TDT RZ2 Manual page 150

3-18
Analog Input/Output
The RX6 has two channels of 24-bit, sigma-delta D/A and two channels of 24-bit,
sigma-delta A/D, each accessible through BNC connectors. Sigma-delta converters
provide superior conversion quality and extended useful bandwidths, at the cost of an
inherent fixed group delay. The RX6 DAC Delay is 43 samples and the RX6 A
Delay is 70 samples.
This device can sample at rates up to ~260 kHz for a realizable bandwidth of ~109
kHz. For specific information on the actual sampling rates see "Realizable Sampling
Rates for the RX6" on page 3-20.
Important! Because some RX6 models can acquire analog signals using a Medusa preamplifier
via an optional fiber optic port, the sigma-delta A/D inputs on all RX6 models are
offset and accessed as A channels 128 and 129.
Digital I/O
The RX6 processor includes 24 bits of programmable I/O in two eight bit word-
addressable bytes and eight bits of bit-addressable I/O. Digital I/O lines are
accessed via the 25-pin connector on the front panel and can be configured as
inputs or outputs.
See the "Digital I/O Circuit Design" section of the
information on programming the digital I/O.
The first four bits of digital I/O (bits 0-3) can also be used for submicrosecond
event timing. See the "TimeStamp" component in the
information.
CAUTION!: The first eight bits of bit-addressable digital I/O on RX devices
are unbuffered. When used as inputs, overvoltages on these lines can cause severe
damage to the system. TDT recommends when sending digital signals into the
device, never send a signal with amplitude greater than five volts into any digital
input.
Configuring the Programmable I/O Lines
Each of the eight bit-addressable bits can be independently configured as inputs or
outputs. The digital I/O lines can be configured as inputs or outputs in groups of
eight bits – that is as byte A and byte B. Note, however, that the bytes must be
addressed as if part of a word, not as individual bytes.
Bits In A Word" in the
By default, all bits are configured as inputs. This default setting is intended to
prevent damage to equipment that might be connected to the digital I/O lines. The
user can configure the bits in the RPvdsEx configuration register. The configuration
register is also used to determine what the eight front panel Bits lights represent.
To access the bit configuration register in RPvdsEx:
1.
2. In the Set Hardware Parameters dialog box, click the Device Type box
RX6 Multifunction Processor
RPvdsEx Manual
Click the Device Setup command on the Implement menu.
and select the RX6 Multi-Function from the list.
The dialog expands to display the Device Configuration Register.
RPvdsEx Manual
RPvdsEx Manual
See "Addressing Digital
for more information.
System 3
for more
for more