Frame Pointers Gray Code Outputs - 6.3 English

AXI Video Direct Memory Access v6.3 Product Guide (PG020)

Document ID
PG020
Release Date
2022-06-08
Version
6.3 English

Table: Genlock Gray Code, Table: Gen-Lock Gray Codes (Frame Store 17 to 32) , and Table: Gen-Lock Gray Codes (Frame Store 17 to 32)  list the Gray Codes that are used for each of the 32 possible Frame Store sizes. The Gray Code cycles through all of the codes on the first line first and then cycles through all of the codes on the second line before repeating the first line. Number of Gray codes is double the number of frame buffers to allow for non-power-of-two frame buffer values to be cycled through and still maintain Gray code coherency with minimal FPGA resources required.

 

IMPORTANT:   AXI VDMA does not support intra-frame mode. Genlock synchronization cannot be provided for writing and reading the same frame with a predetermined delay between write and read operations.

Table C-1:      Genlock Gray Code

 

 

 

 

FRMSTORE

Gray Code

Frame Number

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1

0

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

0

3

1

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

1

6

3

7

2

5

 

 

 

 

 

 

 

 

 

 

 

 

 

4

0

6

1

7

3

5

2

4

 

 

 

 

 

 

 

 

 

 

 

 

5

2

12

6

13

7

15

5

14

4

10

 

 

 

 

 

 

 

 

 

 

 

6

3

12

2

13

6

15

7

14

5

10

4

11

 

 

 

 

 

 

 

 

 

 

7

1

12

3

13

2

15

6

14

7

10

5

11

4

9

 

 

 

 

 

 

 

 

 

8

0

12

1

13

3

15

2

14

6

10

7

11

5

9

4

8

 

 

 

 

 

 

 

 

9

4

24

12

25

13

27

15

26

14

30

10

31

11

29

9

28

8

20

 

 

 

 

 

 

 

10

5

24

4

25

12

27

13

26

15

30

14

31

10

29

11

28

9

20

8

21

 

 

 

 

 

 

11

7

24

5

25

4

27

12

26

13

30

15

31

14

29

10

28

11

20

9

21

8

23

 

 

 

 

 

12

6

24

7

25

5

27

4

26

12

30

13

31

15

29

14

28

10

20

11

21

9

23

8

22

 

 

 

 

13

2

24

6

25

7

27

5

26

4

30

12

31

13

29

15

28

14

20

10

21

11

23

9

22

8

18

 

 

 

14

3

24

2

25

6

27

7

26

5

30

4

31

12

29

13

28

15

20

14

21

10

23

11

22

9

18

8

19

 

 

15

1

24

3

25

2

27

6

26

7

30

5

31

4

29

12

28

13

20

15

21

14

23

10

22

11

18

9

19

8

17

 

16

0

24

1

25

3

27

2

26

6

30

7

31

5

29

4

28

12

20

13

21

15

23

14

22

10

18

11

19

9

17

8

16

Table C-2:      Gen-Lock Gray Codes (Frame Store 17 to 32) 

 

 

 

 

FRMSTORE

Gray Code

Frame Number

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

17

8

48

24

49

25

51

27

50

26

54

30

55

31

53

29

52

28

60

20

61

21

63

23

62

22

58

18

59

19

57

17

56

18

9

48

8

49

24

51

25

50

27

54

26

55

30

53

31

52

29

60

28

61

20

63

21

62

23

58

22

59

18

57

19

56

19

11

48

9

49

8

51

24

50

25

54

27

55

26

53

30

52

31

60

29

61

28

63

20

62

21

58

23

59

22

57

18

56

20

10

48

11

49

9

51

8

50

24

54

25

55

27

53

26

52

30

60

31

61

29

63

28

62

20

58

21

59

23

57

22

56

21

14

48

10

49

11

51

9

50

8

54

24

55

25

53

27

52

26

60

30

61

31

63

29

62

28

58

20

59

21

57

23

56

22

15

48

14

49

10

51

11

50

9

54

8

55

24

53

25

52

27

60

26

61

30

63

31

62

29

58

28

59

20

57

21

56

23

13

48

15

49

14

51

10

50

11

54

9

55

8

53

24

52

25

60

27

61

26

63

30

62

31

58

29

59

28

57

20

56

24

12

48

13

49

15

51

14

50

10

54

11

55

9

53

8

52

24

60

25

61

27

63

26

62

30

58

31

59

29

57

28

56

25

4

48

12

49

13

51

15

50

14

54

10

55

11

53

9

52

8

60

24

61

25

63

27

62

26

58

30

59

31

57

29

56

26

5

48

4

49

12

51

13

50

15

54

14

55

10

53

11

52

9

60

8

61

24

63

25

62

27

58

26

59

30

57

31

56

27

7

48

5

49

4

51

12

50

13

54

15

55

14

53

10

52

11

60

9

61

8

63

24

62

25

58

27

59

26

57

30

56

28

6

48

7

49

5

51

4

50

12

54

13

55

15

53

14

52

10

60

11

61

9

63

8

62

24

58

25

59

27

57

26

56

29

2

48

6

49

7

51

5

50

4

54

12

55

13

53

15

52

14

60

10

61

11

63

9

62

8

58

24

59

25

57

27

56

30

3

48

2

49

6

51

7

50

5

54

4

55

12

53

13

52

15

60

14

61

10

63

11

62

9

58

8

59

24

57

25

56

31

1

48

3

49

2

51

6

50

7

54

5

55

4

53

12

52

13

60

15

61

14

63

10

62

11

58

9

59

8

57

24

56

32

0

48

1

49

3

51

2

50

6

54

7

55

5

53

4

52

12

60

13

61

15

63

14

62

10

58

11

59

9

57

8

56

Table C-3:      Gen-Lock Gray Codes (Frame Store 17 to 32) 

 

 

 

 

FRMSTORE

Gray Code

Frame Number

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

17

16

40

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18

17

40

16

41

 

 

 

 

 

 

 

 

 

 

 

 

 

 

19

19

40

17

41

16

43

 

 

 

 

 

 

 

 

 

 

 

 

 

20

18

40

19

41

17

43

16

42

 

 

 

 

 

 

 

 

 

 

 

 

21

22

40

18

41

19

43

17

42

16

46

 

 

 

 

 

 

 

 

 

 

 

22

23

40

22

41

18

43

19

42

17

46

16

47

 

 

 

 

 

 

 

 

 

 

23

21

40

23

41

22

43

18

42

19

46

17

47

16

45

 

 

 

 

 

 

 

 

 

24

20

40

21

41

23

43

22

42

18

46

19

47

17

45

16

44

 

 

 

 

 

 

 

 

25

28

40

20

41

21

43

23

42

22

46

18

47

19

45

17

44

16

36

 

 

 

 

 

 

 

26

29

40

28

41

20

43

21

42

23

46

22

47

18

45

19

44

17

36

16

37

 

 

 

 

 

 

27

31

40

29

41

28

43

20

42

21

46

23

47

22

45

18

44

19

36

17

37

16

39

 

 

 

 

 

28

30

40

31

41

29

43

28

42

20

46

21

47

23

45

22

44

18

36

19

37

17

39

16

38

 

 

 

 

29

26

40

30

41

31

43

29

42

28

46

20

47

21

45

23

44

22

36

18

37

19

39

17

38

16

34

 

 

 

30

27

40

26

41

30

43

31

42

29

46

28

47

20

45

21

44

23

36

22

37

18

39

19

39

17

34

16

35

 

 

31

25

40

27

41

26

43

30

42

31

46

29

47

28

45

20

44

21

36

23

37

22

39

18

36

19

34

17

35

16

33

 

32

24

40

25

41

27

43

26

42

30

46

31

47

29

45

28

44

20

36

21

37

23

39

22

38

18

34

19

35

17

33

16

32

The Gray codes received by the Genlock slave are then converted to a frame reference to tell the Genlock slave which frame to work on. The slave modifies the Genlock frame reference received by the frame delay such that the Genlock slaves remain a Frame Delay behind the Genlock Master. Table: Example Gray Code Conversion for Frame Buffers= 5  illustrates an example conversion from Genlock Gray Code to Frame Reference used by the Genlock Slave.

Table C-4:      Example Gray Code Conversion for Frame Buffers= 5

Gray To Frame Conversion

Gray Code Progressions for Frame Buffers = 5

Gray Code

2

6

7

5

4

12

13

15

14

10

Decoded Frame Reference

0

1

2

3

4

0

1

2

3

4

 

Note:   In some situations (like when the channel is halted or the input frame pointer reference reaches a terminal point in the row), the frame pointer out from MM2S/S2MM channel toggles in the column between two values for the same frame number.