Data Sheet

ManualsBrandsParallax ManualsRFIDRFID Read/Write Module - USB

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Forums: forums.parallax.com

Sales: sales@parallax.com

Technical: support@parallax.com

Office: (916) 624-8333

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Tech Support: (888) 997-8267

RFID Read/Write Module, Serial (#28440)

Designed in cooperation with Grand Idea Studio (www.grandideastudio.com), the Parallax Radio

Frequency Identification (RFID) Read/Write Module provides a low-cost solution to read and write passive

RFID transponder tags up to 3 inches away. The RFID transponder tags provide a unique serial number

and can store up to 116 bytes of user data, which can be password protected to allow only authorized

access.

The RFID Read/Write Module can be used in a wide variety of hobbyist and commercial applications,

including access control, user identification, robotics navigation, inventory tracking, payment systems, car

immobilization, and manufacturing automation.

Features

Low-cost method for reading and writing

passive, 125 kHz RFID transponder tags

y Up to 116 bytes of user data storage on a

single tag

y Optional security features prevent tag from

being read or written without password

y Bi-color LED for visual indication of status

Key Specifications

Power requirements: +5 VDC; < 10 mA idle,

approx. 100-200 mA active

y Communication: asynchronous serial 9600 bps,

(8N1); 5 V TTL-level, non-inverted

y Dimensions: 3.25 x 2.45 in (8.26 x 6.2 cm)

RFID Tag Compatibility

The RFID Read/Write Module works exclusively with

the EM Microelectronics EM4x50 1kbit R/W

transponder tags. A variety of different tag types and

styles exist, with the most popular ones made available

from Parallax.

Each tag contains a unique, read-only serial number (one of 2

, or 4,294,967,296 possible combinations)

and 116 bytes of user data area stored in a non-volatile EEPROM (Electrically Erasable Read Only

Memory). The user data area can be optionally secured with a 32-bit password to allow only authorized

read and write operations.

The RFID Read/Write Module provides, with a single command, legacy support for the EM

Microelectronics EM4100 read-only tags that are used with Parallax’s RFID Card Reader Serial (#28140)

and USB (#28340).

Summary of content (10 pages)

PAGE 1
Web Site: www.parallax.com Forums: forums.parallax.com Sales: sales@parallax.com Technical: support@parallax.com Office: (916) 624-8333 Fax: (916) 624-8003 Sales: (888) 512-1024 Tech Support: (888) 997-8267 RFID Read/Write Module, Serial (#28440) Designed in cooperation with Grand Idea Studio (www.grandideastudio.com), the Parallax Radio Frequency Identification (RFID) Read/Write Module provides a low-cost solution to read and write passive RFID transponder tags up to 3 inches away.
PAGE 2
Connections The RFID Read/Write Module easily interfaces to any host microcontroller using only four connections (VCC, SIN, SOUT, GND). Pin Pin Name Type Function 1 VCC P System power. +5V DC input. 2 SIN I Serial input from host. TTL-level interface, 9600 bps, 8 data bits, no parity, 1 stop bit. 3 SOUT O Serial output to host. TTL-level interface, 9600 bps, 8 data bits, no parity, 1 stop bit. System ground. Connect to power supply’s ground (GND) terminal.
PAGE 3
Usage There are many ways to use the RFID Read/Write Module and associated tags, but the three most common are as follows: 1) Read Only: Read the tag’s unique, non-changing 32-bit serial number 2) Read/Write: Read from and write up to 116 bytes of publicly accessible user data on the tag 3) Read/Write (Protected): Read from and write up to 116 bytes of password-protected user data on the tag. In this mode, you must enter the correct 32-bit password in order for read and write operations to be successful.
PAGE 4
Command Set 0x01: RFID_Read Read data from a specified address Input: Address location (1 byte), valid locations are 1-33 decimal Output: Status byte (1 byte) + data (4 bytes) Example: SEROUT RFID_TX, Baud, ["!RW", RFID_Read, ADDR_Serial] SERIN RFID_RX, Baud, [err, STR data\4] ' Read tag's serial number ' Get status byte & data bytes 0x02: RFID_Write Write data to a specified address Input: Address location (1 byte), valid locations are 3-31 decimal + data (4 bytes) Output: Status byte (1 byte) Example: '
PAGE 5
0x05: RFID_Protect Enable (lock) or disable (unlock) the tag’s password protection. Input: Mode (1 byte), 0x00 to unlock, 0x01 to lock Output: Status byte (1 byte) Example: SEROUT RFID_TX, Baud, ["!RW", RFID_Protect, 1] ' Lock the tag SERIN RFID_RX, Baud, [err] ' Get status byte Note: When the tag is locked, a successful login using the RFID_Login command is required before you can enable/disable password protection, change the tag’s password, or read/write to the tag.
PAGE 6
Error Checking The RFID Read/Write Module responds to each command with a single-byte status/error code in hexadecimal format followed by any returned data, if applicable. In most standard implementations, the user will repeatedly call the desired function until the ERR_OK status byte is returned, indicating that the function successfully completed with no errors.
PAGE 7
ADDR_Serial is a unique, read-only serial number with one of 232, or 4,294,967,296, possible values. It cannot be changed by the user. ADDR_DeviceID is a read-only value used to identify the specific tag family (for example, EM4150). The 32-bit value contains a family code, version code, reserved/unused bits, and a checksum value. It cannot be changed by the user. Further details of the EM4x50 tag can be found at: www.emmicroelectronic.com/Products.
PAGE 8
RFID Technology Overview Material in this section is based on information provided by the RFID Journal (www.rfidjournal.com). Radio Frequency Identification (RFID) is a generic term for non-contacting technologies that use radio waves to automatically identify people or objects. There are several methods of identification, but the most common is to store a unique serial number that identifies a person or object on a microchip that is attached to an antenna.
PAGE 9
' ==================================================================================== ' ' File...... rfid_rw_test.bs2 ' Purpose... System-level test code for the Parallax RFID Read/Write Module ' Author.... Joe Grand, Grand Idea Studio, Inc. [www.grandideastudio.com] ' E-mail.... support@parallax.com ' Updated... 15 Dec 2009 ' ' {$STAMP BS2} ' {$PBASIC 2.
PAGE 10
' Status/error return codes ERR_OK CON $01 ERR_LIW CON $02 ERR_NAK CON $03 ERR_NAK_OLDPW CON $04 ERR_NAK_NEWPW ERR_LIW_NEWPW CON CON $05 $06 ERR_PARITY CON $07 ' ' ' ' ' ' ' ' ' No errors Did not find a listen window Received a NAK, could be invalid command Received a NAK sending old password (RFID_SetPass), could be incorrect password Received a NAK sending new password (RFID_SetPass) Did not find a listen window after sending old password (RFID_SetPass) Parity error when reading data ' -----[ Vari