H1W200102 Datasheet, PDF (4/10 Pages) rfsolutions.ltd – Micro RWD H1 “Wiegand” Output Version

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The Micro RWD has two basic modes of operation:-
Antenna
Micro RWD
Chip Module
RS232
Serial
comms
Antenna
Micro RWD
Chip Module
Standalone mode with
Internal EEPROM holding
authorised tag codes for
acceptance
Host System
Remote mode (connected to a host computer or microcontroller) and Standalone mode.
1) Remote mode involves connecting to a host serial interface. This is where the stored
list of authorised identity codes can be empty, effectively authorising any HT1
transponder for subsequent read/write operations. A simple serial protocol allows a
host system to communicate with the Micro RWD in order to program new authorised
identity codes, change encryption seed code and perform read/write operations to the
tag itself.
2) Standalone mode is where the HT1 tag identity codes are checked against a stored list
of authorised codes. If an identity code is matched, the output drive and Green LED
are enabled. Effectively standalone mode occurs when there is no host system
communicating with the Micro RWD.
Supported transponder types
The Micro RWD is designed to communicate with Hitag1 transponders configured in R/W
Public mode. Setting the HT1 to any other configuration will render them inoperable with this
system. Note: Only the HT1 ICS30 02x Hitag silicon is fully supported for WRITE/
READ operations. The earlier HT1 ICS30 01x silicon (made obsolete early 1997) is only
supported for READ operations.
The operation of the Micro RWD and Hitag 1 transponders is described in more detail at the
end of this document.
The identification codes described in this text are regarded as the first four bytes (serial
number or page 0) of the tag memory array.
Serial Interface
This is a basic implementation of RS232. The Micro RWD does not support buffered
interrupt driven input so it must control a BUSY (CTS) line to inhibit communications from
the host when it is fully occupied with tag communication. It is assumed that the host (such
as a PC) can buffer received data.
Tx, Rx and RTS signals from the Micro RWD are all TTL level and can be converted to +/-
10v RS232 levels using an inverting level converter device such as the MAX202 (note the
inversion of the TTL levels).
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