原标题：ST ST25RU3993RAIN (UHF) RFID读卡器解决方案

　　ST公司的ST25RU3993RAIN® (UHF) RFID多协议读卡器,支持840-960 MHz UHF波段和ISO18000-62 & -63, ISO29143以及与GS1’s EPC UHF Gen2空中接口协议兼容.器件包括片上VCO和功率放大器,提供完整的RFID特性,包括密集读卡模式(DRM)功能,支持跳频,低电平发送编码,低电平译码,数据成帧和CRC检查.ST25RU3993工作电流非常低,使它非常适合用在手持设备和以电池为电源的设备如手机.工作电压3-3.6V,极低工作电压可低至2.7V,外设I/O电压从1.65V到5.5V,所支持的协议包括ISO 18000-6C (EPC Class1 Gen2),ISO 29143 (移动RFID空中接口),以及直接模式ISO 18000-6A/B,密集读卡模式(DRM)为M4和M8的250kHz和320kHz滤波器.器件集成了电源稳压器,支持跳频,采用ASK或PR-ASK调制,自动I/Q选择,用于标签跟踪的相位比特,有8位线性RSSI,工作温度-40℃ 到 85℃,采用48引脚QFN(7x7x0.9 mm)封装,标签读卡速率高达700*标签/秒(16位标签EPC长度).主要用在嵌入消费类电子/工业应用,手持读卡器,移动UHF RFID读卡器以及电池供电的固定读卡器.本文介绍了ST25RU3993主要特性,框图和基本UHF读卡器系统框图,发送和接收部分框图,以及评估板ST25RU3993-EVAL主要特性,电路图和PCB设计图.

　　The ST25RU3993 RAIN® (UHF) RFID reader device provides multi-protocol support for the 840-960 MHz UHF band compatible with ISO18000-62 & -63, ISO29143 and to GS1’s EPC UHF Gen2 air interface protocol. It includes an on-chip VCO and a power amplifier, and offers a complete set of RFID features including dense reader mode (DRM) functionality and support for frequency-hopping, low-level transmission coding, low-level decode, data framing and CRC checking.

　　The ST25RU3993 operates at very low-power, making it suitable for use in portable and battery-powered equipment such as mobile phones.

　　Packaged in a 7x7 mm QFN, the ST25RU3993 is able to deliver very high sensitivity and provides high immunity against the effects of antenna reflection and self-jamming. This is critical in mobile and embedded applications, in which antenna design is often compromised by cost or size constraints. High sensitivity enables the end-products to achieve their required read range while using a simpler and cheaper antenna, thus reducing overall system cost.

　　Thanks to its high level of integration, the ST25RU3993 requires only an external 8-bit microcontroller to create a complete RFID reader system, thus eliminating the need for a complex RFID co-processor.

　　ST25RU3993主要特性:

　　• Supply voltage range 3.0 to 3.6 V

　　– Limited operation possible down to 2.7 V

　　– Maximum PA supply voltage 4.3 V

　　– Peripheral I/O supply range 1.65 to 5.5 V

　　• Protocol support for:

　　– ISO 18000-6C (EPC Class1 Gen2)

　　– ISO 29143 (Air interface for mobile RFID)

　　– ISO 18000-6A/B through direct mode

　　• DRM: 250 kHz and 320 kHz filters for M4 and M8

　　• Integrated supply regulators

　　• Frequency hopping support

　　• ASK or PR-ASK modulation

　　• Automatic I/Q selection

　　• Phase bit for tag tracking with 8-bit linear RSSI

　　• Temperature range: -40℃ to 85℃

　　• 48-pin QFN (7x7x0.9 mm) package

　　• Tag read rates of up to 700* tags/s (16-bit tag EPC length)

　　ST25RU3993主要应用:

　　The ST25RU3993 device is ideally suited for:

　　• Embedded consumer/industrial applications with cost constraints such as beverage dispensing

　　• Hand-held readers

　　• Mobile UHF RFID readers

　　• Battery-powered stationary readers

　　图1.ST25RU3993框图

　　图2.ST25RU3993基本UHF读卡器系统框图

　　图3.ST25RU3993发送部分框图

　　图4.ST25RU3993接收部分框图

　　评估板ST25RU3993-EVAL

　　The ST25RU3993-EVAL board is a RAIN® RFID (UHF) reader system based on the ST25RU3993 integrated reader IC. The objective of the ST25RU3993-EVAL board is to provide engineers, students and technically interested people with a comprehensive RAIN RFID reader system, which allows evaluation of the properties and the feature set of the ST25RU3993. For this purpose the architecture of the ST25RU3993-EVAL board combines a high RF power, long-range reader and a low RF power, short-range RAIN RFID reader. In addition the ST25RU3993-EVAL board has been fitted with numerous easy to access test points and measurement possibilities.

　　图5.评估板ST25RU3993-EVAL外形图

　　The ST25RU3993-EVAL is controlled by a graphical user interface (GUI) running on a host PC through a USB/UART bridge (it requires a driver installation). The GUI can be found on www.st.com.

　　The ST25RU3993-EVAL is powered through a USB3.0 port to correctly operate the high RF power long-range configuration of the reader. If a USB3.0 port is not available, a USB2.0 Y-cable or an external power supply can be used to enable the long-range capabilities of the reader. If neither is available only the low RF power short-range reader configuration is available.

　　The ST25RU3993-EVAL provides two SMB (male) antenna connectors, which can be controlled via the GUI. To enable scanning for RAIN RFID transponders the user must connect the provided kit antenna or a suitable 50 Ω UHF antenna for the targeted frequency range.

　　The ST25RU3993-EVAL board supports frequency channels ranging from 840 to 960 MHz and Arm®-based devices.

　　评估板ST25RU3993-EVAL主要特性:

　　Based on the ST25RU3993 RAIN® (UHF) RFID reader IC

　　ISO/IEC 18000-63:2015 / Gen2V2

　　ISO/IEC 18000-62:2012

　　Two SW-controlled power amplifier (PA) options

　　External PA: 29 dBm max TX power

　　Internal PA: 18 dBm max TX power

　　Configurable TX power level

　　Power detector to monitor TX power

　　Carrier cancellation circuitry enabling pre- and re-tuning

　　Automatic / manual carrier cancellation

　　Differential RX input

　　Maximum sensitivity: -80 dBm

　　Maximum tag read rate: 700 tags/s (with 16-bit tag EPC length)

　　External reference: 20 MHz TCXO, clipped sine wave

　　External reference option: 20 MHz crystal

　　Frequency: 840 to 960 MHz

　　Adaptive / manual anti-collision slot handling

　　Continuous modulated RF output mode

　　Continuous wave RF output mode

　　Two antenna connectors: SMB (F)

　　Automatic / manual antenna port switching

　　Reflected power measurement

　　Carrier sense (LBT)

　　Transponder RSSI display

　　Direct command support

　　Transponder EPC read / write

　　Application start based on transponder reads

　　Generic custom transponder command tool

　　Store / recall reader configuration

　　Configurable register map

　　Host interface and supply

　　USB / UART bridge

　　USB receptacle: Micro, B-type

　　Main supply: 5 V USB (3.0)

　　MCU

　　STM32L476RGT6 (Arm® 32-bit Cortex®-M4)

　　64 MHz

　　128-Kbyte RAM

　　1-Mbyte Flash memory

　　SPI mode 1 (4 MHz)

　　Firmware programmable through USB / UART

　　SWD debug interface

　　LED Indicators

　　Power amplifier selection

　　Carrier cancellation tuning activity

　　Carrier cancellation tuning OK

　　OSC OK (20 MHz external reference)

　　PLL OK

　　RF ON

　　No tag response

　　Tag CRC error

　　Tag found

　　Active antenna port

　　Power amplifier option

　　BT OK (not installed)

　　Test points

　　In-circuit RF power levels and signals

　　RFID communication TX and RX

　　UART and SPI signal lines

　　UART_LOG for debug purposes

　　Control voltage of internal VCO

　　RF power detector output voltage

　　20 MHz reference signal

　　External PA BIAS voltage

　　LDO output voltages

　　LDOs: 0 Ω resistor for current consumption measurement

　　Main supply: jumper for current consumption measurement

　　Buttons

　　MCU reset

　　MCU boot mode

　　BT module reset button (optional)

　　Buzzer (optional)

　　Wireless interface (optional)

　　BT4.0 - SPP profile

　　JTAG interface: for BT module programming

　　BT module boot mode jumper (optional)

　　图6.评估板ST25RU3993-EVAL电路图(1)

　　图7.评估板ST25RU3993-EVAL电路图(2)