SENT (Single Edge Nibble Transmission)

Concurrent's SENT protocol I/O card is ideal for use in high-performance hardware-in-the-loop (HIL) simulation and test applications. The PCIe card support the Single Edge Nibble Transmission (SENT) protocol as specified by SAE J2716. The card provides 12 input channels and 12 output channels. The output channels generate SENT output waveforms depending on how the channel is configured. For each SENT input or output channel, there are three ways to construct the messages:

• Fast channel
  This is the basic mode of operation of the SENT protocol. Fast channel data is always transmitted/received when the channel is configured. This other format - Short and Enhanced - use status bits of the fast channel to encode additional information.
• Signals values are conveyed using the data nibbles.
• The number of data nibbles can be configured between 1 (4 bits) and a maximum of 6 nibbles.

• Short Format
  Serial data is transmitted (bit by bit) in bit 2 (of the Status and Communication nibble) of consecutive messages from the transmitter. Serial data is communicated in a 16-bit sequence.
• The 16-bit message consists of a 4-bit Message ID nibble, 2 nibbles of data, and a CRC checksum nibble.
• All 16 frames must be successfully received (no errors, calibration pulse variation, data nibble CRC error, etc.) for the serial value to be received.

• Enhanced Format
  Serial data is transmitted in bit 2 and bit 3 of the Status and Communication nibble. Serial data is communicated in a 18-bit sequence. The serial message frame contains 12 bits of payload data. Two different configurations can be chosen determined by the configuration bit:
• 12-bit data and 8-bit message ID
• 16-bit data and 4-bit message ID
• All 18 frames must be successfully received (no errors, calibration pulse variation, data nibble CRC error, etc.) for the serial value to be received.

Configuration for a channel:

• Number of nibbles: number of nibbles for a channel, varies from 1 to 6.
• Pause Pulse:
  • Transmitter (Output): An extra pulse which is transmitted after the checksum nibble. e.g. this pulse can be used to create a SENT transmission with a constant number of clock ticks.
  • Receiver (Input): For a system with pause pulse, during synchronization and re-synchronization of reception, if calibration pulses are detected one immediately following the other, the first calibration pulse shall be ignored as it may be a pause pulse with duration match the calibration pulse range.
• Legacy CRC-4: CRC checksum is implemented as a series of shift left by 4 (multiply by 16) followed by a 256 array look-up.
• Tick Length (Ouput only): Length of clock tick (in microseconds)
• Frame Length (Output only): Only enabled when Pause Pulse is enabled.

Configuration for Fast Channel:

• Specify start nibble and number of nibbles to add a nibble field.

Configuration for Short Format

• Specify a ID to add ID for a short format message, ID is 4 bit.

Configuration for Enhanced Format

• Specify a ID to add ID for a enhanced format message, ID can be 4 bit or 8 bit.
• In enhanced format, the channel can be configured to sent multiple ID's in succession. Add the ID's to the enhanced format branch. The Same ID can be repeated within the sequence. The ID's will be sent in the order in which they appear in the list. You can reorder the list by selecting a ID and clicking on the move-up / move-down arrow buttons.
  The sequence of ID's is sent continuously and is restarted with the first ID after the last ID has been sent.

Pause / Resume data output

• This can be mapped to a digital output variable to pause / resume outputting channel data.
  When the value of the mapped variable is != 0, the channel is paused. When this control is not mapped, the channel can only be paused via the use of the corresponding SENT API function call.