Datasheet

78K0/Kx2-L CHAPTER 14 SERIAL INTERFACE UART6
R01UH0028EJ0400 Rev.4.00 479
Sep 27, 2010
(i) SBF reception
When the device is used in LIN communication operation, the SBF (Synchronous Break Field) reception control
function is used for reception. For the reception operation of LIN, refer to Figure 14-2 LIN Reception
Operation.
Reception is enabled when bit 7 (POWER6) of asynchronous serial interface operation mode register 6 (ASIM6)
is set to 1 and then bit 5 (RXE6) of ASIM6 is set to 1. SBF reception is enabled when bit 6 (SBRT6) of
asynchronous serial interface control register 6 (ASICL6) is set to 1. In the SBF reception enabled status, the
R
XD6 pin is sampled and the start bit is detected in the same manner as the normal reception enable status.
When the start bit has been detected, reception is started, and serial data is sequentially stored in the receive
shift register 6 (RXS6) at the set baud rate. When the stop bit is received and if the width of SBF is 11 bits or
more, a reception completion interrupt request (INTSR6) is generated as normal processing. At this time, the
SBRF6 and SBRT6 bits are automatically cleared, and SBF reception ends. Detection of errors, such as OVE6,
PE6, and FE6 (bits 0 to 2 of asynchronous serial interface reception error status register 6 (ASIS6)) is
suppressed, and error detection processing of UART communication is not performed. In addition, data transfer
between receive shift register 6 (RXS6) and receive buffer register 6 (RXB6) is not performed, and the reset
value of FFH is retained. If the width of SBF is 10 bits or less, an interrupt does not occur as error processing
after the stop bit has been received, and the SBF reception mode is restored. In this case, the SBRF6 and
SBRT6 bits are not cleared.
Figure 14-25. SBF Reception
1. Normal SBF reception (stop bit is detected with a width of more than 10.5 bits)
RXD6
SBRT6
/SBRF6
INTSR6
1234567891011
2. SBF reception error (stop bit is detected with a width of 10.5 bits or less)
R X D6
SBRT6
/SBRF6
INTSR6
12345678910
“0”
Remark RXD6: RXD6 pin (input)
SBRT6: Bit 6 of asynchronous serial interface control register 6 (ASICL6)
SBRF6: Bit 7 of ASICL6
INTSR6: Reception completion interrupt request