Neoway N21 Series User Manual

N21
Hardware User Guide
Copyright © Neoway Technology Co., Ltd. All rights reserved.
18
Figure 3-14 Recommended level shifting circuit 3
C1
C2
220pF
UART_RXD
10 kΩ
10 kΩ
4.7 kΩ
VDDIO_2P8
4.7 kΩ
220pF
47 kΩ
4.7 kΩ
Q1
Q2
MCU_TXD
R4
R1
R6
R5
R2
R3
C1
C2
220pF
UART_TXD
10 kΩ
R2 47
kΩ
4.7 kΩ
VDDIO_2P8
2.2 kΩ
220pF
47 kΩ
4.7 kΩ
Q1
Q2
MCU_RXD
VCC_IO
R4
R1
R5
R6
R3
Q1, Q2: MMBT3904 or MMBT2222. High-speed transistor is better.
MCU_TXD and MCU_RXD are respectively the TX and RX of the MCU while UART_TXD and
UART_RXD are respectively the TX and RX of the module. VCC_IO is the IO voltage of the MCU.
3.3.2 USIM
Signal
Pin
I/O
Function
Remarks
USIM_VCC
9
PO
USIM power
Compatible with 1.8 V/3 V USIM card
USIM_DATA
6
DIO
USIM card data IO
A 10 kΩ resistor is required between
USIM_VCC and USIM_DATA.
USIM_CLK
7
DO
USIM clock

Neoway N21 Series Specifications

General

Brand	Neoway
Model	N21 Series
Category	Control Unit
Language	English