RV-3049 datasheet(50/65 Pages) MICROCRYSTAL

50 / 65 page

Micro Crystal

DTCXO Temperature Compensated Real Time Clock / Calendar Module

RV-3049

50/65

6.2.2.SPI INTERFACE READ / WRITE EXAMPLES

Serial bus read example (reading the Seconds register address 08h and Minutes register address 09h)

R / W

Page Address

Seconds data 11BCD

SCL

Minutes data 06BCD

SDO

address

counter

0Ah

09h

08h

SDI

Command Byte

08 Hex

Read

High Z

Data Byte

CE goes “High”:

transmission starts. SPI interface of the RV-3049 is enabled.

After sending Command Byte: the command byte sets the RV-3049 in “Read Mode”, the SDO pin

becomes active. The Page & Register address to 08h (Clock page;

Seconds register).

After reading Data Byte:

after transmission of every data byte, the register address is

automatically incremented.

CE goes “Low”:

transmission stops. SPI Interface of the RV-3049 is disabled, SDO

becomes High-Z.

Note:

In this example, the Seconds and Minutes registers are read. Pins SDI and SDO are not connected together; in this

configuration it is important that SDI pin is never left floating. It always must be driven either HIGH or LOW. If pin

SDI is left open, high IDD currents may result; short transition periods in the order of 200 ns will not cause any

problems.

RV-3049 Datasheet(PDF) 50 Page - MICORO CRYSTAL SWITZERLAND