Modules DF1 and DF2
NAI’s latest generation Differential I/O Multi-Mode Transceiver Modules are offered in two versions: the Standard Functionality (SF) module (DF1) and the Enhanced Functionality (EF) module (DF2). Both modules feature 16 individual RS422/RS485 I/O channels that are programmable for either input or output, and include extensive diagnostics. They are used on our multifunction embedded boards, SBCs, and Rugged Systems. The EF module also provides the additional features listed below.
When programmed for input, each differential channel has a selectable internal resistor (120 ohm) across its inputs. Each channel also can be programmed for fast or slow slew rates (a slow slew rate may be desirable for certain sensitive EMI-radiated transmission line applications). Status and/or interrupts can be polled/enabled for each channel to indicate transition on rising edge, transition on falling edge, or Background Built-In-Test (BIT) fault. De-bounce circuits for each channel offer a programmable time delay to eliminate false signals resulting from contact bounce commonly experienced with mechanical relays and switches. All inputs are continuously scanned.
Continuous Background Built-in-Test (BIT) status provides real-time channel health for mission-critical systems. This feature runs in the background and is transparent in normal operations. When the channels are programmed as inputs, a redundant, read-back circuit continually scans each channel to verify the input. When the channels are programmed as outputs, the read-back circuit is compared with the commanded output logic.
EF Module DF2
When the DF2 channels are programmed as inputs, the following measurement modes are available on the incoming signal:
- Mode 0: De-bounce filter
- Mode 1: High time
- Mode 2: Low time
- Mode 3: Time-stamp of all rising edges
- Mode 4: Time-stamp of all falling edges
- Mode 5: Time-stamp of all edges
- Mode 6: Count of total number of rising edges
- Mode 7: Count of total number of falling edges
- Mode 8: Count of total number of all edges
- Mode 9: Period measurement from rising edge-to-rising edge
- Mode 10: Period measurement of frequency
When the DF2 channels are programmed as outputs, the following PWM measurement modes are available:
- Mode 11: Continuous pulse generation
- Mode 12: Burst pulse generation (n-times)
- Mode 13: Multi-channel data pattern (single)
- Mode 14: Multi-channel data pattern