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Chapter 11 Serial Interface 0, 1
XI - 46
Operation
Judgement of Break Status Reception
Reception at break status can be judged. If all received data from start bit to stop bit is "0", the SCnBRKF
flag of the SCnMD2 register is set and regard the break status. The SCnBRKF flag is set at generation
of the reception complete interrupt SCnRIRQ.
Table 11-3-21 Reception Error Source of UART Serial Interface
Sequence Communication
It is possible to transfer continuously. If data is set to the transmission data buffer TXBUFn during
communication, the transmission buffer empty flag SCnTEMP is set to continue the communication,
automatically. In this case, there is no pause on communication. Data should be set to TXBUFn after
data is loaded to the inside shift register before the communication complete interrupt SC0TIRQ is
generated.
Also, this LSI has an automatic data transfer function ATC1 that can be one of an activation factor. At
activation by ATC1, data can be transfered up to 255 bytes, continuously. In this case, there is a commu-
nication blank ; up to 18 machine cycles + 3.5 bit data length. For an activation by ATC1, refer to chapter
15. automatic transfer controller, transfer mode 6 to 9.
Reception Error
At reception , there are 3 types of error ; overrun error, parity error and framing error. Reception error can
be determined by the SCnORE, SCnPEK, SCnFEF flag of the SCnMD3 register. Even one of those
errors is detected, the SCnERE flag of the SCnMD3 register is set to "1". The SCnPEK, the SCnFEF
flags in recepption error flag are renewed at generation of the reception complete interrupt SCnRIRQ.
The SCnORE flag is holded the status unless data of RXBUFn is read out. The judgements of the
received error flag should be operated until the next communication is finished. The communication
operation does not have any effect on those error flags . Table 11-3-21 shows the list of reception error
source.
Flag Error
SCnORE Overrun error
at fixed to 0 when parity bit is "1"
at fixed to 1 when parity bit is "0"
odd parity
The total of "1" of parity bit and character bit is
even.
even parity
The total of "1" of parity bit and character bit is
odd.
SCnFEF Framing error Stop bit is not detected.
Error source
Next data is received before reading the receive buffer.
SCnPEK Parity error