Application, Figure 39, Figure 40 – Sierra Wireless WISMO218 User Manual
Page 79: Table 38, Reset commands, Push button ~reset, Gnd ~reset reset command
WA_DEV_W218_PTS_002
Rev 005
Page 79 of 109
Product Technical Specification &
Customer Design Guidelines
Application
If the « emergency » reset is used, it has to be driven by an open collector or an open drain output
(due to the internal pull-up resistor embedded into the WISMO218) as shown in the figure below.
GND
1
2
3
Push button
~RESET
Figure 39. Example of ~RESET Pin Connection with Push Button Configuration
GND
~RESET
Reset
command
T1
Rohm DTC144EE
Figure 40. Example of ~RESET Pin Connection with Transistor Configuration
An open collector or open drain transistor can be used to drive the ~RESET pin. If an open collector is
chosen, the recommended digital transistor to use for T1 is the DTC144EE from ROHM.
Table 38. Reset Commands
Reset Command
~RESET
Operating Mode
1
0
Reset activated
0
1
Reset inactive
Note:
It is recommended to add a varistor (AVL5M02200) on the ~RESET pin in order to enhance the ESD
immunity.