MeiG_SLM550_Hardware Design Manual
MeiG Smart Technology Co., Ltd
4
2
/8
9
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 RESET Hardware Parameters
Pin
Description
Minimum
Typical
Maximu
m
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 17 External Capacitor Powering the RTC
Non-rechargeable battery powered:
Figure 18 Non-rechargeable battery to power the RTC
