cp3cn17 National Semiconductor Corporation, cp3cn17 Datasheet - Page 95

• Manufacturer Part Number: cp3cn17
• Description: Reprogrammable Connectivity Processor With Can Interface
• Manufacturer: National Semiconductor Corporation

TSEG1
TSEG2
The Time Segment 1 field configures the
length of the Time Segment 1 (TSEG1). It is
not recommended to configure the time seg-
ment 1 to be smaller than 2 time quanta. (see
Table 46).
The Time Segment 2 field specifies the num-
ber of time quanta (tq) for phase segment 2
(see Table 47).
Table 46 Time Segment 1 Settings
Table 47 Time Segment 2 Settings
TSEG1[3:0]
TSEG2
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
001
010
011
100
101
110
111
Not recommended
Length of TSEG2
Length of Time
1 time quantum
10 time quanta
11 time quanta
12 time quanta
13 time quanta
14 time quanta
15 time quanta
16 time quanta
2 time quanta
3 time quanta
4 time quanta
5 time quanta
6 time quanta
7 time quanta
8 time quanta
9 time quanta
2 time quanta
3 time quanta
4 time quanta
5 time quanta
6 time quanta
7 time quanta
8 time quanta
(TSEG1)
95
15.10.8 Global Mask Register (GMSKB/GMSKX)
The GMSKB and GMSKX registers allow software to global-
ly mask, or “don’t care” the incoming extended/standard
identifier bits, RTR/XRTR and IDE. Throughout this docu-
ment, the GMSKB and GMSKX 16-bit registers are refer-
enced as a 32-bit register GMSK.
The following are the bits for the GMSKB register.
The following are the bits for the GMSKX register.
For all GMSKB and GMSKX register bits, the following ap-
plies:
0 – The incoming identifier bit must match the correspond-
1 – Accept 1 or 0 (“don’t care”) in the incoming ID bit inde-
When an extended frame is received from the CAN bus, all
GMSK bits GM[28:0], IDE, RTR, and XRTR are used to
mask the incoming message. In this case, the RTR bit in the
GMSK register corresponds to the SRR bit in the message.
The XRTR bit in the GMSK register corresponds to the RTR
bit in the message.
During the reception of standard frames only the GMSK bits
GM[28:18], RTR, and IDE are used. In this case, the
GM[28:18] bits in the GMSK register correspond to the
ID[10:0] bits in the message.
Global Mask GM[28:18] RTR IDE GM[17:0] XRTR
15
15
Extended
Standard
Frame
Frame
pendent from the corresponding bit in the message
buffer ID registers. The corresponding ID bit in the mes-
sage buffer will be overwritten by the incoming identifier
bits.
ing bit in the message buffer identifier register.
GM[28:18]
ID[28:18]
ID[10:0]
GM[14:0]
5
R/W
R/W
RTR
0
0
RTR IDE
SRR IDE
4
IDE
3
ID[17:0]
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2
GM[17:15]
Unused
1
XRTR
RTR
0
0