AK7735EQ Datasheet, PDF (87/142 Pages) Asahi Kasei Microsystems – Dual DSP with 4chADC + 4chDAC + 4chSRC

[AK7735]
1-5. The First Byte
The First Byte, which includes the Slave-address, is input after the Start condition is set, and a target IC
device that will be accessed on the bus is selected by the Slave-address.
When the Slave-address is inputted, an external device that has the identical device address generates
an acknowledgement and instructions are then executed. The 8^th bit of the First Byte (lowest bit) is
allocated as the R/W Bit. When the R/W Bit is “1”, the read instruction is executed, and when it is “0”, the
write instruction is executed.
The Slave-address of the AK7735 is set by the CSN pin.
CSN pin = “H”
0
0
1
1
0
0
0
R/W
CSN pin = “L”
0
0
1
1
1
0
0
R/W
Figure 65. First Byte Configuration (I²C)
Note
* 70. In this document, there is a case that describes a “Write Slave-address assignment” when both
address bits match and a Slave-address at R/W Bit = “0” is received. There is a case that
describes “Read Slave-address assignment” when both address bits matches and a
Slave-address at R/W Bit = “1” is received.
1-6. The Second and Succeeding Bytes
The data format of the second and succeeding bytes of the AK7735 Transfer / Receive Serial data
(command code, address and data in microcontroller interface format) on the I²C BUS are all configured
with a multiple of 8-bits. When transferring or receiving those data on the I²C BUS, they are divided into
an 8-bit data stream segment and they are transferred / received with the MSB side data first with an
acknowledgement in-between.
Example)
When transferring / receiving A1B2C3 (hex) 24-bit serial data in microprocessor interface format:
(1) Microcomputer format
(1) I²C format
A1
B2
C3
A1
B2
C3
A
A
24BIT
8BIT
8BIT
8BIT
A …Acknowledge
Figure 66. Division of Data (I²C)
Note
* 71. In this document, there is a case that describes a write instruction command code which is received
at the second byte as “Write Command”. There is a case that describes a read instruction
command code which is received at the second byte as “Read Command”.
016014707-E-00
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2016/12