User's Manual

Table of Contents
1. Key Features ...............................1
2. Pinout ..................................2
2.1 Power, Ground and Reset Pads ........................2
2.2 Peripherals and GPIOs ...........................3
2.2.1 Peripheral and GPIO pads .........................3
2.2.2 Peripheral Locations ...........................4
2.2.3 GPIO Port Pins .............................6
2.2.4 GPIO Input and Output Modes .......................6
2.2.5 Interrupt Pins .............................6
2.3 Debug and RF Test Pads ..........................6
3. Interfaces.................................8
3.1 Host Interfaces .............................8
3.1.1 UART ................................8
3.1.2 SPI .................................9
3.1.3 USB ................................10
3.2 Peripheral Interfaces and Functions ......................11
3.2.1 USART (UART/SPI) ...........................12
3.2.2 I
2
C .................................12
3.2.3 Timer / PWM .............................12
3.2.4 Analog to Digital Converter (ADC) ......................12
3.3 Firmware Update and RF Test Interfaces.....................12
3.3.1 ARM Serial Wire Debug (SWD) .......................13
3.3.2 Device Firmware Upgrade (DFU) .......................13
3.3.3 RF Test Interface ............................13
3.3.4 Reference Schematic for SWD Debug and RF Test Interfaces .............13
3.4 Real Time Counter (RTC) ..........................13
4. Module Software ............................. 14
5. Hardware Design Guidelines ........................ 16
5.1 Power Supply Requirements .........................16
5.2 PCB Design Guidelines ..........................16
5.3 Antenna Design Guidelines .........................17
5.3.1 Effect of Plastic and Metal Materials ......................17
5.3.2 Locating the Module Close to Human Body ...................18
6. Electrical Characteristics .......................... 19
6.1 Absolute Maximum Ratings .........................19
6.2 Recommended Operating Conditions ......................19
6.3 Input/Output Terminal Characteristics ......................19
6.4 Power-on Reset .............................20
6.5 Analog Digital Converter (ADC) ........................20
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