LRI64 datasheet(19/38 Pages) STMICROELECTRONICS

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LRI64

TIMING DEFINITIONS

Figure 22. shows three specific delay times: t1, t2

and t3. All of them have a minimum value, speci-

fied in Table 14.. The t1 parameter also has a max-

imum and a typical value specified in Table 14., as

summarized in Table 8.

Table 8. Timing Values

Note: 1.

tSOF is the duration for the LRI64 to transmit an SOF to

the VCD.

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.

LRI64 Response Delay, t1

Upon detection of the rising edge of the EOF re-

ceived from the VCD, the LRI64 waits for a time

equal to

t1(typ) = 4352 / fC

before starting to transmit its response to a VCD

request, or switching to the next slot when in an in-

ventory process.

VCD New Request Delay, t2

t2 is the time after which the VCD may send an

EOF to switch to the next slot when one or more

LRI64 responses have been received during an in-

ventory command. It starts from the reception of

the EOF received from the LRI64 devices.

The EOF sent by the VCD is 10% modulated, in-

dependent of the modulation index used for trans-

mitting the VCD request to the LRI64.

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

new request to the LRI64 as described in Figure

19.

t2(min) = 4192 / fC

VCD New Request Delay when there is No

LRI64 Response, t3

t3 is the time after which the VCD may send an

EOF to switch to the next slot when no LRI64 re-

sponse has been received.

The EOF sent by the VCD is 10% modulated, in-

dependent of the modulation index used for trans-

mitting the VCD request to the LRI64.

From the time the VCD has generated the rising

edge of an EOF:

–

The VCD waits for a time at least equal to the

sum of t3(min) and the typical response time of

an LRI64, which depends on the data rate and

subcarrier modulation mode, before sending a

subsequent EOF.

Min.

Typ.

Max.

t1(min)

t1(typ) = 4352 / fC

t1(max)

t2(min) = 4192 / fC

——

t1(max) + tSOF

(see notes1,2)

——

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