atmega32c1 ATMEL Corporation, atmega32c1 Datasheet - Page 170

• Manufacturer Part Number: atmega32c1
• Description: Atmega32m1 Automotive 8-bit Avr Microcontroller With 32k/64k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

16.2.3.2
16.2.3.3
16.2.3.4
16.2.3.5
16.2.3.6
16.2.3.7
170
ATmega32/64/M1/C1
Synchronization Segment
Propagation Time Segment
Phase Segment 1
Sample Point
Phase Segment 2
Information Processing Time
Transmission Point
Figure 16-3. CAN Bit Construction
The first segment is used to synchronize the various bus nodes.
On transmission, at the start of this segment, the current bit level is output. 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 by the receiving nodes.
This segment is used to compensate for signal delays across the network.
This is necessary to compensate for signal propagation delays on the bus line and through the
transceivers of the bus nodes.
Phase Segment 1 is used to compensate for edge phase errors.
This segment may be lengthened during re-synchronization.
The sample point is the point of time at which the bus level is read and interpreted as the value
of the respective bit. Its location is at the end of Phase Segment 1 (between the two Phase
Segments).
This segment is also used to compensate for edge phase errors.
This segment may be shortened during re-synchronization, but the length has to be at least as
long as the Information Processing Time (IPT) and may not be more than the length of Phase
Segment 1.
It is the time required for the logic to determine the bit level of a sampled bit.
Time Quantum
CAN Frame
(producer)
(producer)
(consumer)
Segments
(producer)
(producer)
Segments
SYNC_SEG
propagation
delay
SYNC_SEG
PROP_SEG
PROP_SEG
Nominal CAN Bit Time
PHASE_SEG_1
PHASE_SEG_1
PHASE_SEG_2
Sample Point
PHASE_SEG_2
7647A–AVR–02/08