CHAPTER 11 SERIAL INTERFACE UART6
Preliminary User’s Manual U16898EJ1V0UD
203
(h) SBF transmission
When the device is incorporated in LIN, the SBF (Synchronous Break Field) transmission control function is
used for transmission. For the transmission operation of LIN, see Figure 11-1 LIN Transmission
Operation.
An SBF length that is a low-level width of 13 bits or more is set by bits 4 to 2 (SBL62 to SBL60) of
asynchronous serial interface control register 6 (ASICL6). If the output width needs to be adjusted more
accurately, use the baud rate value of the normal UART transmission function.
[Setting method]
Transmit 00H by setting the number of character bits of the data to 8 bits and the parity bit to 0 parity or even
parity. This enables a low-level transmission of a data frame consisting of 10 bits (1 bit (start bit) + 8 bits
(character bits) + 1 bit (parity bit)).
Adjust the baud rate value to adjust this 10-bit low level to the targeted 13-bit SBF length (SBL62, SBL61,
SBL60 = 1, 0, 1).
Example If LIN is to be transmitted under the following conditions
•
Base clock of UART6 = 5 MHz (set by clock selection register 6 (CKSR6))
•
Target baud rate value = 19200 bps
To realize the above baud rate value, the length of a 13-bit SBF is as follows if the baud rate generator
control register 6 (BRGC6) is set to 130.
•
13-bit SBF length = 0.2
µ
s
×
130
×
2
×
13 = 676
µ
s
To realize a 13-bit SBF length in 10 bits, set a value 1.3 times the targeted baud rate to BRGC6. In this
example, set 169 to BRGC6. The transmission length of a 10-bit low level in this case is as follows, and
matches the 13-bit SBF length.
•
10-bit low-level transmission length = 0.2
µ
s
×
169
×
2
×
10 = 676
µ
s
If the number of bits set by BRGC6 runs short, adjust the number of bits by setting the base clock of
UART6.
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