CLRC663 datasheet(81/177 Pages) NXP

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NXP Semiconductors

CLRC663

High performance multi-protocol NFC frontend CLRC663 and CLRC663 plus

Bit

Symbol

Description

7 to 0

T3Counter

ValLo

Low byte current counter value of Timer3.

This value shall not be read out during reception.

Table 120. T3CounterValLo bits

9.7.2.20 T4Control

The wake-up timer T4 activates the system after a given time. If enabled, it can start the low-power card

detection function.

Bit

Symbol

T4Running

T4Start

StopNow

T4Auto

Trimm

T4Auto

LPCD

T4Auto

Restart

T4AutoWakeUp

T4Clk

Access

rights

r/w

Table 121. T4Control register (address 23h)

Bit

Symbol

Description

T4Running

Shows if the timer T4 is running. If the bit T4StartStopNow is set, this bit and the timer

T4 can be started/stopped.

T4Start

StopNow

if set, the bit T4Running can be changed.

T4AutoTrimm

If set to one, the timer activates an LFO trimming procedure when it underflows. For

the T4AutoTrimm function, at least one timer (T0 to T3) has to be configured properly

for trimming (T3 is not allowed if T4AutoLPCD is set in parallel).

T4AutoLPCD

If set to one, the timer activates a low-power card detection sequence. If a card is

detected an interrupt request is raised and the system remains active if enabled. If no

card is detected the CLRC663 enters the Power down mode if enabled. The timer is

automatically restarted (no gap). Timer 3 is used to specify the time where the RF field

is enabled to check if a card is present. Therefore you may not use Timer 3 for T4Auto

Trimm in parallel.

T4AutoRestart

Set to logic 1, the timer automatically restarts its countdown from T4ReloadValue, after

the counter value has reached the value zero. Set to logic 0 the timer decrements to

zero and stops. The bit Timer4IRQ is set to logic 1 at timer underflow.

T4AutoWakeUp

If set, the CLRC663 wakes up automatically, when the timer T4 has an underflow. This

bit has to be set if the IC should enter the Power down mode after T4AutoTrimm and/

or T4AutoLPCD is finished and no card has been detected. If the IC should stay active

after one of these procedures, this bit has to be set to 0.

1 to 0

T4Clk

00b - the timer input clock is the LFO clock

01b - the timer input clock is the LFO clock/8

10b - the timer input clock is the LFO clock/16

11b - the timer input clock is the LFO clock/32

Table 122. T4Control bits

9.7.2.21 T4ReloadHi

High byte of the reload value of the 16-bit timer 4.

CLRC663

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 5.3 — 3 January 2024

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