
ADV3002
Rev. B | Page 14 of 28
Source Physical Address Assignment
In HDTV applications where the CEC function is available, the
EDID contains the source physical address (SPA); a unique value
for each HDMI port. Because the memory in the
ADV3002 isvolatile, the SPA must be stored in the external EDID EEPROM.
Rather than require a larger external EEPROM to store the SPA,
because all 256 bytes of memory are needed for typical EDID
information, th
e ADV3002 takes advantage of EDID information
that is always a fixed value, such as the 24-bit IEEE registration
identifier (0x000C03). The 24 bits of the IEEE registration identifier
are replaced with the desired SPA values. When a source requests
the IEEE registration identifier, the
ADV3002 responds with the
fixed value (0x000C03). The
ADV3002 then automatically
calculates the correct checksum for each port based on the SPA
stored for that port in the vendor specific data block (VSDB).
CEC-enabled devices have a source physical address (SPA) that
allows the CEC controller to address the specific physical devices
and control switches. The SPA is comprised of four fields or
nibbles. Each field is a 4-bit number; therefore, each field can be
any one of 16 possible values (0x0 through 0xF). Each HDMI
input port is assigned a unique SPA as shown i
n Figure 28. In
any CEC-enabled device, only one of the four fields is unique
per port. In HDMI sink applications, where the sink is the root
device, only the W field is unique per port, whereas the X, Y,
and Z fields are always set to zero.
SPA = W. X. Y. Z
A typical vendor specific data block (VSDB) is shown
in Table 7.be replaced with the one shown
in Table 8, whereby the port
specific field can be assigned to any of the four fields (W, X, Y, or Z)
depending on the value set in the override select bits as shown
When calculating the checksum for Block 1 of the EDID, do not
use the custom values entered in place of the IEEE registration
identifier in the calculation; instead, use the IEEE registration
identifier values (0x000C03). Include the values in Byte 4 and
Byte 5 of the VSDB in the calculation.
HDMI
PORT A
SPA = WA. XA. YA. ZA
HDMI
PORT B
SPA = WB. XB. YB. ZB
HDMI
PORT C
SPA = WC. XC. YC. ZC
HDMI
PORT D
SPA = WD. XD. YD. ZD
ADV3002
07905-
008
Figure 28. SPA Assignments
Table 7. Typical Vendor Specific Data Block (VSDB)
Byte No.
7
6
5
4
3
2
1
0
0
Vendor specific tag
code (= 3)
Length (= N)
1
24-bit IEEE registration identifier (0x000C03)
(least significant byte first)
2
3
4
SPA Field W
SPA Field X
5
SPA Field Y
SPA Field Z
6 to N
Remainder or VSDB is stored in Byte 6 through Byte N
Table 8. Vendor Specific Data Block with ADV3002 Byte No.
7
6
5
4
3
2
1
0
0
Vendor specific
tag code (= 3)
Length (= N)
1
Port A SPA override field
Port B SPA override field
2
Port C SPA override field
Port D SPA override field
3
Not used
4
Default W field
Default X field
5
Default Y field
Default Z field
6 to N
Remainder or VSDB is stored in Byte 6 through Byte N
Table 9. Override Select Assignment
Override Select
Field Replaced by
Port-Specific SPA
Bit 3
Bit 2
Bit 1
Bit 0
1
0
W
0
1
0
X
0
1
0
Y
0
1
Z