TC1796
Peripheral Units (Vol. 2 of 2)
Controller Area Network (MultiCAN) Controller
User’s Manual 22-89 V2.0, 2007-07
MultiCAN, V2.0
Bit Timing Analysis Modes
CFCOV 23 rwh CAN Frame Counter Overflow Flag
Flag CFCOV is set upon a frame counter overflow (transition
from FFFF
H
to 0000
H
). In bit timing analysis mode, CFCOV
is set upon an update of CFC. An interrupt request is
generated if CFCIE = 1.
0
B
No overflow has occurred since the last (most recent)
clearance of the flag.
1
B
An overflow has occurred since the last (most recent)
clearance of the flag.
CFCOV must be cleared by software.
0 21,
[31:24]
r Reserved
Read as 0; should be written with 0.
Table 22-8 Bit Timing Analysis Modes (CFMOD = 10)
CFSEL Measurement
000
B
Whenever a dominant edge (transition from 1 to 0) is monitored on the
receive input, the time (measured in clock cycles) between this edge and the
most recent dominant edge is stored in CFC.
001
B
Whenever a recessive edge (transition from 0 to 1) is monitored on the
receive input, the time (measured in clock cycles) between this edge and the
most recent dominant edge is stored in CFC.
010
B
Whenever a dominant edge is received as a result of a transmitted dominant
edge, the time (clock cycles) between both edges is stored in CFC.
011
B
Whenever a recessive edge is received as a result of a transmitted recessive
edge, the time (clock cycles) between both edges is stored in CFC.
100
B
Whenever a dominant edge that qualifies for synchronization is monitored on
the receive input, the time (measured in clock cycles) between this edge and
the most recent sample point is stored in CFC.
101
B
With each sample point, the time (measured in clock cycles) between the
start of the new bit time and the start of the previous bit time is stored in
CFC[11:0]. Additional information is written to CFC[15:12] at each sample
point:
CFC[15]: Transmit value of actual bit time
CFC[14]: Receive sample value of actual bit time
CFC[13:12]: CAN bus information (see Table 22-9)
111
B
Reserved; do not use this combination.
Field Bits Type Description
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