Instruction manual

3.2.2.4. Trigger Input
There are several trigger inputs on the frame grabber - optocoupled and TTL. The optocoupled trigger
inputs have optimum noise immunity and 250 V isolation voltage. TriginOpt0+ (Trigger+ in figure below)
for instance is connected to the anode of a LED, TriginOpt0- (Trigger- in figure below) to the cathode of
the LED via an internal 220-Ohm resistor. Since the LED needs about 10..20 mA for full drive, a 5 V
voltage source or a TTL output is able to drive sufficient current through the circuit. Higher-voltage
sources may be used with additional limiting resistors. This trigger input is edge-sensitive. The use of
positive or negative edge is possible.
Caution: Do not exceed a maximum of 30 mA LED current!
Opto-coupled Trigger Input Schematic
3.2.2.5. Data Transfer of p3i_DIG
Since the p3i_DIG is a busmaster card, the video data for a single frame or a whole sequence is moved
into memory per DMA-transfer. There is no need for the CPU to support this process. The maximum
transfer rate in a system is 105 Mbytes/s typically. In a real application the transfer rate depends on the
chipset, graphic card and other active busmaster cards.
3.2.2.6. SODIMM for p3i_DIG
The SODIMM on the p3i_DIG is used as a large FIFO to buffer data especially in cases the PCI bus is
busy or data rate exceeds PCI bus bandwidth.
The SODIMM consists of SDRAM modules and is clocked with 66 MHz. "Non Mixed-Mode" module
configurations are used and each SDRAM module has 4 banks.
Chapter 3. Hardware Reference
18