ST10R272L - SYSTEM RESET
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15.5.1 RESET input pin
The RSTIN pin is a bi-directional pin. To reset the microcontroller, the RSTIN pin must be
held low for at least 2 CPU clock cycles for a warm (synchronous) hardware reset. After
RSTIN negation is internally resynchronized, a short transition period (approximately 6 CPU
clock cycles) elapses, then the microcontroller turns on a pull-down transistor on RSTIN pin
Figure 114 Reset input and output signals
RSTOUT
RSTIN
1)
1. Current bus cycle is completed or aborted.
2. Switches asynchronously with RSTIN, synchronously upon software or watchdog reset.
3. The reset condition ends here. The ST10R272L starts program execution.
4. Activation of the IO pins is controlled by software.
5. Execution of the EINIT instruction.
6. The shaded area designates the internal reset sequence, which starts after synchronization of RSTIN.
7. The RSTIN pin is not internally pulled low during asynchronous hardware reset.
Internal reset sequence
3)
Initialization
6)
Bus
Internal reset condition
Initialization
ALE
RD, WR
RSTIN
2)
IO
2
)
3)
5)
4)
6)
When the internal reset condition is prolonged by RSTIN, the activation of the output signals is delayed
until the end of the internal reset condition.
RSTIN internally driven low
7)
RSTIN internally driven low
External low pulse on RSTIN may end here
