HCS473-SLQTP datasheet(21/68 Pages) MICROCHIP

21 / 68 page

 2002 Microchip Technology Inc.

Preliminary

DS40035C-page 19

HCS473

3.2.1

TRANSPONDER OPTIONS

The following HCS473 configuration options influence

the device behavior when in Transponder mode:

• Preamble length select (TPRLS)

• LF Demodulator (LFDEMOD)

• LF Baud rate select (LFBSL)

• Anticollision (ACOL)

• Proximity Activation (PXMA)

• Intelligent Damping (DAMP)

• LC response Enable (LCRSP)

• RF response Enable (RFRSP)

• Skip Field Acknowledge (SKIPACK)

The following sections describe these options in detail.

3.2.1.1

Transponder Preamble Length

Select (TPRLS)

Data responses through the DATA pin use the format

determined by the Encoder mode options, with one

exception/option to shorten the response time. The

response’s preamble can be reduced to 4 high pulses

by setting the transponder preamble length select

option. This only affects the responses as a result of

transponder communication (proximity activation trans-

missions included), not responses resulting from but-

ton input activations. The 4 high pulse short preamble

will be at the same duty cycle defined by the preamble

duty cycle Encoder mode option (PRD).

TABLE 3-2:

TRANSPONDER PREAMBLE

LENGTH SELECT (TPRLS)

3.2.1.2

LF Demodulator (LFDEMOD)

The HCS473 has a LF Demodulator mode useful for

debugging antenna hardware.

Enabling LFDEMOD limits the device to demodulator

only mode. After receiving an appropriate wake-up

sequence, the device enters a loop demodulating the

signal on the LC pins and outputting the resulting digital

representation on the LED pin. The HCS473 remains in

this mode until no edges are detected on the LC pins

for T

DEMOD, upon which it will return to Low-power

mode; requiring another wake-up sequence to further

demodulate data.

The demodulated signal on the LED pin is accurate to

within +/-10

µs of the signal on the LC pins. The injected

signal will have baud rate limitations based on the

HCS473’s internal filter charge and discharge times,

Section 3.2.6.

The filter times discussed in Section 3.2.6 will be easily

seen in Demodulator mode. The internal filter delay

may be isolated by communicating to the HCS473

inputting the digital signal into LCX and observing the

signal plus internal filter delays on the LED pin.

LFDEMOD options:

• Disabled - device functions normally

• Enabled - device demodulates signal on LC pins,

outputting digital result on the LED pin.

3.2.1.3

LF Baud Rate Select (LFBSL)

The LF Baud rate select option allows the user to adjust

the basic pulse width element (LF

TE) used for tran-

sponder communication.

LFBSL options:

• 100

µs LFTE

• 200

µs LFTE

• 400

µs LFTE

• 800

µs LFTE

All communication to and from the HCS473 through the

LC transponder pins will use the selected LF

TE. RF

acknowledges to LF communication, through the DATA

pin, will also use the selected LF

TE.

3.2.1.4

Anticollision (ACOL)

Multiple transponders in the same inductive field will

simultaneously

respond

inductive

commands.

Enabling

anticollision

prevents

multiple

HCS473

responses from 'colliding'. Hence the term ‘anticolli-

sion.’

When anticollision (ACOL) is enabled, the first com-

mand received after the device wakes must be either

the SELECT TRANSPONDER or ANTICOLLISION

OFFcommand before the HCS473 will respond to any

other command.

The ANTICOLLISION OFF command may be used to

temporarily bypass anticollision requirements for a sin-

gle communication sequence. It allows communication

with an anticollision enabled HCS473 if the VID and

TID are not known (perhaps during a learning

sequence). See Section 3.2.3.7 for further anticollision

off details.

The SELECT TRANSPONDER command allows the

addressing of and communication to an individual

HCS473, regardless if multiple devices are in the field

(Section 3.2.3.1).

Note:

The long preamble enable Encoder mode

option (LPRE) holds priority over the tran-

sponder preamble length option.

TPLS

LPRE

Description

Normal - 16 high pulses

Long - LPRL determines length

Short - 4 high pulses

Note:

Damping is disabled when in Demodulator

mode.

HCS473-SLQTP 数据表(PDF) 21 Page - Microchip Technology

HCS473-SLQTP 数据表(HTML) 21 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

数据表下载

链接网址

HCS473-SLQTP 数据表(PDF) 21 Page - Microchip Technology

HCS473-SLQTP 数据表(HTML) 21 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

数据表 下载

链接网址

数据表下载