Slave LIN Interface Controller (SLIC) Module
MC68HC908QL4 MC68HC908QL3 MC68HC908QL2 Data Sheet, Rev. 4
164
Freescale Semiconductor
delay values (cutoff values) are shown in the frequency and time domains. Note that
Table 14-7
shows
the filter performance under ideal conditions.
When switching between a low-speed (< 4800 bps) to a high-speed (> 40000 bps) LIN message, the
master node must allow a minimum idle time of eight bit times (of the slowest bit rate) between the
messages. This prevents a valid message at another frequency from being detected as an invalid
message.
Table 14-6. Maximum LIN Bit Rates for High-Speed Operation Due to Digital Receive Filter
SLIC
Clock
(MHz)
Maximum LIN
Bit Rate for ±1.5%
SLIC Accuracy
(for Master-Slave
Communication
(Bits / Second)
DIGITAL RX FILTER
NOT CONSIDERED
Maximum LIN
Bit Rate with
Digital RX Filter
Set to
÷
4
(Bits / Second)
Maximum LIN
Bit Rate with
Digital RX Filter
Set to
÷
3
(Bits / Second)
Maximum LIN
Bit Rate with
Digital RX Filter
Set to
÷
2
(Bits / Second)
Maximum LIN
Bit Rate with
Digital RX Filter
Set to
÷
1
(Bits / Second)
THESE PRESCALERS
NOT RECOMMENDED FOR
HIGH-SPEED LIN OPERATION
8
120,000
120,000
(1)
1. Bit rates over 120,000 bits per second are not recommended for LIN communications, as physical layer delay between the
TX and RX pins can cause the stop bit of a byte to be mis-sampled as the last data bit. This could result in a byte framing
error.
120,000
(1)
120,000
(1)
120,000
(1)
6.4
96,000
100,000
120,000
(1)
120,000
(1)
120,000
(1)
4.8
72,000
75,000
100,000
120,000
(1)
120,000
(1)
4
60,000
62,500
83,333
120,000
(1)
120,000
(1)
3.2
48,000
50,000
66,667
100,000
120,000
(1)
2.4
36,000
37,500
50,000
75,000
120,000
(1)
2
30,000
31,250
41,667
62,500
120,000
(1)
Table 14-7. Digital Receive Filter Absolute Cutoff (Ideal Conditions)
SLIC
Clock
(MHz)
Digital RX Filter
Set to
÷
4
Digital RX Filter
Set to
÷
3
Digital RX Filter
Set to
÷
2
Digital RX Filter
Set to
÷
1
Max.
Bit Rate
(Bits /
Sec)
Min Pulse
Width
Allowed
(
μ
s)
Max.
Bit Rate
(Bits /
Sec)
Min Pulse
Width
Allowed
(
μ
s)
Max.
Bit Rate
(Bits /
Sec)
Min Pulse
Width
Allowed
(
μ
s)
Max.
Bit Rate
(Bits /
Sec)
Min Pulse
Width
Allowed
(
μ
s)
8
125,000
8.0
166,667
6.0
250,000
4.0
500,000
2.0
6.4
100,000
10.0
133,333
7.5
200,000
5.0
400,000
2.5
4.8
75,000
13.3
100,000
10.0
150,000
6.7
300,000
3.3
4
62,500
16.0
83,333
12.0
125,000
8.0
250,000
4.0
3.2
50,000
20.0
66,667
15.0
100,000
10.0
200,000
5.0
2.4
37,500
26.7
50,000
20.0
75,000
13.3
150,000
6.7
2
31,250
32.0
41,667
24.0
62,500
16.0
125,000
8.0