Datasheet
Functional Description
24
SLES099C—March 2007TVP5147PFP
Because SDA and SCL are kept open-drain at a logic-high output level or when the bus is not driven, the user
must connect SDA and SCL to a positive supply voltage via a pullup resistor on the board. The slave addresses
select signal, terminal 37 (I2CA), enables the use of two TVP5147 devices tied to the same I
2
C bus, because
it controls the least significant bit of the I
2
C device address.
Table 2−4. I
2
C Host Interface Terminal Description
SIGNAL TYPE DESCRIPTION
I2CA I Slave address selection
SCL I Input clock line
SDA I/O Input/output data line
2.6.1 Reset and I
2
C Bus Address Selection
The TVP5147 decoder can respond to two possible chip addresses. The address selection is made at reset
by an externally supplied level on the I2CA terminal. The TVP5147 decoder samples the level of terminal 37
at power up or at the trailing edge of RESETB and configures the I
2
C bus address bit A0. The I2CA terminal
has an internal pulldown resistor to pull the terminal low to set a zero.
Table 2−5. I
2
C Address Selection
A6 A5 A4 A3 A2 A1 A0 (I2CA) R/W HEX
1 0 1 1 1 0 0 (default) 1/0 B9/B8
1 0 1 1 1 0 1
†
1/0 BB/BA
†
If terminal 37 is strapped to DVDD via a 2.2-kΩ resistor, I
2
C device address A0 is set to 1.
2.6.2 I
2
C Operation
Data transfers occur using the following illustrated formats.
S 10111000 ACK Subaddress ACK Send data ACK P
Read from I
2
C control registers
S 10111000 ACK Subaddress ACK S 10111001 ACK Receive data NAK P
S = I
2
C bus start condition
P = I
2
C bus stop condition
ACK = Acknowledge generated by the slave
NAK = Acknowledge generated by the master, for multiple-byte read master with ACK each byte except
last byte
Subaddress = Subaddress byte
Data = Data byte. If more than one byte of data is transmitted (read and write), the subaddress pointer is
automatically incremented.
I
2
C bus address = Example shown that I
2
CA is in default mode. Write (B8h), read (B9h)
2.6.3 VBUS Access
The TVP5147 decoder has additional internal registers accessible through an indirect access to an internal
24-bit address wide VBUS. Figure 2−23 shows the VBUS register access.