AK7755EN_16 Datasheet, PDF (81/109 Pages) Asahi Kasei Microsystems – DSP with Mono ADC Stereo CODEC + Mic/Lineout Amp

[AK7755]
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. The Slave-address is configured
with the upper 7-bits. When the I2CSEL pin = “H” and the EXTEEP pin = “L”, data of the upper 6-bits is
“001100”. The next 1 bit is the address bits that select the desired IC which are set by the CAD pin. The
slave address will be “0011000” when the I2CSEL pin =“H” and the EXTEEP pin = “L”. However, the
CAD pin should be set to “L” if the MATSEL pin = “L” to set the slave address to “0011000” when
downloading from EEPROM by DLS bit even if the I2CSEL pin =“H” and the EXTEEP pin = “L”.
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.
Note 52. 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.
0
0
1
1
0
0
CAD R/W
When I2CSEL pin = “H” and EXTEEP pin = “L”
0
0
1
1
0
0
0
R/W
When I2CSEL pin = “H” and EXTEEP pin = “H”, or using DLS bit
Figure 66. First Byte Configuration (I²C)
1-6. The Second and Succeeding Bytes
The data format of the second and succeeding bytes of the AK7755 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) M⁽¹⁾i^マcr^イoc^コo^ンn^イtro^ンl^タle^ーr I^フn^ェte^ーrf^スac^のe^フF^ォo^ーrm^マa^ッt^ト (2) I⁽²¹C^)I2CF^のor^フm^ォa^ーt ^{マット}
A1
B2
C3
A1
B2
C3
A
A
24BIT
8BIT
8BIT
8BIT
A …Acknowledge
Figure 67. Division of Data (I²C)
Note 53. 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”.
014006643-E-00
- 81 -
2014/10