User's Manual

720 Hardware User Guide

Components:

R2/R4: 2K-10K. The greater the UART baud rate is, the lower the R2 value is.

R1/R3: 4.7K-10K The greater the UART baud rate is, the lower the R3 value is.

Q1: MMBT3904 or MMBT2222 High-speed transistor is better.

MCU_UTXD and MCU_URXD are respectively the TX and RX ports of the MCU while TXD and

RXD are respectively the TX and RX ports of the module.

Voltage at VCC_IO is the voltage at the UART of the MCU while voltage at VDDIO_1V8 is the

voltage at the UART of the module.

2.6.2 ADC

N720 provides two ADC channels, and the input voltage ranges from 0.1 to 1.7V. ADC pin

supports highest precision of 16-bit and it can be used for temperature and other check. If you

apply this pin to SIM card temperature check on electric terminals, refer to Neoway GPRS

Module ADC User Guide.

2.6.3 NET_LIGHT

NET_LIGHT can output 1.8 V high level and is forbidden to be used to drive the LED indicator.

Users can drive the LED with a transistor instead, as shown in Figure 2-18.

Figure 2-19 LED indicator driven by transistor