LM3S2110-IQN20-A0 Luminary Micro, Inc., LM3S2110-IQN20-A0 Datasheet - Page 367

• Manufacturer Part Number: LM3S2110-IQN20-A0
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

CAN Bit Timing (CANBIT)
CAN0 base: 0x4004.0000
Offset 0x00C
Type R/W, reset 0x0000.2301
November 29, 2007
Reset
Reset
Type
Type
Bit/Field
31:15
14:12
11:8
7:6
reserved
RO
RO
31
15
0
0
Register 4: CAN Bit Timing (CANBIT), offset 0x00C
This register is used to program the bit width and bit quantum. Values are to be programmed to the
system clock frequency. This register is write-enabled by the CCE and INIT bits in the CANCTL
register.
With a CAN module clock (CAN_CLK) of 8 MHz, the register reset value of 0x230 configures the
CAN for a bit rate of 500 Kbps.
R/W
RO
30
14
0
0
reserved
TSeg2
TSeg1
Name
SJW
TSeg2
R/W
RO
29
13
0
1
R/W
RO
28
12
0
0
R/W
RO
Type
27
11
R/W
R/W
R/W
0
0
RO
R/W
RO
26
10
0
0
TSeg1
0x0000
Reset
0x2
0x3
0x0
R/W
RO
25
0
9
1
Preliminary
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Time Segment after Sample Point
0x00-0x07: The actual interpretation by the hardware of this value is
such that one more than the value programmed here is used.
So, for example, a reset value of 0x2 defines that there is 3(2+1) bit
time quanta defined for Phase_Seg2 (see Figure 14-2 on page 355).
The bit time quanta is defined by BRP.
Time Segment Before Sample Point
0x00-0x0F: The actual interpretation by the hardware of this value is
such that one more than the value programmed here is used.
So, for example, the reset value of 0x3 defines that there is 4(3+1) bit
time quanta defined for Phase_Seg1 (see Figure 14-2 on page 355).
The bit time quanta is define by BRP.
(Re)Synchronization Jump Width
0x00-0x03: The actual interpretation by the hardware of this value is
such that one more than the value programmed here is used.
During the start of frame (SOF), if the CAN controller detects a phase
error (misalignment), it can adjust the length of TSeg2 or TSeg1 by the
value in SJW. So the reset value of 0 adjusts the length by 1 bit time
quanta.
R/W
RO
24
0
8
1
reserved
R/W
RO
23
0
7
0
SJW
R/W
RO
22
0
6
0
R/W
RO
21
0
5
0
R/W
RO
20
0
4
0
LM3S2110 Microcontroller
R/W
RO
19
0
3
0
BRP
R/W
RO
18
0
2
0
R/W
RO
17
0
1
0
R/W
RO
16
0
0
1
367