L99UDL01 datasheet(42/88 Pages) STMICROELECTRONICS

номер детали	L99UDL01

подробное описание детали	L99UDL01 Automotive Universal Door Lock IC

PDF	88 Pages

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производитель	STMICROELECTRONICS [STMicroelectronics]

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42 / 88 page

Serial communications

L99UDL01

42/88

DS12511 Rev 5

Serial communications

5.1

General information

The ST-SPI is a common serial peripheral interface protocol used in ST’s Automotive ASSP

devices. ST-SPI uses an in-frame response protocol for all communications providing for a

global status byte to be communicated for every SPI transmission.

5.1.1

Physical Layer

Figure 12. SPI pin description

5.2

Signal description

5.2.1

Chip Select Not (CSN)

The communication interface is deselected, when this input signal is logically high. A falling

edge on CSN enables and starts the communication while a rising edge finishes the

communication and the sent command is executed when a valid frame was sent. During

communication start and stop the Serial Clock (SCK) has to be logically low. The Serial

Data-Out (SDO) is in high impedance when CSN is high or a communication timeout was

detected (refer to CSN timeout).

5.2.2

Serial Clock (SCK)

This SCK provides the clock of the SPI. Data present at Serial Data Input (SDI) is latched on

the rising edge of Serial Clock (SCK) into the internal shift registers while on the falling edge

data from the internal shift registers are shifted out to Serial-Data-Out (SDO).

5.2.3

Serial Data Input (SDI)

This input is used to transfer data serially into the device. Data is latched on the rising edge

of Serial Clock (SCK).

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