Hangzhou Tuya Inc.
NM1 Module Hardware Design Manual
https://www.tuya.com
Page 18 of 29
3.6.2 I
2
C Interface Electrical Parameters and Application
Figure 3- 5 Reference circuit
3.7 UART Interface
3.7.1 Pins
The NM1 module provides three UART interfaces. The primary serial interface can be used for firmware
upgrade. The default baud rate is 115.2 kbit/s, and the downloading baud rate is 921.6 kbit/s. You can use a log
viewing tool to view logs over the debugging serial interface to debug software.
Table 3- 7 UART interface signal definition
Pin No.
Signal Name
Function Description
17
RXD
Data receiving over the primary serial interface
18
TXD
Data transmission over the primary serial
interface
28
UART1_RXD
Data receiving over the auxiliary serial interface
29
UART1_TXD
Data transmission over the auxiliary serial
interface
38
RXD_DBG
Data receiving over the debugging serial
interface
39
TXD_DBG
Data transmission over the debugging serial
interface
3.7.2 UART Interface Electrical Parameters and Application
Figure 3- 6 Reference circuit
The level of the UART interfaces on the NM1 module is 1.8 V. If the application system level is 3.3 V, add a
level converter to the connection between the NM1 module and application system over the serial interface.
Figure 3- 7 shows the reference circuit with a level converter, UM3202.
