RWD_QT Datasheet, PDF (4/19 Pages) rfsolutions.ltd – The MicroRWD “QT” (Quad-Tag) version is a complete 125kHz reader solution for Hitag 1,

ib technology
Transmitted or Received data byte, 9600 baud, 8 bit, 1 stop, No parity (104uS per bit)
b0 b1 b2 b3 b4 b5 b6 b7 b8 b9
5v
1
0
TTL levels
0v
idle START
8 bit data
STOP idle
Repeated RWD polling cycle and serial communication BUSY protocol
RWD 5v
BUSY
0v
RWD 5v
RX
0v
RWD 5v
TX
0v
Ready to Receive
Busy
RWD cannot receive CMD or DATA
Ready to Receive
CMD/DATA
CMD/DATA
Host must Transmit CMD/DATA within 10mS of BUSY going low
Polling delay (100mS to 600mS)
100mS default
DATA
Host Driver software
Communication with the MicroRWD module is via the TTL level RS232 interface (9600
baud, 8 bit, 1 stop bit, no parity) and uses the CTS line for hardware handshaking. The
Windows applications (supplied with the Evaluation kit) can be used to communicate with the
module or the user can write their own application on a PC or a microcontroller. The
following basic communication algorithm should be used:-
Typical host computer “pseudo” driver code
if (Green LED ON (pin 2 = 0))
// Optional check for valid tag in field
{
if (CTS = 0)
// Wait for CTS = 0 (RWD ready to receive command / data)
{
// CTS times out after 10ms so command and all parameters must be sent with no-
// gaps otherwise CTS times out and goes HIGH.
// For example, send READ PAGE 1 (0x52 0x01)
SEND_CMD( ); // Sent command + parameters to RWD
// RWD sets CTS = 1 after last parameter received. RWD module enters low-
// power state during (programmable) polling delay then sends reply.
GET_REPLY( );
// Get Acknowledge byte + data
// Response to READ command is 0xC0 (no tag) or 0xD6 + four bytes of DATA.
}
}
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