Datasheet
Enhanced Serial Communications Interface (ESCI) Module
MC68HC908QB8 Data Sheet, Rev. 3
130 Freescale Semiconductor
13.8.7 ESCI Baud Rate Register
The ESCI baud rate register (SCBR) together with the ESCI prescaler register selects the baud rate for
both the receiver and the transmitter.
NOTE
There are two prescalers available to adjust the baud rate — one in the
ESCI baud rate register and one in the ESCI prescaler register.
LINT — LIN Transmit Enable
This read/write bit selects the enhanced ESCI features for the local interconnect network (LIN) protocol
as shown in Table 13-5.
LINR — LIN Receiver Bits
This read/write bit selects the enhanced ESCI features for the local interconnect network (LIN) protocol
as shown in Table 13-5.
In LIN (version 1.2 and later) systems, the master node transmits a break character which will appear
as 11.05–14.95 dominant bits to the slave node. A data character of 0x00 sent from the master might
appear as 7.65–10.35 dominant bit times. This is due to the oscillator tolerance requirement that the
slave node must be within ±15% of the master node's oscillator. Because a slave node cannot know
if it is running faster or slower than the master node (prior to synchronization), the LINR bit allows the
slave node to differentiate between a 0x00 character of 10.35 bits and a break character of 11.05 bits.
The break symbol length must be verified in software in any case, but the LINR bit serves as a filter,
preventing false detections of break characters that are really 0x00 data characters.
Bit 7654321Bit 0
Read:
LINT LINR SCP1 SCP0 R SCR2 SCR1 SCR0
Write:
Reset:00000000
R = Reserved
Figure 13-16. ESCI Baud Rate Register (SCBR)
Table 13-5. ESCI LIN Control Bits
LINT LINR M Functionality
0 0 X Normal ESCI functionality
0 1 0 11-bit break detect enabled for LIN receiver
0 1 1 12-bit break detect enabled for LIN receiver
1 0 0 13-bit generation enabled for LIN transmitter
1 0 1 14-bit generation enabled for LIN transmitter
1 1 0 11-bit break detect/13-bit generation enabled for LIN
1 1 1 12-bit break detect/14-bit generation enabled for LIN