VG6640 datasheet(76/126 Pages) STMICROELECTRONICS

76 / 126 page

Video timing

VG6640, VD6640

76/126

DocID023597 Rev 11

6.4

Variable line length and frame length

The frame rate of the array readout and therefore the output is governed by the line length,

the frame length and the video timing pixel clock frequency.

The frame rate in frames per second (fps) may be calculated as:

where:

•

line_length_pck is the line length, register Line_Length_PCK (0x0342)

•

frame_length_lines is the frame length, register FrameLengthLines(0x212d)

The output frame rate of image sensor may be reduced by extending either the line length or

the frame length. The extension is achieved by adding extra blank pixels at the end of a line

or blank lines to act as timing padding.

Reducing the frame rate by extending the frame length (and not the line length) has the

advantage that it does not reduce the pixel readout rate or the active frame time. Therefore

it minimises potential unwanted motion artefacts in the image.

Frame timing examples are shown in Table 34.

Framerate

VT_PixelClock_MHz

line_length_pck

frame_length_lines

---------------------------------------------------------------------------------------------------

Table 34. External clock frequency examples, full FOV, 45 fps

Ext Clk

Freq

Pre-PLL

Clk Div

PLL

multiplier

VT Sys

Clk Div

VT pixel

Clk Div

VT pixel

clock

OP Sys

Clk Div

OPpixel

Clk Div

OP pixel

clock

Line

length

Frame

length

MHz

Integer

(Dec)

Integer

MHz

Integer

MHz

Pixel

Clks

Lines

(Dec)

132

49.50

1438

1023

132

49.50

1438

1023

117

65.81

49.36

1438

1023

65.63

49.22

1438

1023

126

65.63

49.22

1438

1023

VG6640 Datasheet(PDF) 76 Page - STMicroelectronics

VG6640 Datasheet(HTML) 76 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL