RV-3049 datasheet(47/65 Pages) MICROCRYSTAL

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Micro Crystal

DTCXO Temperature Compensated Real Time Clock / Calendar Module

RV-3049

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6. SPI INTERFACE

SPI Interface connects Master and one or multiple Slave devices. Data transfer to and from the devices is made via

a 4-wire (3-wire) SPI bus. The four lines are: Chip Enable (CE), Serial-CLock (SCL), Serial-Data-Output (SDO) and

Serial-Data-Input (SDI).

The chip enable signal CE is used to enable the considered device and to identify the transmitted data.

The data lines for input and output are split into two separate lines. However, the Data-Input SDI and Data-Output

SDO lines can be connected together to facilitate a bidirectional data bus in single wire mode.

6.1. SPI INTERFACE SYSTEM CONFIGURATION

SPI Serial Interface

Symbol

Function

Description

SCL

Serial Clock Input

Serial Clock Input pin; this Input may float when CE is LOW (inactive), may be higher than VDD

SDI

Serial Data Input

Serial Data Input pin; this Input may float when CE is LOW (inactive), may be higher than VDD; input

data is sampled on the rising edge of SCL

SDO

Serial Data Output

Serial Data Output pin; push-pull drives from VSS to VDD; high-impedance when not driving; can be

connected to SDI for single-wire data line, output data is changed on the falling edge of SCL

Chip Enable input

Chip Enable input active HIGH but may not be wired permanently HIGH, with internal 100 kΏ pull-down

resistor, when LOW the interface is reset.

SDI / SDO Configurations

Note:

The data lines for input and output are split into two separate lines, however, the Data-Input SDI and Data-Output

SDO lines can be connected together to facilitate a bidirectional data bus in single wire mode.

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