ST7FOXK1 STMicroelectronics, ST7FOXK1 Datasheet - Page 113

• Manufacturer Part Number: ST7FOXK1
• Description: Low cost flash 8bit micro
• Manufacturer: STMicroelectronics

Specifications of ST7FOXK1

• 4 To 8 Kbytes Single Voltage Extended Flash (xflash) Program Memory With Read-out Protection In-circuit Programming And In-application Programming (icp And Iap) Endurance: 1K write/erase cycles guaranteed Data retention
• Clock Sources: Internal trimmable 8 MHz RC oscillator, auto wakeup internal low power - low frequency oscillator, crystal/ceramic resonator or external clock
• Five Power Saving Modes: Halt, Active-Halt, Auto Wakeup from Halt, Wait and Slow
• A/d Converter: up to 10 input channels

ST7FOXF1, ST7FOXK1, ST7FOXK2
10.3.4
In this case, the HALT instruction stops the oscillator. When the oscillator is stopped, the Lite
timer stops counting and is no longer able to generate a Watchdog reset until the
microcontroller receives an external interrupt or a reset.
If an external interrupt is received, the WDG restarts counting after 4096 CPU clocks. If a
reset is generated, the Watchdog is disabled (reset state).
Recommendations
Figure 54. Watchdog timing diagram
Low power modes
Table 39.
WDGD BIT
INTERNAL
WATCHDOG
RESET
f
WDG
Make sure that an external event is available to wake up the microcontroller from Halt
mode.
Before executing the HALT instruction, refresh the WDGD bit, to avoid an unexpected
Watchdog reset immediately after waking up the microcontroller.
When using an external interrupt to wake up the 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
external interference or by an unforeseen logical condition.
For the same reason, reinitialize the level sensitiveness of each external interrupt as a
precautionary measure.
Active Halt
Mode
Slow
Effect of low power modes on Lite timer 2
Wait
Halt
(2ms @ 8MHz f
t
WDG
OSC
SOFTWARE SETS
WDGD BIT
)
HARDWARE CLEARS
WDGD BIT
(this peripheral is driven directly by f
Lite timer stops counting
No effect on Lite timer
No effect on Lite timer
No effect on Lite timer
Description
WATCHDOG RESET
On-chip peripherals
OSC
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