NEC 78K0/KD1 Series User Manual page 274

(1) Receive buffer register 6 (RXB6)
This 8-bit register stores parallel data converted by the receive shift register.
Each time 1 byte of data has been received, new receive data is transferred to this register from receive shift
register 6 (RXS6). If the data length is set to 7 bits, data is transferred as follows.
• In LSB-first reception, the receive data is transferred to bits 0 to 6 of RXB6 and the MSB of RXB6 is always 0.
• In MSB-first reception, the receive data is transferred to bits 1 to 7 of RXB6 and the LSB of RXB6 is always 0.
If an overrun error (OVE6) occurs, the receive data is not transferred to RXB6.
RXB6 can be read by an 8-bit memory manipulation instruction. No data can be written to this register.
RESET input sets this register to FFH.
(2) Receive shift register 6 (RXS6)
This register converts the serial data input to the R
RXS6 cannot be directly manipulated by a program.
(3) Transmit buffer register 6 (TXB6)
This buffer register is used to set transmit data. Transmission is started when data is written to TXB6.
This register can be read or written by an 8-bit memory manipulation instruction.
RESET input sets this register to FFH.
Cautions 1. Do not write data to TXB6 when bit 1 (TXBF6) of asynchronous serial interface transmission
status register 6 (ASIF6) is 1.
2. Do not refresh (write the same value to) TXB6 by software during a communication
operation (when bit 7 (POWER6) and bit 6 (TXE6) of asynchronous serial interface operation
mode register 6 (ASIM6) are 1 or when bit 7 (POWER6) and bit 5 (RXE6) of ASIM6 are 1).
However, if the same value is continuously transmitted in the transmission mode (POWER6
= 1 and TXE6 = 1), the same value can be written.
(4) Transmit shift register 6 (TXS6)
This register transmits the data transferred from TXB6 from the T
TXB6 immediately after TXB6 is written for the first transmission, or immediately before INTST6 occurs after one
frame was transmitted for continuous transmission. Data is transferred from TXB6 and transmitted from the T
pin at the falling edge of the internal clock.
TXS6 cannot be directly manipulated by a program.
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CHAPTER 14 SERIAL INTERFACE UART6
D6 pin into parallel data.
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Preliminary User's Manual U16315EJ1V0UD
D6 pin as serial data. Data is transferred from
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D6
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