NJU26207
- 6 -
Ver.2008-12-03
I
2
C Bus
When the NJU26207 is configured for I
2
C bus communication in SEL=”Low”, the serial host interface transfers
data on the SDA pin and clocks data on the SCL pin. The SDA is an open drain pin requiring a pull-up resistance.
Pins AD1 and AD2 are used to configure the seven-bit SLAVE address of the serial host interface. (Table 6)
Table 6 I
2
C Bus Interface Slave address
* SLAVE address is 0 when AD1/2 is “Low”. SLAVE address is 1 when AD1/2 is “High”.
* SLAVE address is 0 when R/W is “W”. SLAVE address is 1 when R/W is “R”.
Note:
Both “
Standard-Mode (100kbps)” and “Fast-Mode (400kbps)” data transfer rate are supported.
4-Wire Serial Interface
The serial host interface can be configured for 4-Wire Serial bus communication by setting SEL1=”High” during the
Reset Sequence initialization. SHI bus communication is full-duplex; a write byte is shifted into the SDIN pin at the
same time that a read byte is shifted out of the SDOUT pin.
Data transfers are MSB first and are enabled by setting SSb = “Low”. Data is clocked into SDIN on rising
transitions of SCK. Data is latched at SDOUT on falling transitions of SCK except for the first byte(MSB) which is
latched on the falling transitions of SSb. SDOUT is always CMOS output. SDOUT does not require a pull-up
resistance.
Fig. 4 4-Wire Serial Interface Timing
Note :
When the data-clock is less than 8 clocks, the input data is shifted to LSB side and is sent to the DSP core at the
transition of SSb=”High”.
When the data-clock is more than 8 clocks, the last 8 bit data becomes valid.
After sending LSB data, SDOUT transmits the MSB data which is received via SDIN until SSb becomes “High”.
bit7 bit6 bit5 bit4 bit3
AD2
bit2
AD1
bit1
R/W
bit0
0 0 1 1 1 0 0
0 0 1 1 1 0 1
0 0 1 1 1 1 0
0 0 1 1 1 1 1
R/W
Start
Bit
R/W
bit
ACK
Slave Address ( 7bit )
SDIN
SDOUT
SCK
SSb
bit5
bit1
bit7
bit0
bit6
bit1
bit7
bit0
bit6 bit5
unstable
unstable
MSB LSB
