NEC 78K0 Series User Manual page 375

(g) Noise filter of receive data
The RXD6 signal is sampled with the base clock output by the prescaler block.
If two sampled values are the same, the output of the match detector changes, and the data is sampled as
input data.
Because the circuit is configured as shown in Figure 15-21, the internal processing of the reception operation
is delayed by two clocks from the external signal status.
Base clock
R D6/P14
X
(h) SBF transmission
When the device is incorporated in LIN, the SBF (Synchronous Break Field) transmission control function is
used for transmission.
Operation.
When bit 7 (POWER6) of asynchronous serial interface mode register 6 (ASIM6) is set to 1, the T
outputs high level. Next, when bit 6 (TXE6) of ASIM6 is set to 1, the transmission enabled status is entered,
and SBF transmission is started by setting bit 5 (SBTT6) of asynchronous serial interface control register 6
(ASICL6) to 1.
Thereafter, a low level of bits 13 to 20 (set by bits 4 to 2 (SBL62 to SBL60) of ASICL6) is output. Following
the end of SBF transmission, the transmission completion interrupt request (INTST6) is generated and
SBTT6 is automatically cleared. Thereafter, the normal transmission mode is restored.
Transmission is suspended until the data to be transmitted next is written to transmit buffer register 6 (TXB6),
or until SBTT6 is set to 1.
1
T D6
X
INTST6
SBTT6
Remark T D6: T D6 pin (output)
X X
INTST6: Transmission completion interrupt request
SBTT6: Bit 5 of asynchronous serial interface control register 6 (ASICL6)
CHAPTER 15 SERIAL INTERFACE UART6
Figure 15-21. Noise Filter Circuit
Internal signal A
In Q
For the transmission operation of LIN, see Figure 15-1
Figure 15-22. SBF Transmission
2 3 4 5 6
Preliminary User's Manual U17260EJ3V1UD
In
Match detector LD_EN
7 8 9 10 11 12
Internal signal B
Q
LIN Transmission
D6 pin
X
13 Stop
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