ST7263 STMICROELECTRONICS [STMicroelectronics], ST7263 Datasheet - Page 24

• Manufacturer Part Number: ST7263
• Description: LOW SPEED USB 8-BIT MCU FAMILY with up to 16K MEMORY, up to 512 BYTES RAM, 8-BIT ADC, WDG, TIMER, SCI & I2C
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST7263
POWER SAVING MODES (Cont’d)
4.2.3 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
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
24/109
Figure
17.
Figure 17. WAIT Mode Flow Chart
Note: Before servicing an interrupt, the CC register is
pushed on the stack. The I-Bit is set during the inter-
rupt routine and cleared when the CC register is
popped.
N
INTERRUPT
Y
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
N
OR SERVICE INTERRUPT
FETCH RESET VECTOR
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
WFI INSTRUCTION
4096 CPU CLOCK
CYCLES DELAY
IF RESET
RESET
Y
ON
ON
OFF
CLEARED
ON
ON
ON
SET