PanelBus
SLDS149 − AUGUST 2004
19
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
I
2
C register map (continued)
VEN_ID
Subaddress = C0
Read Only
Default = 4C
7
6
5
4
3
2
1
0
VEN_ID[7:0]
Subaddress = C1
Read Only
Default = 01
7
6
5
4
3
2
1
0
VEN_ID[15:8]
This read-only register contains the 16-bit Texas Instruments vendor ID for the TFP503. VEN_ID[15:0] is
hardwired to 0x014C.
DEV_ID
Subaddress = C2
Read Only
Default = 01
7
6
5
4
3
2
1
0
DEV_ID[7:0]
Subaddress = C3
Read Only
Default = 05
7
6
5
4
3
2
1
0
DEV_ID[15:8]
This read-only register contains the 16-bit device ID for the TFP503. DEV_ID[15:0] is hardwired to 0x0501.
REV_ID
Subaddress = C4
Read Only
Default = 01
7
6
5
4
3
2
1
0
REV_ID[7:0]
This read-only register contains the 8-bit revision ID for the TFP503. REV_ID[7:0] is hardwired to 0x01.
I
2
C interface
The I
2
C interface accesses the internal TFP503 registers. This two-terminal interface consists of one clock line,
DDC_SCL, and one serial data line, DDC_SDA. The basic I
2
C access cycles are shown in Figures 16 and 17.
DDC_SDA
Start Condition (S)
Stop Condition (P)
DDC_SCL
Figure 16. I
2
C Start and Stop Conditions
The basic access cycle consists of the following:
D
A start condition
D
A slave address cycle
D
A subaddress cycle
D
Any number of data cycles
D
A stop condition
