ST7232AK2 STMicroelectronics, ST7232AK2 Datasheet - Page 41

• Manufacturer Part Number: ST7232AK2
• Description: 8-BIT MCU WITH 8K FLASH/ROM, ADC, 4 TIMERS, SPI, SCI INTERFACE
• Manufacturer: STMicroelectronics

Specifications of ST7232AK2

• Hdflash Endurance: 100 cycles, data retention
• Clock Sources: crystal/ceramic resonator oscillators and bypass for external clock
• Four Power Saving Modes: Halt, Active-Halt, Wait and Slow
• Main Clock Controller With: Real time base, Beep and Clock-out capabilities
• Two 16-bit Timers With: 2 input captures, 2 output compares, PWM and pulse generator modes

POWER SAVING MODES (Cont’d)
8.4.2.1 Halt Mode Recommendations
– Make sure that an external event is available to
– When using an external interrupt to wake up the
– For the same reason, reinitialize the level sensi-
wake up the microcontroller from Halt mode.
microcontroller, reinitialize the corresponding I/O
as “Input Pull-up with Interrupt” before executing
the HALT instruction. The main reason for this is
that the I/O may be wrongly configured due to ex-
ternal interference or by an unforeseen logical
condition.
tiveness of each external interrupt as a precau-
tionary measure.
– The opcode for the HALT instruction is 0x8E. To
– As the HALT instruction clears the interrupt mask
avoid an unexpected HALT instruction due to a
program counter failure, it is advised to clear all
occurrences of the data value 0x8E from memo-
ry. For example, avoid defining a constant in
ROM with the value 0x8E.
in the CC register to allow interrupts, the user
may choose to clear all pending interrupt bits be-
fore executing the HALT instruction. This avoids
entering other peripheral interrupt routines after
executing the external interrupt routine corre-
sponding to the wake-up event (reset or external
interrupt).
ST7232A
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