
TMC2192
PRODUCT SPECIFICATION
24
P
Enabling the pedestal on line 25 enables it for the remainder 
of field 1, to line 262. Likewise, enabling the pedestal on line 
288 enables it for the remainder of field 2.
Pedestal Height
PEDHGT1 determines the height of the pedestal for the 
luminance channel on the composite path. The range of the 
pedestal height is from -22.1 to 21.74 IRE in .345 IRE incre-
ments. 
Sync and Blank Insertion
The composite paths blank and sync D/A codes are deter-
mined by the FORMAT control register. For NTSC and 
PAL-M formats the blank D/A code is 240 (295 mV) and the 
sync D/A code is 8 (9 mV). For all other PAL formats the 
blank D/A code is 256 (314 mV) and the sync D/A code is 
12 (14 mV).
In all cases the sync edges are sloped to insure the proper rise 
and fall times in all video standards.
Closed Caption Insertion 
Control Registers for this section
The TMC2192 includes a flexible closed-caption processor. 
It may be programmed to insert a closed caption signal on 
any line within a range of 16 lines on ODD and/or EVEN 
fields. Closed Caption insertion overrides all other configura-
tions of the encoder: if it is specified on an active video line, 
it takes precedence over the video data and removes NTSC 
setup if setup has been programmed for the active video 
lines. Closed Caption is only available when the TMC2192 
is in a 13.5 MHz pixel rate.
Closed caption is turned on by setting CCON HIGH. When-
ever the encoder begins producing a line specified by 
CCFLD and CCLINE, it will insert a closed caption line in 
its place. If CCRTS is HIGH, the data contained in CCDx 
will be sent. IF CCRTS is LOW, Null bytes (hex 00 with 
ODD parity) will be sent. 
Line Selection
The line to contain CC data is selected by a combination of 
the CCFLD bit and the CCLINE bits. CCLINE is added to 
the offset shown in Table 16 to specify the line. 
Parity Generation
Standard Closed-Caption signals employ ODD parity, which 
may be automatically generated by setting CCPAR HIGH. 
Alternatively, parity may be generated externally as part of 
the bytes to be transmitted, and, with CCPAR LOW, the 
entire 16 bits loaded into the CCDx registers will be sent 
unchanged. 
Operating Sequence
A typical operational sequence for closed-caption insertion 
on line xx is:
Read Register 1E and check that bit 7 is LOW, indicat-
ing that the CCDx registers are ready to accept data.
If ready, write two bytes of CC data into registers 1C 
and 1D. 
Write into register 1E the proper combination of 
CCFLD and CCLINE. CCPAR may be written as 
desired. Set CCRTS HIGH.
The CC data is transmitted during the specified line.
As soon as CCDx s transferred into the CC processor (and 
CCRTS goes LOW), new data may be loaded into registers 
1C and 1D. This allows the user to transmit CC data on sev-
eral consecutive lines by loading data for line n+1 while data 
is being sent on line n.
Address
0x1C
0x1D
0x1E
0x1E
0x1E
0x1E
0x1E
Bit(s)
7-6
1-0
7
6
5
4
3–0
Name
CCD1
CCD2
CCON
CCRTS
CCPAR
CCFLD
CCLINE
Table 13. Closed Caption Line Selection
Standard
525
Offset
12
274
16
328
Field
ODD
EVEN
ODD
EVEN
Lines
12-27
274-289
16-31
328-343
625