ALLIED Vision Technologies Bonito CL-400 200 fps - Manual (Page 45)

Parameters and commands
Bonito Technical Manual V2.3.0
45
Timer prescaler value (K)
The prescaler value is used to divide the basic timer clock frequency of 56 MHz
by a value of (K + 1) down to a smaller clock frequency. The resulting frequency
is utilized as the time base for exposure time
E and frame duration F. This
parameter is 16 bit wide.
The implementation of this value provides flexibility between the maximum
interval length, the smallest possible resolution, and the size of the numbers
involved.
If the value K is increased while the values E and F stay the same, the real expo-
sure time and frame duration will decrease.
Range From 1 to FFFF (0xFFFF = 65535)
Default A7, leading to 3 μs
Related Parameters E, F
Example 1 K=A7 (0xA7 = 167, timer resolution of ((167 + 1) / 56 MHz) = 3 μs)
E=64 (0x64 = 100, sets exposure time to 100 prescaler ticks)
F=FA0 (0xFA0 = 4,000, set frame duration to 4,000 prescaler ticks)
Result:
exposure time: 100 * 3 μs = 300 μs
frame duration = 4,000 * 3 μs = 12,000 μs
Example 2 K=53 (0x53 = 83, timer resolution of ((83 + 1) / 56 MHz) = 1.5 μs)
E=64 (0x64 = 100, sets exposure time to 100 prescaler ticks)
F=FA0 (0xFA0 = 4,000, set frame duration to 4,000 prescaler ticks)
Result:
exposure time: 100 * 1.5 μs = 150 μs
frame duration = 4,000 * 1.5 μs = 6,000 μs
Exposure control mode (M)
Use parameter M to setup the exposure control mode. The exposure control
depends on a number of general timing parameters that are specified in the
table below.
Note

Use exact multiples of the current line duration to minimize
exposure and frame-to-frame jitter. (
K=A7 for 3 μs, K=53 for
1.5 μs)