MLX90121

13.56MHz RFID Transceiver

3901090121

Page 10 of 26

Data Sheet

Rev. 007

Jan-2008

MODE

DIN

CK

Address

Data

RTB

MSB

MSB

LSB

LSB

After sending address and data, the MODE line is asserted high and the chip is ready to receive the next

register configuration.

Signal

Assign

MODE

RTB

DIN

CK

0

0

4-bit Address + 8-bit Data

12 clock pulses

DOUT

DSYNC

x

x

Notes

1.

If a register does not contain eight bits, write ‘0’ in the unused bit.

2.

When MODE is asserted high, the chip is in communication mode. If the encoder is disabled (by

default), DIN has to be kept at ‘1’ to avoid any modulation on the antenna.

3.

In case of successive registers writings, it is mandatory to have MODE asserted high for at least

µs in between each access, as shown in the following diagram.

MODE

CK

Writing 1

Writing 2

Tmw

11.3. Communication Modes

11.3.1. Transmission

11.3.1.a. Analog Setup

For the transmission, the modulation depth has to be chosen. This is done by the TModIndex bit of the

AnalogConfig register, which selects the modulation index: 10% or 100%.

The modulation index can be further tuned by means of the external RMOD resistor.