LRI512 datasheet(26/54 Pages) STMICROELECTRONICS

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LRI512

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TIMING DEFINITION

t1: LRI512 Response Delay

t1 is as defined in Table 19.

Upon detection of the rising edge of the EOF re-

ceived from the VCD, the LRI512 wait for a time

equal to

t1(typ) = 4352/fC (see Table 59)

before starting to transmit its response to a VCD

request or switch to the next slot when in an inven-

tory process.

The EOF is defined in page 7.

t2: VCD New Request Delay

t2 is the time after which the VCD may send an

EOF to switch to the next slot when one or more

LRI512 responses have been received during an

inventory command. It starts from the reception of

the EOF received from the LRI512s.

The EOF sent by the VCD may be either 10% or

100% modulated independent of the modulation

index used for transmitting the VCD request to the

LRI512.

t2 is also the time after which the VCD may send a

new request to the LRI512 as described in Figure

29., LRI512 Protocol Timing, on page 16.

t2(min) = 4192/fC (see Table 59)

t3: VCD New Request Delay when No LRI512

Response

t3 is the time after which the VCD may send an

EOF to switch to the next slot when no LRI512 re-

sponse has been received.

The EOF sent by the VCD may be either 10% or

100% modulated independent of the modulation

index used for transmitting the VCD request to the

LRI512.

From the time the VCD has generated the rising

edge of an EOF:

– If this EOF is 100% modulated, the VCD shall

wait a time at least equal to t3minimum before

sending a subsequent EOF.

– If this EOF is 10% modulated, the VCD shall

wait a time at least equal to the sum of t3minimum

+ the nominal response time of a LRI512, which

depend on the LRI512 data rate and subcarrier

modulation mode before sending a subsequent

EOF.

Table 19. Timing Values (see Table 59)

Note: 1.

tSOF is the duration for the LRI512 to transmit an SOF to

the VCD.

tSOF is dependant on the current data rate:

High data rate or Low data rate.

t1(max) does not apply for write alike requests. Timing

conditions for write alike requests are defined in the com-

mand description.

3. The tolerance of specific timings is ± 32/fC.

Min.

Nominal

Max.

t1(min)

t1(typ)

t1(max)

t2(min)

——

t1(max) + tSOF

(notes1,2)

——

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