Basler Vision Technologies Sprint Series, User Manual

Page: 99 / 236

Video Data Output Modes
Basler sprint Mono Cameras 89
2 Tap - 8 Bit Output Mode
Operation in 2 tap 8 bit mode is similar to 2 tap 12 bit mode. In 8 bit mode, however, the four least
significant bits output from the camera’s ADCs are dropped and only the 8 most significant bits of
data per pixel are transmitted.
5.2.1.1 Video Data Sequence for 2 Tap Output Modes
When the camera is not transmitting valid data, the line valid and data valid bits sent on each cycle
of the pixel clock will be low.
Once the camera has completed an exposure, there will be a delay while data is read out of the
sensor. When readout is complete, the camera will begin to transmit pixel data:
„
On the clock cycle where valid pixel data transmission begins, the line valid and data valid bits
both become high. Two data streams, D0 and D1 are transmitted in parallel during this clock
cycle. On this clock cycle, data stream D0 will transmit data for pixel 1 in the line. Data stream
D1 will transmit data for pixel 2. Depending on the video data output mode selected, the pixel
data will be at 12 bit, 10 bit, or 8 bit depth.
„
On the next cycle of the pixel clock, the line valid and data valid bits will both be high. On this
clock cycle, data stream D0 will transmit data for pixel 3 in the line. Data stream D1 will
transmit data for pixel 4.
„
On the next cycle of the pixel clock, the line valid and data valid bits will be high. On this clock
cycle, data stream D0 will transmit data for pixel 5 in the line. Data stream D1 will transmit data
for pixel 6.
„
This pattern will continue until all of the pixel data for the line has been transmitted.
„
After all of the pixel data for the line has been transmitted, the line valid and data valid bits both
become low indicating that valid pixel data is no longer being transmitted.
Figure 35 on page 91 shows the data sequence when the camera is operating in edge-controlled
or level-controlled exposure mode. Figure 36 on page 92 shows the data sequence when the
camera is operating in programmable exposure mode.
Note
The video data output mode that you select may affect the camera’s maximum
allowed line rate. See Section 4.3 on
page 74 .
The data sequence outlined below, along with Figure 35 on page 91 and
Figure 36 on page 92 , describes what is happening at the inputs to the
Camera Link transmitters in the camera.