Data Sheet

ISM14585-L35 Specification
DOC-DS-14585-201807-3.0
Confidential Inventek Systems
Page 23
9.4.2.1 POR TIMER CLOCK
The Power-On Reset timer is clocked by the RC32k clock. If the application disables the
RC32k, then the hardware takes care of enabling the RC32k clock when the POR
source (Reset pad or GPIO) is asserted. It should be noted that if POR is generated
from the Reset pad the RC32 will operate with the reset trimming value. If a GPIO is
used as POR source, the RC32 clock will be trimmed. The deviation between both
cases in terms of timing is expected to be minor.
9.4.2.2 RESET PAD
The Reset pad will produce a HW Reset if the pin active time is less than the
programmed value in the POR_TIMER_REG register and a Power-On Reset if it is
greater or equal the value. Reset pad is always Active High.
9.4.2.3 POR FROM GPIO
When a GPIO is used as a Power-on Reset source, the selected pin retains its
capability to act as GPIO. The POR_PIN_REG[PIN_SELECT] field holds the required
GPIO pin number. If the value of the PIN_SELECT field equals to 0 the POR over GPIO
functionality is disabled. The polarity of the pin can be configured by the
POR_PIN_REG [POR_POLARITY] bit where 0 means Active Low and 1 Active High.
9.4.2.4 POWER-ON RESET TIMING DIAGRAM
The operation of the Power-On Reset for both Reset pad and GPIO is depicted in
Figure 6.
Figure 6 Power-On Reset Timing Diagram