R
脳
5C338A
1.2 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 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
1
2
3
4
5
6
7
8
1
2
3
SCLK
SIO
A3
A2
A1
A0
C3
C2
C1
C0
D7
D6
D3
D2
D1
D0
Setting the address
pointer
Setting the transfer
format register
Writing data transfer /
Reading data transfer
Two types of data transfer formats are available for reading data transfer and writing data transfer each.
1.3 Writing Data Transfer Formats
1.3-1 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 transfer
format.
Example of 1-byte Writing Data Transfer
(For Writing Data to Addresses Fh and 7h)
CE
SIO
1 1 1 1 1 0 0 0
Specifying Fh Setting 8h
in the address in the transfer
pointer
format register
Data
Writing data
to address Fh
0 1 1 1 1 0 0 0
Specifying 7h Setting 8h
in the address in the transfer
pointer
format register
Data
Writing data
to address 7h
Data transfer from the host
Data transfer from the real-time clocks
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