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AR# 47425

Virtex-7 FPGA GTH Transceiver - Eye Scan Use Mode Change

Description

For proper Eye Scan operation in the 16 and 32-bit data widths in Virtex-7 GTH Transceivers Initial ES Silicon, changes need to be made in the implementation of the Eye Scan offset settings.

Solution

For eye scan, a horizontal offset count would normally be loaded into the lower 11 bits of the horizontal offset ES_HORZ_OFFSET as described in the User Guide.Instead, load the default value for the given application into ES_HORZ_OFFSET.For the default values, see the User Guide. The lower 7 bits of the intended horizontal offset need to be loaded into RXCDR_CFG[82:76] in a gray code format.See the table below for the decimal/gray code conversion. This 7 bit value should only be changed in 1 step increments. For example, if you want to change the offset from 8 to 12, you would step through 9, 10, and 11 before getting to 12.Bit 11 (called "phase unification" in the User Guide) still needs to be written to the ES_HORZ_OFFSET[11] without changing the default value in ES_HORZ_OFFSET[10:0] that was set earlier. Note that by changing only bit 11 and the lower 7 bits, you can reach all of the offsets shown in the User Guide for the supported widths.

Decimal Binary
Unencoded
Decimal
Gray Code
Binary
Gray Code
64 1000000 96 1100000
65 1000001 97 1100001
66 1000010 99 1100011
67 1000011 98 1100010
68 1000100 102 1100110
69 1000101 103 1100111
70 1000110 101 1100101
71 1000111 100 1100100
72 1001000 108 1101100
73 1001001 109 1101101
74 1001010 111 1101111
75 1001011 110 1101110
76 1001100 106 1101010
77 1001101 107 1101011
78 1001110 105 1101001
79 1001111 104 1101000
80 1010000 120 1111000
81 1010001 121 1111001
82 1010010 123 1111011
83 1010011 122 1111010
84 1010100 126 1111110
85 1010101 127 1111111
86 1010110 125 1111101
87 1010111 124 1111100
88 1011000 116 1110100
89 1011001 117 1110101
90 1011010 119 1110111
91 1011011 118 1110110
92 1011100 114 1110010
93 1011101 115 1110011
94 1011110 113 1110001
95 1011111 112 1110000
96 1100000 80 1010000
97 1100001 81 1010001
98 1100010 83 1010011
99 1100011 82 1010010
100 1100100 86 1010110
101 1100101 87 1010111
102 1100110 85 1010101
103 1100111 84 1010100
104 1101000 92 1011100
105 1101001 93 1011101
106 1101010 95 1011111
107 1101011 94 1011110
108 1101100 90 1011010
109 1101101 91 1011011
110 1101110 89 1011001
111 1101111 88 1011000
112 1110000 72 1001000
113 1110001 73 1001001
114 1110010 75 1001011
115 1110011 74 1001010
116 1110100 78 1001110
117 1110101 79 1001111
118 1110110 77 1001101
119 1110111 76 1001100
120 1111000 68 1000100
121 1111001 69 1000101
122 1111010 71 1000111
123 1111011 70 1000110
124 1111100 66 1000010
125 1111101 67 1000011
126 1111110 65 1000001
127 1111111 64 1000000
0 0000000 0 0000000
1 0000001 1 0000001
2 0000010 3 0000011
3 0000011 2 0000010
4 0000100 6 0000110
5 0000101 7 0000111
6 0000110 5 0000101
7 0000111 4 0000100
8 0001000 12 0001100
9 0001001 13 0001101
10 0001010 15 0001111
11 0001011 14 0001110
12 0001100 10 0001010
13 0001101 11 0001011
14 0001110 9 0001001
15 0001111 8 0001000
16 0010000 24 0011000
17 0010001 25 0011001
18 0010010 27 0011011
19 0010011 26 0011010
20 0010100 30 0011110
21 0010101 31 0011111
22 0010110 29 0011101
23 0010111 28 0011100
24 0011000 20 0010100
25 0011001 21 0010101
26 0011010 23 0010111
27 0011011 22 0010110
28 0011100 18 0010010
29 0011101 19 0010011
30 0011110 17 0010001
31 0011111 16 0010000
32 0100000 48 0110000
33 0100001 49 0110001
34 0100010 51 0110011
35 0100011 50 0110010
36 0100100 54 0110110
37 0100101 55 0110111
38 0100110 53 0110101
39 0100111 52 0110100
40 0101000 60 0111100
41 0101001 61 0111101
42 0101010 63 0111111
43 0101011 62 0111110
44 0101100 58 0111010
45 0101101 59 0111011
46 0101110 57 0111001
47 0101111 56 0111000
48 0110000 40 0101000
49 0110001 41 0101001
50 0110010 43 0101011
51 0110011 42 0101010
52 0110100 46 0101110
53 0110101 47 0101111
54 0110110 45 0101101
55 0110111 44 0101100
56 0111000 36 0100100
57 0111001 37 0100101
58 0111010 39 0100111
59 0111011 38 0100110
60 0111100 34 0100010
61 0111101 35 0100011
62 0111110 33 0100001
63 0111111 32 0100000
AR# 47425
Date Created 05/02/2012
Last Updated 12/15/2012
Status Active
Type General Article
Devices
  • Virtex-7
  • Virtex-7 HT