Use Manual

2.2 41pin QFN Pin definition
The pin definition is as below, and its pin number refers to item 2.1.
No Name Type Description
1NCI/O Nofunction
2 PB2 I/O GPIO PIN
3NCI/O Nofunction
4NCI/O
5NCI/O
6NCI/O
7NCI/O
8 PA2 I/O GPIO PIN
9 PA1 I/O GPIO PIN
10 VBAT I/O
MCU operating voltage input (power supply for RTC,
external clock, 32 kHz oscillator and backup registers
(through power switch) when VDD is not present.)
11 NC I/O No function
12 PA3 I/O GPIO PIN
13 MICRO_RST_N I/O MCU Reset
14 WAKE_UP I/O Wake up
15 NC I/O No function
16 PC13 I/O GPIO PIN
17 I2C2_SCL（PB10） I/O I2C_SCL
18 I2C2_SDA（PB9） I/O I2C_SDA
19 I2C2_SMBA I/O I2C_SMBA
20 GND — Ground
21 GND — Ground
22 JTAG_TDO I/O JTAG_TDO
23 JTAG_TDI I/O JTAG_TDI
24 JTAG_TRST_L I/O JTAG_TRST_L
25 JTAG_TCK I/O JTAG_TCK
26 JTAG_TMS I/O JTAG_TMS
27 USART1_RTS I/O HCI UARTrequest to send
28 NC I/O No function
29 USART1_RX I/O HCI UART receive input
30 USART1_TX I/O HCI UART transmit output
31 PB8 I/O GPIO PIN
32 NC I/O No function
33 PB13 I/O GPIO PIN
34 PA5 I/O GPIO PIN
35 USART1_CTS I/O HCI UARTclear to send
36 PB1 I/O GPIO PIN
37 PB0 I/O GPIO PIN
38 PA4 I/O GPIO PIN
39 VDD_3V3 V Power supply input
40 VDD_3V3 V Power supply input
41 ANT O RF OUTPUT(option)