SIM Tech SimCom SIM340, Проектирование аппаратного обеспечения

Страница: 29 / 69

SIM340 Hardware Design
If the voltage ≤ 3.4V, the following URC will be presented:
UNDER-VOLTAGE POWER DOWN
If the voltage ≥ 4.6V, the following URC will be presented:
OVER-VOLTAGE POWER DOWN
After this moment, no further more AT commands can be executed. The module logs off from
network and enters POWER DOWN mode, and only the RTC is still active. POWER DOWN can
also be indicated by VDD_EXT pin, which is a low level voltage in this mode.
3.4.2.4 Over-temperature or under-temperature automatic shutdown
The module will constantly monitor the temperature of the module, if the temperature ≥ 80 ℃ ,
the following URC will be presented:
+CMTE:1
If the temperature
≤
-30
℃
, the following URC will be presented:
+CMTE:-1
The uncritical temperature range is -35
℃
to 85
℃
. If the temperature
≥
85
℃ or ≤
-35
℃
, the
module will be automatic shutdown soon.
If the temperature
≥ 85 ℃ , the following URC will be presented:
+CMTE:2
If the temperature ≤ -35 ℃ , the following URC will be presented:
+CMTE:-2
After this moment, the AT commands can’t be executed. The module logs off from network and
enters POWER DOWN mode, and only the RTC is still active. POWER DOWN can also be
indicated by VDD_EXT pin, which is a low level voltage in this mode.
To monitor the temperature, you can use the “AT+CMTE” command to read the temperature when
the module is power on.
For details please refer to
document [1]
3.4.3 Restart SIM340 using the PWRKEY pin
You can restart SIM340 by driving the PWRKEY to a low level voltage for some time, the same
as turn on SIM340 using the PWRKEY pin. Before restarting the SIM340, you need delay at least
500ms from detecting the VDD_EXT low level on. The restarting scenario illustrates as the
SIM340_HD_V3.09 18.03.2009
29