Rainbow-electronics DS2890 Manual de usuario descargar pdf (Pagina 28)

DS2890

28 of 28

AC ELECTRICAL CHARACTERISTICS - OVERDRIVE 1-WIRE SPEED

2.8V £ V

PUP

£ 6.0V, -40°C £ T

£ +85°C

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Recovery Time t

REC

1µs

Reset High Time t

RSTH

48 µs

Reset Low Time t

RSTL

48 80 µs

Presence Detect High t

PDH

26µs

Presence Detect Low t

PDL

824µs

Notes:

1. The optimal sampling point for the master is as close as possible to the end time of the 2 ms t

RDV

period without exceeding t

RDV

. For the case of a Read-one time slot, this maximizes the amount of

time for the pull-up resistor to recover the line to a high level. For a Read-zero time slot it ensures

that a read will occur before the fastest 1-Wire device(s) release the line (t

RELEASE

= 0).

Read data setup time refers to the time the host must pull the 1-Wire bus low to read a bit. Data is

guaranteed to be valid within 1 µs of this falling edge.

An additional reset or communication sequence cannot begin until the reset high time (t

RSTH

) has

expired.

The reset low time (t

RSTL

) should be restricted to a maximum of 960 µs, to allow interrupt signaling,

otherwise, it could mask or conceal interrupt pulses.

CAPACITANCE TA = 25°C

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

1-Wire Pin 800 pF 1

Pin 10 pF

Resistor Terminals 10 pF

NOTE:

1. Capacitance on the 1-Wire pin could be 800 pF when power is first applied. If a 5 kW is used to pull

up the 1-Wire line to V

PUP

, the capacitance will not affect communications after a 5 ms charge time.

1 2 ... 23 24 25 26 27 28

Comentarios a estos manuales

Sin comentarios

Rainbow-electronics DS2890 Manual de usuario Pagina 28

Comentarios a estos manuales

Relacionado con productos y manuales para Panel De Control Rainbow-electronics DS2890