CP3BT26 Datasheet, PDF (136/278 Pages) National Semiconductor (TI) – Reprogrammable Connectivity Processor with Bluetooth-R, USB, and CAN Interfaces

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 59).
Table 59 Time Segment 1 Settings
TSEG1[3:0]
Length of Time
(TSEG1)
19.10.8 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.
15
5
4
32
0
0000
Not recommended
GM[28:18]
RTR IDE GM[17:15]
0001
2 time quanta
0
R/W
0010
3 time quanta
0011
0100
4 time quanta
5 time quanta
The following are the bits for the GMSKX register.
0101
0110
0111
1000
6 time quanta
15
7 time quanta
8 time quanta
9 time quanta
GM[14:0]
0
R/W
10
XRTR
1001
1010
1011
1100
1101
1110
1111
10 time quanta
11 time quanta
12 time quanta
13 time quanta
14 time quanta
15 time quanta
16 time quanta
The Time Segment 2 field specifies the num-
ber of time quanta (tq) for phase segment 2
(see Table 60).
Table 60 Time Segment 2 Settings
TSEG2
000
Length of TSEG2
1 time quantum
For all GMSKB and GMSKX register bits, the following ap-
plies:
0 – The incoming identifier bit must match the correspond-
ing bit in the message buffer identifier register.
1 – Accept 1 or 0 (“don’t care”) in the incoming ID bit inde-
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.
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.
001
2 time quanta
Global Mask GM[28:18] RTR IDE GM[17:0] XRTR
010
3 time quanta
011
4 time quanta
Standard
Frame
ID[10:0] RTR IDE
Unused
100
5 time quanta
Extended
Frame
ID[28:18] SRR IDE ID[17:0] RTR
101
6 time quanta
110
7 time quanta
111
8 time quanta
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