5.12 How to connect the reset pin
The nRESET signal has input/output functionality and shall be driven in open-drain mode.
The signal has an internal 100K pull-up and a
100 Ohm series resistors,the maximum recommended capacitive load is about
100pF.
Figure 23
T
Delay
: driven low by SOM during the POR state
T
Reset
: driven low by user to force POR CPU pin
5.12.1 Input mode usage
The nRESET signal can be used to reset the module by driving it with an
open-drain
or with a simple button. If there are no special
requirements, the module is fully auto-sufficient in terms of reset sequence, so its nRESET signal can be left floating. No Pull-up resistor
is required on the carrier board; if a different pull-up resistor value (from the 100K on board of the module) is necessary, an additional
pull-up on the carrier can be placed with values greater than 10K Ohm.
5.12.2 Output mode usage
The nRESET signal can also be used to monitor POR phase of the module, or to apply the reset (POR only) to other devices on the
carrier. In this case, please take care to always respect limits imposed by maximum capacitive load and minimum additional pull-up.
WARNING: nReset is a POR signal only, therefore it may not be driven by the SOM during another CPU reset event (e.g.
WDOG reset).
D N :
4 0
