ST10R272L - SYSTEM RESET
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1
Current external bus cycle is completed for Watchdog reset only.
2
If during the reset condition (RSTIN low), RPD/Vpp voltage drops below the threshold
voltage (about 2.5V for 5V operation and 2.0V for 3.3V operation), the asynchronous
reset is then immediately entered.
3
RSTIN must be high at this point or a hardware reset sequence will be triggered.
15.5
Pins after reset
After the reset sequence the different groups of pins of the ST10R272L are activated in
different ways depending on their function. Bus and control signals are activated
immediately after the reset sequence according to the configuration latched from PORT0, so
either external accesses can takes place or the external control signals are inactive. The
general purpose IO pins remain in input mode (high impedance) until reprogrammed via
software (see figure below). The RSTOUT pin remains active (low) until the end of the
initialization routine.
Figure 113 Software or watchdog reset
CPU Clock
RSTIN
Internal
Reset Configuration
INST #1
PORT 0
RSTOUT
ALE
512 CPU clock
RPD/Vpp
internally pulled low
Reset
Signal
Latching point of Port0
for system start-up configuration
200
µ
A Discharge
1)
2 CPU clock
3)
2)
RPD/Vpp >2V 3.3Voperation, >2.5V 5Voperation:
not entered.
Asynchronous Reset