CLRC63201T View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'CLRC63201T' PDF : 127 Pages View PDF
NXP Semiconductors
CLRC632
Standard multi-protocol reader solution
9.5.2 Using the timer unit functions
9.5.2.1 Time-out and WatchDog counters
After starting the timer using TReloadValue[7:0], the timer unit decrements the TimerValue
register beginning with a given start event. If a given stop event occurs, such as a bit
being received from the card, the timer unit stops without generating an interrupt.
If a stop event does not occur, such as the card not answering within the expected time,
the timer unit decrements down to zero and generates a timer interrupt request. This
signals to the microprocessor the expected event has not occurred within the given time
(tTimer).
9.5.2.2 Stopwatch
The time (tTimer) between a start and stop event is measured by the microprocessor using
the timer unit. Setting the TReloadValue register triggers the timer which in turn, starts to
decrement. If the defined stop event occurs, the timer stops. The time between start and
stop is calculated by the microprocessor using Equation 5, when the timer does not
decrement down to zero.
t = TReLoadvalue – TimerValue tTimer
(5)
9.5.2.3 Programmable one shot timer and periodic trigger
Programmable one shot timer: The microprocessor starts the timer unit and waits for
the timer interrupt. The interrupt occurs after the time specified by tTimer.
Periodic trigger: If the microprocessor sets the TAutoRestart bit, it generates an interrupt
request after every tTimer cycle.
9.5.3 Timer unit registers
Table 24 shows the related flags of the timer unit in alphabetical order.
Table 24. Associated timer unit registers and flags
Flags
Register name
TAutoRestart
TimerClock
TimerValue[7:0]
TimerValue
TReloadValue[7:0]
TimerReload
TPreScaler[4:0]
TimerClock
TRunning
SecondaryStatus
TStartNow
Control
TStartTxBegin
TimerControl
TStartTxEnd
TimerControl
TStopNow
Control
TStopRxBegin
TimerControl
TStopRxEnd
TimerControl
Bit
5
7 to 0
7 to 0
4 to 0
7
1
0
1
2
2
3
Register address
2Ah
0Ch
2Ch
2Ah
05h
09h
2Bh
2Bh
09h
2Bh
2Bh
CLRC632
Product data sheet
COMPANY PUBLIC
All information provided in this document is subject to legal disclaimers.
Rev. 3.7 — 27 February 2014
073937
© NXP Semiconductors N.V. 2014. All rights reserved.
27 of 127
Share Link: 
