MeiG Smart product technical information
SLM500
Hardware Design Guide
Page 34
When the pin is high, the voltage is typically 1.8V. Therefore, for users with a level of 3V or
3.3V, it is not possible to directly use the GPIO of the MCU to drive the pin. An isolation
circuit is required. The hardware parameters of the RESET(225) can refer to the following
table:
Table
4.1
：
RESET Hardware Parameters
Pin
Description
Minimum
Typical
Maximum
Unit
RESET
_N
Input high level
1
-
-
V
Input low level
-
-
0.65
V
Pull down effective time
500
-
ms
4.3. VCOIN Power
When VBAT is disconnected, the user needs to save the real-time clock. The VCOIN pin
cannot be left floating. It should be connected to a large capacitor or battery. When external
capacitor is connected, the recommended value is 100uF, and the real-time clock can be kept
for 1 minute. The reference design circuit is used when the RTC power supply uses an external
large capacitor or battery to power the RTC inside the module:
Figure 4.10
：
External Capacitor Powering the RTC
Non-rechargeable battery powered:
Figure 4.11
：
Non-rechargeable battery to power the RTC
