LM3S2965-IQC20-A0T Luminary Micro, Inc., LM3S2965-IQC20-A0T Datasheet - Page 412

• Manufacturer Part Number: LM3S2965-IQC20-A0T
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

Controller Area Network (CAN) Module
16.4.15.2 Example for Bit Timing at Low Baud Rate
16.5
Table 16-4. CAN Register Map
412
Offset
0x000
0x004
0x008
Name
CANCTL
CANSTS
CANERR
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
“Controller Area Network Register Map” on page 412 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
CAN1: 0x4004.1000
min(PB1,PB2)/ 2 × (13 x bit time - PB2) =
0.1us/ 2 x (13x 1us - 2us)
Type
R/W
R/W
RO
0x0000.0001
0x0000.0000
0x0000.0000
Reset
Preliminary
Description
CAN Control
CAN Status
CAN Error Counter
June 04, 2007
page
See
415
417
420