R2043T-E2-F Datasheet, PDF (23/52 Pages) RICOH electronics devices division – 4-wire Serial Interface Real Time Clock IC

* R2043K (FFP12) is the discontinued product as of July, 2016.
R2043x
NO.EA-224-160701
(2) Data Transfer Formats
Data transfer is commenced in the low to high transition of the CE pin input and completed in its high to low transition.
Data transfer is conducted serially in multiple units of 1 byte (8 bits). The former 4 bits are used to specify in the
Address Pointer a head address with which data transfer is to be commenced from the host. The latter 4 bits are
used to select either reading data transfer or writing data transfer, and to set the Transfer Format Register to specify
an appropriate data transfer format. All data transfer formats are designed to transfer the most significant bit (MSB)
first.
CE
SCLK
12345678123
SI
A3 A2 A1 A0 C3 C2 C1 C0 D7 D6
D3 D2 D1 D0
Setting
Setting the Transfer
Writing data transfer
the Address Pointer
Format Register
SO
D7 D6
D3 D2 D1 D0
Reading data transfer
Two types of data transfer formats are available for reading data transfer and writing data transfer each.
• Writing Data Transfer Formats
(1) 1-byte Writing Data Transfer Format
The first type of writing data transfer format is designed to transfer 1-byte data at a time and can be selected by
specifying in the address pointer a head address with which writing data transfer is to be commenced and then writing
the setting of 8h to the transfer format register. This 1-byte writing data transfer can be completed by driving the
CE pin low or continued by specifying a new head address in the address pointer and setting the data transfer format.
Example of 1-byte Writing Data Transfer (For Writing Data to Addresses Fh and 7h)
CE
SI
11111000
Data
01111000
Data
SO
Specifying FhSetting 8h in
in the
the Transfer
Address
Format
Pointer
Register
Writing data to
address Fh
Specifying 7hSetting 8h in Writing data to
in the
the Transfer
address 7h
Address
Format
Pointer
Register
Data transfer from the host
Data transfer from the RTCs
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