. Before servicing an interrupt, the CC register is
pushed on the stack. The I bit of the CC register is
set during the interrupt routine and cleared when
the CC register is popped.
WFI INSTRUCTION
N
INTERRUPT
Y
OR SERVICE INTERRUPT
FETCH RESET VECTOR
4096 CPU CLOCK CYCLE
OSCILLATOR
PERIPHERALS
CPU
I BIT
OSCILLATOR
PERIPHERALS
CPU
I BIT
OSCILLATOR
PERIPHERALS
CPU
I BIT
N
DELAY
RESET
Y
OFF
OFF
X
ON
ON
ON
ON
ON
ON
ON
0
1
1)