
ADV7170/ADV7171
–29–
REV. 0
TC01
TC00
TC07
TC02
TC04
TC03
TC05
TC06
TTXREQ RISING EDGE CONTROL
TC07 TC06
TC05 TC04
0
0
"
1
1
0
0
"
1
1
0
0
"
1
1
0
1
"
0
1
0 PCLK
1 PCLK
" PCLK
14 PCLK
15 PCLK
TTXREQ FALLING EDGE CONTROL
TC03 TC02
TC01 TC00
0
0
"
1
1
0
0
"
1
1
0
0
"
1
1
0
1
"
0
1
0 PCLK
1 PCLK
" PCLK
14 PCLK
15 PCLK
Figure 50. Teletext Control Register
CGMS CRC CHECK
CONTROL
C/W04
0
1
DISABLE
ENABLE
WIDE SCREEN SIGNAL
CONTROL
C/W07
0
1
DISABLE
ENABLE
C/W07
C/W06
C/W05
C/W04
C/W03
C/W02
C/W01
C/W00
CGMS ODD FIELD
CONTROL
C/W05
0
1
DISABLE
ENABLE
C/W03–C/W00
CGMS DATA BITS
CGMS EVEN FIELD
CONTROL
C/W06
0
1
DISABLE
ENABLE
Figure 51. CGMS_WSS Register 0
C/W0 BIT DESCRIPTION
CGMS Data Bits (C/W03–C/W00)
These four data bits are the final four bits of CGMS data output
stream. Note it is CGMS data ONLY in these bit positions, i.e.,
WSS data does not share this location.
CGMS CRC Check Control (C/W04)
When this bit is enabled (“1”), the last six bits of the CGMS
data, i.e., the CRC check sequence, is calculated internally by
the ADV7170/ADV7171. If this bit is disabled (“0”) the CRC
values in the register are output to the CGMS data stream.
CGMS Odd Field Control (C/W05)
When this bit is set (“1”), CGMS is enabled for odd fields.
Note this is only valid in NTSC mode.
CGMS Even Field Control (C/W06)
When this bit is set (“1”), CGMS is enabled for even fields.
Note this is only valid in NTSC mode.
WSS Control (C/W07)
When this bit is set (“1”), wide screen signaling is enabled. Note
this is only valid in PAL mode.
CGMS_WSS REGISTER 1 C/W1 (C/W17–C/W10)
(Address [SR4–SR0] = 17H)
CGMS_WSS register 1 is an 8-bit-wide register. Figure 52
shows the operations under the control of this register.
C/W1 BIT DESCRIPTION
CGMS/WSS Data Bits (C/W15–C/W10)
These bit locations are shared by CGMS data and WSS data. In
NTSC mode these bits are CGMS data. In PAL mode these
bits are WSS data.
CGMS Data Bits (C/W17–C/W16)
These bits are CGMS data bits only.
CGMS_WSS REGISTER 2 C/W1 (C/W27–C/W20)
(Address [SR4–SR0] = 18H)
CGMS_WSS register 2 is an 8-bit-wide register. Figure 53
shows the operations under the control of this register.
C/W2 BIT DESCRIPTION
CGMS/WSS Data Bits (C/W27–C/W20)
These bit locations are shared by CGMS data and WSS data. In
NTSC mode these bits are CGMS data. In PAL mode these
bits are WSS data.
C/W17
C/W16
C/W15
C/W14
C/W13
C/W12
C/W11
C/W10
C/W15–C/W10
CGMS/WSS DATA
C/W17 C/W16
CGMS DATA ONLY
Figure 52. CGMS_WSS Register 1
C/W27
C/W26
C/W25
C/W24
C/W23
C/W22
C/W21
C/W20
C/W27–C/W20
CGMS/WSS DATA
Figure 53. CGMS_WSS Register 2