LM3S2110-IQN20-A0 Luminary Micro, Inc., LM3S2110-IQN20-A0 Datasheet - Page 358

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

Controller Area Network (CAN) Module
14.4.15.2 Example for Bit Timing at Low Baud Rate
14.5
Table 14-4. CAN Register Map
358
Offset
0x00C
0x000
0x004
0x008
0x010
Name
CANCTL
CANSTS
CANERR
CANBIT
CANINT
tProp 600 ns = 6 × tq
tSJW 100 ns = 1 × tq
tTSeg1 700 ns = tProp + tSJW
tTSeg2 200 ns = Information Processing Time + 1 × tq
tSync-Seg 100 ns = 1 × tq
bit time 1000 ns = tSync-Seg + tTSeg1 + tTSeg2
tolerance for CAN_CLK 0.39 % =
In the above example, the concatenated bit time parameters are (2-1)3&(7-1)4&(1-1)2&(1-1)6, and
CANBIT is programmed to 0x1600.
In this example, the frequency of CAN_CLK is 2 MHz, BRP is 1, and the bit rate is 100 Kbps.
tq 1 ms = 2 × tCAN_CLK
delay of bus driver 200 ns
delay of receiver circuit 80 ns
delay of bus line (40m) 220 ns
tProp 1 ms = 1 × tq
tSJW 4 ms = 4 × tq
tTSeg1 5 ms = tProp + tSJW
tTSeg2 4 ms = Information Processing Time + 3 × tq
tSync-Seg 1 ms = 1 × tq
bit time 10 ms = tSync-Seg + tTSeg1 + tTSeg2
tolerance for CAN_CLK 1.58 % =
In this example, the concatenated bit time parameters are (4-1)3&(5-1)4&(4-1)2&(2-1)6, and CANBIT
is programmed to 0x34C1.
Controller Area Network Register Map
Table 14-4 on page 358 lists the registers. All addresses given are relative to the CAN base address
of:
■
All accesses are on word (32-bit) boundaries.
min(PB1,PB2)/ 2 x (13 x bit time - PB2) =
4us/ 2 x (13 x 10us - 4us)
CAN0: 0x4004.0000
min(PB1,PB2)/ 2 × (13 x bit time - PB2) =
0.1us/ 2 x (13x 1us - 2us)
Type
R/W
R/W
R/W
RO
RO
0x0000.0001
0x0000.0000
0x0000.0000
0x0000.2301
0x0000.0000
Reset
Preliminary
Description
CAN Control
CAN Status
CAN Error Counter
CAN Bit Timing
CAN Interrupt
November 29, 2007
page
See
361
363
366
367
369