AK4955 Datasheet, PDF (76/117 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK/Cap-less VIDEO-AMP/ LDO & DSP

[AK4955]
(2) DSP Access Format in I²C-bus Control Mode
1. WRITE Operation
In the AK4955, when a “Write-Slave-address assignment” is received at the first byte, the write command at the second
byte and data at the third and succeeding bytes are received. At the data block, address and write data are received in a
single-byte unit each in accordance with a command code. The number of write data bytes (*1 in Figure 68) is fixed by the
received command code.
Data writings must be executed after an Acknowledge. There are some cases that 2LRCK wait time is needed depending
on the written command. A 1byte dummy command (all “0” or “1”) must be written after inputting the data.
R/W=0
start
s
SDA
Slave
Address
Command
code
Address
Address
~~~
ACK
ACK
ACK
Address data is 2byte assignment. No address
input if there is no address.
~~~
stop
DATA
DATA
DATA
dummy
P
~~
ACK
ACK
ACK
Depending on write data length *1
ACK
Dummy 1byte
Figure 68. Write Sequence to DSP
Command Address Data Length
Content
Length
F1H~FBH 2byte
2byte Assignment ×n CRAM write preparation during RUN.
Assignment
(n=2~12)
LSB 4bits of the command code assign the number of write
operation. (F1H: 2, … FBH: 12) Write operation exceeding the
assigned number of write, abandons the data.
FCH
None
1byte Assignment External Conditional Jump Code Input
FDH
2byte
None
CRAM writing during RUN. The address is all “0” input.
Assignment
FEH
2byte
2byte Assignment ×n CRAM writing during a system reset.
Assignment
FFH
2byte
2byte Assignment ×n PRAM writing during a system reset.
Assignment
Note: Length of write data is variable with the areas to be written. When accessing RAM, it is possible to write data at
sequential address locations by writing data continuously. Writing command codes other than above are prohibited.
Table 68. List of Usable Write Command Codes in Write Sequence
MS1343-E-00
- 76 -
2011/12