Instruction manual

Guppy PRO Technical ManualV4.1.0
75
Camera interfaces
PWM: Examples in practice
In this chapter we give you two examples, how to write values in the PWM regis-
ters. All values have to be written in microseconds (μs) in the PWM registers;
therefore, remember always the factor 10
-6
s.
Example 1:
Set PWM with 1kHz at 30% pulse width.
Example 2:
Set PWM with 250 Hz at 12% pulse width.
Pixel data
Pixel data are transmitted as isochronous data packets in accordance with the
1394 interface described in IIDC V1.31. The first packet of a frame is identified
by the 1 in the sync bit (sy) of the packet header.
Formula 2: PWM example 1
Formula 3: PWM example 2
RegPeriod
1
frequency
6–
10 s
------------------------------------------
1
1kHz
6–
10 s
------------------------------
1000===
RegPulseWidth RegPeriod 30% 1000 30% 300===
RegPeriod
1
frequency
6–
10 s
------------------------------------------
1
250Hz
6–
10 s
----------------------------------
4000===
RegPulseWidth RegPeriod 12% 4000 12% 480===
0-7 8-15 16-23 24-31
data_length tg channel tCode sy
header_CRC
Video data payload
data_CRC
Table 33: Isochronous data block packet format. Source: IIDC V1.31
sync bit