11
B. Digital Control Inputs
Four clock inputs (Tap
n
_PIXCK) come in through the input connector J1A/J1B. These inputs
are received by high-speed differential receivers. The outputs of these receivers go to
dedicated global clock inputs. PIX_CLK1 should be used for multi-tap cameras.
Programmable clock polarity and input delay allow compensation for clock to data skew.
Eight additional control inputs (Tap
n
_LVAL and Tap
n
_FVAL) come in through the Digital input
connector J1A/J1B. These inputs are received by high-speed differential receivers. The
outputs of these receivers (LVAL
n
, FVAL
n
) go to the FPGAs. These lines may be used for
frame valid and line valid signals when attaching multiple cameras.
Four general purpose static inputs (GPIN
n
) are provided. These inputs are received by
differential receivers. The outputs of these receivers can be read by the primary TriMedia via
the I
2
C bus.
C. Digital Control Outputs
Two outputs are provided for line or frame start. The two frame start signals are generated in
the CPLD in response to external trigger inputs (after a programmed delay) or on command of
the primary TM1300. These differential outputs are intended for use with line scan or area
scan cameras which require a scan start pulse.
Two outputs are provided for exposure control. These differential outputs are intended for
use with line scan or area scan cameras which require a scan start pulse. They are
generated in the CPLD in response to external trigger inputs (without a delay) or on command
of the primary TM1300. Camera exposure time is controlled by the delay between these
signals and the line / frame start signals.
Two master clock outputs are provided to generate a time base for cameras. These RS422
differential outputs are intended for use with line scan or area scan cameras which require an
external time base.
Four general purpose static outputs are provided. These RS422 differential outputs can be
written directly by the primary TM1300 via the I
2
C bus.
1.
Frame/Line Start and Exposure
Four strobe lines, STROBE1-STROBE4, are output to connector J1A/J1B. These RS422
differential outputs are for line scan or area scan cameras which require a scan start
pulse, readout, or exposure control signals (e.g., EXSYNC and PRIN to Dalsa cameras).
The CPLD has two counters for generating line/frame start and exposure timing signals.
STROBE1 outputs Counter1 start, STROBE2 outputs Counter1 exposure. STROBE3
outputs Counter2 start, and STROBE4 outputs Counter2 exposure.
The camera control signals provide a flexible control interface. In a typical application, a
Cmp1 signal could be used to start camera exposure. The corresponding Cmp2 signal
could initiate transmission of the camera data to the FastImage.
2.
Master Clocks
Four master clock outputs (MASTER_CK
n
) to connector J1A/J1B are provided to
generate a time base for cameras. These RS422 differential outputs are intended for use
with line scan or area scan cameras which require an external time base. Master clock
outputs are generated by the primary and secondary TriMedia’s using the AI_OSCLK
outputs. Only one clock source is available on the single processor model. These pins
can generate any frequency from 1 Hz to 40 MHz in .07 Hz steps using the direct digital
synthesizer of the TriMedia. Nominal jitter on these outputs due to digital synthesis is 3.3
