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XI - 17
Chapter 11
Serial Interface 0
Operation
nReception Buffer Empty Flag
When SC0TIRQ is generated, data is automatically stored to RXBUF0 from the internal shift register. If
data is stored to the shift register RXBUF0, the reception buffer empty flag SC0REMP of the SC0MD3
register is set to "1". This indicates that the received data is going to read out. SC0REMP is cleared to "0"
by reading out the data of RXBUF0.
nTransmission Buffer Empty Flag
If any data is set to TXBUF0 again, during communication (after setting data to TXBUF0 and before the
communication complete interrupt SC0TIRQ is generated), the transmission buffer empty flag
SC0TEMP of the SC0MD3 register is set to "1". This indicates that the next transmission data is going to
be loaded. Data is loaded to the inside shift register from TXBUF0 by generation of SC0TIRQ, and the
next transfer is started as SC0TEMP is cleared to "0".
nOverrun Error and Error Monitor Flag
If, after reception complete, the next data has been already received before reading out of the data of the
received data buffer RXBUF0, overrun error is generated and the SC0ORE flag of the SC0MD3 register
is set to "1". And at the same time, the error monitor flag SC0RE is set to indicate that error is occurred
on reception. The SC0ORE flag holds the status unless the data of RXBUF0 is read out. SC0ERE is
cleared as SC0ORE flag is cleared. These error flags have no effect on communication operation.
nReception BUSY Flag
When any data is set to TXBUF0 or when the SC0SBIS flag of the SC0MD1 register is "1" as start
condition is input, the SC0RBSY flag of the SC0MD3 register is set to "1". And, on the generation of the
communication complete interrupt SC0TIRQ, the flag is cleared to "0". And, during continuous commu-
nication, the SC0RBSY flag is always set. If the transmission buffer empty flag SC0TEMP is cleared to
"0" as the communication complete interrupt SC0TIRQ is generated, SC0RBSY is cleared to "0". If the
SC0SBIS flag is set to "0" during communication, the SC0RBSY flag is cleared to "0".
nTransmission BUSY Flag
When any data is set to TXBUF0 or when the SC0SBOS flag of the SC0MD1 register is "1" as start
condition is input, the SC0TBSY flag of the SC0MD3 register is set to "1". And, on the generation of the
communication complete interrupt SC0TIRQ, the flag is cleared to "0". And, during continuous commu-
nication, the SC0TBSY falg is always set. If the transmission buffer empty flag SC0TEMP is cleared to
"0" as the communication complete interrupt SC0TIRQ is generated, SC0TBSY is cleared to "0". If the
SC0SBOS flag is set to "0" during communication, the SC0TBSY flag is cleared to "0".