s908qc16vdse Freescale Semiconductor, Inc, s908qc16vdse Datasheet - Page 144

• Manufacturer Part Number: s908qc16vdse
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Enhanced Serial Communications Interface (ESCI) Module
13.8.6 ESCI Data Register
The ESCI data register (SCDR) is the buffer between the internal data bus and the receive and transmit
shift registers. Reset has no effect on data in the ESCI data register.
R7/T7:R0/T0 — Receive/Transmit Data Bits
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.
LINT — LIN Transmit Enable
LINR — LIN Receiver Bits
144
Reading SCDR accesses the read-only received data bits, R7:R0.
Writing to SCDR writes the data to be transmitted, T7:T0.
This read/write bit selects the enhanced ESCI features for the local interconnect network (LIN) protocol
as shown in
This read/write bit selects the enhanced ESCI features for the local interconnect network (LIN) protocol
as shown in
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.
Reset:
Reset:
Read:
Write:
Read:
Write:
Do not use read-modify-write instructions on the ESCI data register.
There are two prescalers available to adjust the baud rate — one in the
ESCI baud rate register and one in the ESCI prescaler register.
Table
Table
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 4
13-5.
13-5.
LINT
Bit 7
Bit 7
R7
T7
R
0
Figure 13-16. ESCI Baud Rate Register (SCBR)
= Reserved
Figure 13-15. ESCI Data Register (SCDR)
LINR
R6
T6
6
6
0
SCP1
R5
T5
5
5
0
Unaffected by reset
SCP0
NOTE
NOTE
R4
T4
4
4
0
R3
T3
R
3
3
0
SCR2
R2
T2
2
2
0
SCR1
R1
T1
1
1
0
Freescale Semiconductor
SCR0
Bit 0
Bit 0
R0
T0
0