Owner's manual

Parameters and commands

Bonito Technical Manual V2.3.0

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 s

Related Parameters E, F

Example 1 K=A7 (0xA7 = 167, timer resolution of ((167 + 1) / 56 MHz) = 3 s)

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 s = 300 s

frame duration = 4,000 * 3 s = 12,000 s

Example 2 K=53 (0x53 = 83, timer resolution of ((83 + 1) / 56 MHz) = 1.5 s)

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 s = 150 s

frame duration = 4,000 * 1.5 s = 6,000 s

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)