BU94601KV_12 Datasheet, PDF (18/70 Pages) Rohm – AAC/WMA/MP3 +SD Memory Card + iPod

BU94601KV BU94603KV BU94604BKV
Datasheet
11.2 Slave address
An I²C bus slave address corresponds to the 7-bit addressing mode. As shown in Table 3., you can select the
slave address using input of A0 terminal and A1 terminal. Figure 11 shows the slave address transfer format.
S
A6
A5
A4
A3
A2
A1
A0 R/W ACK
Start
condition
Slave Address
R / W = Read / Write Pulse
ACK = Acknowledge
sent by
slave
Figure 11 Slave Address Transfer Format
Table 3. Settable Slave Addresses
MSB
A6
A5
A4
A3
A2
A1
terminal
LSB
A0
terminal
10000
0
0
10000
0
1
10000
1
0
10000
1
1
11.3 Write protocol from master
To send a master command using an I²C bus, follow the transfer protocol shown in Figure 12. For details on
each command, see Chapter of “Command operation”.
S Slave Address R/W A Data(8bit) A Data(8bit) A
Data(8bit)
"0"(write)
From Master to Slave
From Slave to Master
A = Acknowledge(SDA low)
A = No Acknowledge(SDA high)
S = Start Condition
P = Stop condition
Figure 12 Command send protocol
A/A P
11.4 Read protocol to master
To send reception data using an I²C bus from the slave to the master, follow the transfer protocol shown in
Figure 13. First, transfer the status read command (step1). Then, input SCL clock of required bytes in step 2 to
read the status.
When the device is BUSY at reception of device status or memory data, the I²C bus may possibly be occupied
by the device during BUSY. This LSI transfers the bus to the master so as not to generate such bus
occupation. However, as a BUSY state still exists inside of the system, appropriate data may not be
transferred during BUSY. Therefore, the first byte of transfer data (Step2) is used to judge the transfer data is
enabled/disabled. When specifying addresses from the master to the slave and the first byte of the transfer
data immediately after data transfer is required is 0x00, transfer data from the slave is enabled. If the first byte
is 0xFF, it shows the BUSY state. Therefore, the transfer data should be disabled. If this happens, retry
command transfer at Step 1 to read out the status.
Figure 14 shows the relationship between the transfer data and BUSY.
* For further information on BUSY, see Chapter 17.
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