SENT transmits data in 4-bit nibbles between two falling edges, hence the name “Single Edge Nibble”. Timing of the SENT bus is measured in ticks, with each tick typically 3 μs wide. Each nibble starts with a logic-low period of at least 5 ticks, followed by a variable-length logic-high period representing the encoded data value. A 0000 binary data value is represented by a logic-high duration of 12 ticks. A 0001 binary data value is represented by a logic-high duration of 13 ticks, and so on, up to a 1111 binary data value is represented by a logic-high duration of 27 ticks.

• Electrical signaling: signal line, a +5V supply voltage line, and a ground
• Signal levels: Low < 0.5V and high > 4.1V
• Data rate: up to 30 kb/s

Single Edge Nibble encodes four bits in a single pulse.

The SENT bus is a single-ended, ground-referenced signal. Although the oscilloscope can acquire and decode the bus using standard single-ended probing, the signal fidelity and noise immunity may be improved by using differential probing.

On Tektronix oscilloscopes equipped with SENT decoding and triggering, pressing the front panel Bus button enables you to define inputs to the scope as a bus. To enable the oscilloscope to decode the packet data, you enter some basic parameters regarding your specific SENT implementation.

Parameters for setting up SENT decoding and triggering on a 5 Series MSO.

Bus triggering tells the oscilloscope to capture all the input signals based on a specified bus event. That event will be positioned at the trigger point. For the SENT bus, the 5 Series MSO can be set up to trigger on:

• Start of Packet
• Fast channel data
• Pause Pulse
• Error

Similar to bus triggers, the oscilloscope can also search through all its aqcuired data, for bus conditions that match specified values.

Setup to trigger on status value of 0000 binary, fast channel 1 data value 0x27F, and fast channel 2 data value 0xC72.