I am attempting to use a TVP5160 to decode CGMS-A Type A packets on line 41 of a 480p video signal.
The TVP5160 is running on a TVP5160EVM evaluation board and controlled using TI WinVCC4 v4.56 software.
After initializing the decoder for 480p input video, and verifying that the TVP5160 is locked to the incoming video (Status Register 1 = 06), I have configured the the following registers to capture line 41 data:
VDP Line Stop register (D7h) = 2Ah (42) - extend the VDP range to include line 41
VDP Line Address register (80 0600h) = 29h (41) - set the capture line
VDP Line Mode register (80 0601h) = 02h - line mode: WSS/CGMS, Field 1, disable error detection
Results:
Test 1 CGMS 1,0 APS 0,0
Line 41 video data as observed on an oscilloscope:
Byte 1 - 00h
Byte 2 - 01h
Line 41 video data as captured by TVP5160 decoder (80 0520h & 80 0521h):
Byte 1 - 20h
Byte 2 - 00h
Test 2 CGMS 1,1 APS 0,1
Line 41 video data as observed on an oscilloscope:
Byte 1 - 00h
Byte 2 - 0Bh
Line 41 video data as captured by TVP5160 decoder (80 0520h & 80 0521h):
Byte 1 - 20h
Byte 2 - 45h
Test 3 CGMS 1,1 APS 1,0
Line 41 video data as observed on an oscilloscope:
Byte 1 - 00h
Byte 2 - 07h
Line 41 video data as captured by TVP5160 decoder (80 0520h & 80 0521h):
Byte 1 - 20h
Byte 2 - 41h
Test 4 CGMS 1,1 APS 1,1
Line 41 video data as observed on an oscilloscope:
Byte 1 - 00h
Byte 2 - 0Fh
Line 41 video data as captured by TVP5160 decoder (80 0520h & 80 0521h):
Byte 1 - 20h
Byte 2 - 03h
The TVP5160 seems to be capturing some of the line 41 data with that data shifted one position toward the LSB. In Test 4 there are fewer 1's in the TVP data than in the video data.
Am I missing some configuration steps that are necessary to properly capture this data?
Any help would be appreciated.
Thanks,
Rich
