NXP CLRC663 Reader Module V1
PRODUCT OVERVIEW
- The CLRC663 Reader Module V1 is a robust, multi-protocol 13.56 MHz HF/NFC reader module designed for seamless integration into industrial and consumer electronics. Powered by the NXP CLRC66303 IC, it features a high-efficiency 4-turn PCB antenna and supports ISO/IEC 14443A/B, ISO/IEC 15693, and NFC protocols.
- The module offers ultimate flexibility with three selectable host interfaces (SPI, I2C, UART) and includes a “SAM-ready” port for high-security applications. To accelerate development, an open-source ESP32 Arduino library is provided.
INTERFACE CONFIGURATION (DIP SWITCH)
IMPORTANT: Configure the interface mode before applying power.
VISUAL ALIGNMENT METHOD (RECOMMENDED)
The module is designed for intuitive configuration using the on-board 2-position DIP switch and the PCB silkscreen.
- Look at the PCB: Next to the DIP switch, you will see printed labels for UART, I2C, and SPI.
- Action: Simply toggle the switches to visibly align with the printed mode label corresponding to your desired interface.
- Note: Ensure the switches are fully seated in the ON or OFF position as indicated by the diagram/text on the board.
LOGIC TABLE (TECHNICAL REFERENCE)
If the silkscreen is obstructed, use the following logic table to set the switches:
| Switch 1 | Switch 2 | Interface Mode |
| OFF | OFF | SPI (Default) |
| ON | OFF | UART |
| ON | ON | I2C |
| OFF | ON | Reserved (Do Not Use) |
Note: Please power cycle the module after changing the DIP switch settings for the changes to take effect.
TECHNICAL SPECIFICATIONS
MECHANICAL SPECIFICATIONS
- Dimensions: 40.02 mm x 42.36 mm
- Antenna Area: ~39 mm x 42 mm (Integrated 4-turn PCB coil)
- Mounting: 2x Mounting holes
- 3D Model DOWNLOAD
Chip-Level Pin Mapping
For developers using STM32, Linux, or other MCUs, the table below maps the module header pins directly to the NXP CLRC66303 chip pins. This allows you to use the standard NXP datasheet for register configuration.
| Module Pin | Function | CLRC66303 Pin Name | Pin # | Notes |
| 5V | Power Input | – | – | Input to onboard LDO, 3.0V~5.5V |
| PDOWN | Power Down | PDOWN | 21 | Active High (Hard Power Down) |
| MOSI / RX | SPI MOSI / UART RX | IF0 | 28 | Also I2C Address Bit 0 |
| MISO / TX | SPI MISO / UART TX | IF1 | 29 | Also I2C Address Bit 1 |
| SCK / SCL | SPI Clock | IF2 | 30 | I2C SCL line |
| NSS / SDA | SPI CS / I2C SDA | IF3 | 31 | I2C SDA line |
| IRQ | Interrupt | IRQ | 32 | Programmable Interrupt Output |
| 3V3 | Logic Ref / Output | TVDD / VDD | 8, 25 | Typical 3.3V (could be 2.5V~5.5V) Output from LDO / Logic Ref |
ELECTRICAL CHARACTERISTICS
| Parameter | Symbol | Min | Typ | Max | Unit |
| Supply Voltage | V_IN | 3.0 | 5.0 | 5.5 | V |
| Logic Voltage | V_IO | 2.5 | 3.3 | 5.5 | V |
| Typical Power Consumption | W active | – | 0.8 | – | W |
| Operating Temp | Top | -25 | – | +85 | °C |
INTEGRATION GUIDE
I2C ADDRESS CONFIGURATION
In I2C mode, the module acts as a slave. The 7-bit I2C address is configured via the logic states of：
- I2C_ADR1=MOSI/RX
- I2C_ADR2=MISO/TX
By Default, they are pulled to HIGH. So NC (not connected)/connecting to 3V3 means HIGH. To set to LOW or GND, there are two methods:
- Connect MOSI/RX or MISO/TX to GND.
- Bridge the soldering pads of I2C_ADR1 or I2C_ADR2 (this method will disable other mode like SPI or UART).
| I2C_ADR1 | I2C_ADR2 | 7-Bit I2C Address (Hex) | 8-Bit Read/Write |
| GND | GND | 0x28 | 0x50 / 0x51 |
| GND | NC | 0x29 | 0x52 / 0x53 |
| NC | GND | 0x2A | 0x54 / 0x55 |
| NC | NC | 0x2B (Default) | 0x56 / 0x57 |
SAM INTERFACE (SECURITY EXTENSION)
The module includes a dedicated SAM I2C PORT header for connecting an external Secure Access Module (e.g., NXP SAM AV2/AV3).
- Header Pinout: 3V3, SDA, SCL, GND.
- Internal Connection: Connected directly to CLRC66303 pins 23 (SCL) and 24 (SDA).
- Usage: Enables the reader to perform secure key storage and cryptographic operations (AES, 3DES) completely independent of the host MCU. Requires enabling “Host Interface” bits in the CLRC663 registers.
QUICK START
ESP32 + SPI MODE
STEP 1: WIRING
Connect the module to an ESP32 Development Board. Ensure DIP switches are set to SPI Mode (OFF/OFF).
| CLRC663 Pin | ESP32 Pin (VSPI) |
| 5V | 5V / VIN |
| GND | GND |
| PDOWN | GND (Keep Low for Active) |
| MOSI | GPIO 23 |
| MISO | GPIO 19 |
| SCK | GPIO 18 |
| NSS | GPIO 5 |
STEP 2: LIBRARY & CODE
- Download: Get the CLRC663_ELECHOUSE Library from GitHub.
- Install: In Arduino IDE, use Sketch -> Include Library -> Add .ZIP Library.
- Upload:
- Open File -> Examples -> CLRC663_ELECHOUSE -> Read UID.
- Select Board: ESP32 Dev Module.
- Upload and open Serial Monitor (115200 baud).
- Test: Place a MIFARE card near the antenna. The UID will appear in the monitor.
APPLICATION NOTES
- Supported Card Types (Library): ISO14443A (MIFARE Classic, Ultralight, NTAG), ISO15693 (ICODE SLIX).
- Installation:
- Avoid placing the antenna directly against metal surfaces.
- If mounting on metal is necessary, a ferrite sheet must be placed between the antenna and the metal surface to prevent detuning.
- Read Range: Typical 2.5cm – 8.5cm (Front side). Within 0~2cm, the reading is not stable at some distance points. If in your application you require reading in low distance, please attach the following ferrite sheet at the back side of the antenna:
This ferrite will benefit in the following ways: 1. Make stable reading between 0~7cm. 2.prevent interference from metals or circuit from the backside.
Documents / Resources
 | CLRC663 Reader Module V1 |
References
- User Manualmanual.tools