L9963T datasheet(24/45 Pages) STMICROELECTRONICS

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3.3.8

Electrical parameters - FSM

All parameters are tested and guaranteed in the following conditions, unless otherwise specified: 4.5 V ≤ VVDD ≤

5.5 V ; -40 °C < Tj < 125 °C

Table 17. FSM electrical parameters

Symbol

Parameters

Test conditions

Min Typ Max Unit

TFIRST_POWERUP

Time needed to perform first power up sequence (refer

to L9963T FSM)

1.25 ms

TWAKEUP

Time from wake up detection to ISOL-ISOP ready to

transmit

1.06 ms

TGO2SLP

Time needed to perform a power down sequence (refer

to L9963T FSM)

400

μs

NMIN_ISO_WUP_EDGES -

Guaranteed by

SCAN

TWAKEUP_TIMEOUT_ISO

Timeout of the pulse counter for wake up detection

(isolated SPI)

Tested by SCAN

150

630

μs

3.4

Serial communication interface

L9963T integrates two communication interfaces:

•

SPI interface can be used for the local data exchange with a master MCU (NSLAVE = 0) or with a generic

slave IC (NSLAVE = 1). SPI electrical parameters are listed in Table 21.

•

Isolated SPI interface can be used for global/local isolated communication with another L9963T

or with an ISOLine compatible device (such as L9963). ISOLine electrical parameters are listed in

Section 3.4.4.1.1.1 Electrical parameters - ISO receiver and Section 3.4.4.1.2.1 Electrical parameters

- ISO transmitter.

The throughputs on the 2 communication interfaces are different and not related. The two interfaces can work at

the same time.

3.4.1

Frame input/output management

L9963T manages the asynchronicity and the different throughputs between SPI and ISOline (ISOline usually

slower than SPI). It does it by buffering the incoming frames into queues then propagating them outside when

possible.

Queues are managed according to their status (empty, not empty, full) and according to device I/Os.

L9963T mechanisms are frame-based but the device totally neglects frame’s contents, thus not performing any

protocol check.

The allowed frame length in terms of bits is not fixed, it can vary in the NBIT_PER_FRAME_RANGE range, on a frame

by frame basis.

3.4.1.1

Input from ISOline interface

The device detects the end of an incoming frame if no valid bit has been received for at least ISO_RX_EOF.

When the end of frame is detected, the frame is transferred into the RX queue as a single frame.

Being ISO_TX_IF greater than ISO_RX_EOF, a correct frame handling is guaranteed by design.

After the end of frame event, any new valid ISOLine bit must be considered as the first one of a new frame.

Any frame whose bit length is in the allowed NBIT_PER_FRAME_RANGE is stored into the RX queue.

The RX queue size is MAX_RX_QUEUE_FRAME_NUMBER frame. In case of FIFO full, any incoming frame

replaces the last received one.

3.4.1.2

Input from SPI interface

When the device is configured as SPI Slave (NSLAVE = 0), it detects the start of frame sensing the assertion of

NCS (chip select) and the end of frame sensing NCS deassertion.

L9963T

Serial communication interface

DS13590 - Rev 4

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