Infineon C166 Series User Manual

AP29000
Connecting C166 and C500 Microcontroller to CAN
The Controller Area Network (CAN)
Application Note 18 V 1.0, 2004-02
3.3.3.3 Interframe Space
Interframe Space separates a preceeding frame (of whatever type) from a following
Data or Remote Frame. Interframe space is composed of at least 3 recessive bits,
these bits are termed the Intermission. This time is provided to allow nodes time for
internal processing before the start of the next message frame. After the Intermission,
the bus line remains in the recessive state (Bus Idle) until the next transmission starts.
3.4 The Nominal Bit Time
One bit cell (i.e. one high or low pulse of the NRZ code) is constructed from four
segments. Each segment is in turn constructed from an integer multiple of Time
Quanta. The Time Quantum is the smallest discrete timing resolution used by a CAN
node. A bit time, and therefore by definition also the bit rate, is selected by
programming the Bit Timing Logic (BTL) to select the width of the Time Quanta and the
number of Time Quanta in the various segments. The nominal bit time with its
segments (according to CAN Spec ISO11898, 1993) is shown in figure 5.
Figure 5 Partition of bit time
The SYNC_SEG (Synchronisation Segment) is used to synchronise the various bus
nodes. If there is a bit state change between the previous bit and the current bit then
the bus state change is expected to occur within this segment. The length of this
segment is always 1 Time Quantum (1 BTL cycle).
Propagation
Segment
(PROP_SEG)
Synchronisation
Segment
(SYNC_SEG)
Nominal bit time
Sample Point
Phase Buffer
Segment 1
(PHASE_SEG1)
Phase Buffer
Segment 2
(PHASE_SEG2)

Infineon C166 Series Specifications

General

Brand	Infineon
Model	C166 Series
Category	Microcontrollers
Language	English