AS3909 datasheet(66/77 Pages) AMSCO

66 / 77 page

AS3909/AS3910 – 66

ams Datasheet, Confidential: 2013-Oct [3-02]

A p pl i c at io n I n f o r m at i o n

Transparent Mode

The AS3909/10 framing supports the ISO-14443 standard.

Other standard and custom 13.56MHz RFID reader protocols

can be realized using the AS3909/10 AFE and framing

implemented in the external microcontroller.

After sending the direct command Transparent Mode the

external microcontroller directly controls the transmission

modulator and gets the

Receiver output (control logic becomes “transparent”).

The Transparent Mode is entered on falling edge of signal SEN

after sending the command Transparent Mode and is

maintained as long as the signal SEN is kept low. Before sending

the direct command Transparent Mode the Transmitter and

Receiver have to be turned on, the AFE have to be configured

properly.

While the AS3909/10 is in the Transparent Mode the AFE is

controlled directly through SPI interface:

• The Transmitter modulation is controlled by pin SDATAI

(high is modulator on)

• Signal rx_on is controlled by pin SCLK (high enables RSSI

and AGC)

• The Receiver output is sent to pin SDATAO

By controlling the rx_on advanced Receiver features like the

RSSI and AGC can be used.

Configuration bits related to the ISO mode, framing and FIFO

are of course meaningless in Transparent Mode, all other

configuration bits are respected.

For communication reader to transponder the OOK and AM

modulation are supported. Type of the modulation is defined

by writing the bit 6 (am) of the Configuration Register 5 (#05).

The direct command Calibrate Modulation Depth supports

modulation depths up to 30%, by writing the AM Modulated

Level Definition Register (#12) also definition of deeper am

modulation is possible.

The Receiver filters support the subcarrier frequencies from 212

kHz to 848 kHz. The filter characteristics are defined by writing

the bits fs2 to fs0 in the Receiver Configuration Register (#6).

AS3909 데이터시트(PDF) 66 Page - ams AG