Fujitsu MB90895 Series Hardware Manual page 516

CHAPTER 16 CAN controller
Example : When 1TQ is 1/20 bit timing at 100Kbps (1/100Kbps/20)
Condition : (resynchronous jump width is 4TQ, delay time is 50µs)
(1) Calculations of time quantum (TQ) [TQ = (PSC + 1)
Machine clock (CLK)
4MHz (0.25 µs)
8MHz (0.125 µs)
16MHz (0.0625 µs)
(4) Condition of bit timing (BT) [BT
MAchine clock (CLK)
4MHz (0.25 µs)
8MHz (0.125 µs)
16MHz (0.0625 µs)
(3) Setting of resynchronous jump width (when resynchronous jump width is 4TQ)
RSJ+1 (Division of TQ)
RSJW = (RSJ + 1)
(5) Condition of TSEG2
RSJW = (RSJ + 1)
≥
TSEG2 RSJW
≥
TSEG2 RSJW
(6) Condition of TSEG1
≥
TSEG1 Delay time + RSJW (Assuming that delaytime is 50ns)
TSEG1
(2) Calculation of bit time (BT) based or the above setting and condition
BT = SYNC_SEG + TSEG1 + TSEG2
= (1 + (TS1 + 1)+ (TS2+1))
= (3 + TS1 + TS2)
Calculating of sample point
SYNC_SEG + (TSEG1 + 1) TSEG2 + 1
(1)
(2)
(3)
(4)
(5)
SYNC_SEG
498
Figure 16.3-13 Calculation Example of Bit Timing
1 2 3
0.25 0.5 0.75
0.13 0.25 0.38
0.06 0.13 0.19
≥
8TQ]
2 4 6
1 2 3
0.5 1 1.5
1 2 3
×
TQ 0.5 1 1.5
×
TQ 1 2 3
1 2 3
0.5 1 1.5
5 (Unit: TQ)
×
TQ
×
TQ
Sample
point
16 4
80%
15 5
75%
14 6
70%
13 7
65%
12 8
60%
TSEG 1 + 1 TSEG2 + 1
Sample point
×
CLK]
Division of input clock (PSC+1)
4 5 6 7 8
1 1.25 1.5 1.75 2 2.25
0.5 0.63 0.75 0.88 1 1.13
0.25 0.31 0.38 0.44 0.5 0.56
8TQ
8 10 12 14 16
4 5 6 7 8
2 2.5 3 3.5 4 4.5
4 (Unit: TQ)
(Unit: us)
2
4 (Unit: TQ)
4 (Unit: TQ)
2 (Unit: us)
× ≥
2 + 4TQ 5TQ
1 2
1
667 500
2 500 400
3 400 333
4 333 286
5 286 250
6 250 222
7 222 200
8 200 182
TSEG1 + 1
9 182 167
10 167 154
11
154 143
12 143 133
13 133 125
14 125 118
15 118 111
16 111 105
(Unit: µs)
9 10 11 12 13 14
2.5 2.75 3 3.25 3.5
1.25 1.38 1.5 1.63 1.75
0.63 0.69 0.75 0.81 0.88
(Unit: µs)
18 20 22 24 26 28
9 10 11 12 13 14
5 5.5 6 6.5 7
(Unit: Kbps)
TSEG2 + 1
3 4 5 6 7
222
400 333 286 250
333 286 250 222 200
286 250 222 200 182
250 222 200 182 167
222 200 182 167 154
200 182 167 154 143
182 167 154 143 133
167 154 143 133 125
154 143 133 125 118
143 133 125 118 111
125 118 111 105
133
125 118 111 105 100
118 111 105 100 95.2
111 105 100 95.2 90.9
105 100 95.2 90.9 87
100 95.2 90.9 87 83.3
(1) (2) (3) (4) (5)
15
3.75
1.88
0.94
30
15
7.5
8
200
182
167
154
143
133
125
118
111
105
100
95.2
90.9
87
83.3
80