MULTICHANNEL SYSTEMS USB-ME128-System, System Manual

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Troubleshooting
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5.3.5 Rear Panel
5.3.6 Digital In / Out
A Digital IN / OUT for 16 digital in- and output bits is available (68-pin MCS standard connector). The Digital
IN / OUT connection accepts or generates standard TTL signals. TTL stands for Transistor-Transistor Logic.
A TTL pulse is defined as a digital signal for communication between two devices. A voltage between 0 V
and 0.8 V is considered as a logical state of 0 (LOW), and a voltage between 2 V and 5 V means 1 (HIGH).
The Digital OUT allows generating a digital signal with up to 16 bits and read it out, for example, by using
a Signal Divider SD16 from MCS. You can utilize this digital signal to control and synchronize other devices
with the
USB-ME256
. Bit 0 of the Digital OUT is separated and available as Lemo connector DIG OUT D0.
So if you need only one bit of the digital signal, you don’t need the additional signal divider SD16. Please
read chapter "Pin Layout" (Digital IN / OUT Connector) in the Appendix for more information.
The Digital IN can be used to record additional information from external devices as a 16-bit encoded
number. The Digital IN is most often used to trigger recordings with a TTL signal from a stimulator.
Therefore, the bits 0, 1, 2 and 3 of the Digital IN are accessible as the Lemo connectors on the front panel
as Digital Trigger Inputs 0 to 3.
The 16 digital input channels are represented as the Digital Data stream, that is, a stream of 16-bit values,
each bit (0 to15) representing one digital input. Standard TTL signals are accepted as input signals on the
digital inputs. Unused input bits, which have an undefined state, should be masked in the Trigger Detector
of MC_Rack.
Warning: A voltage that is higher than +5 Volts or lower than 0 Volts, that is, a negative voltage,
applied to the digital input would destroy the electronics. Make sure that you apply only TTL pulses
(0 to 5 V) to the digital inputs.