
CHAPTER 15 ASYNCHRONOUS SERIAL INTERFACE A (UARTA)
User’s Manual U16541EJ4V0UD
492
(1) UARTAn control register 0 (UAnCTL0)
The UAnCTL0 register is an 8-bit register used to specify the UARTAn operation.
(2) UARTAn control register 1 (UAnCTL1)
The UAnCTL1 register is an 8-bit register used to select the input clock for the UARTAn.
(3) UARTAn control register 2 (UAnCTL2)
The UAnCTL2 register is an 8-bit register used to control the baud rate for the UARTAn.
(4) UARTAn option control register 0 (UAnOPT0)
The UAnOPT0 register is an 8-bit register used to control serial transfer for the UARTAn.
(5) UARTAn status register (UAnSTR)
The UAnSTRn register consists of flags indicating the error contents when a reception error occurs. Each one
of the reception error flags is set (to 1) upon occurrence of a reception error and is reset (to 0) by reading the
UAnSTR register.
(6) UARTAn receive shift register
This is a shift register used to convert the serial data input to the RXDAn pin into parallel data. Upon reception
of 1 byte of data and detection of the stop bit, the receive data is transferred to the UAnRX register.
This register cannot be manipulated directly.
(7) UARTAn receive data register (UAnRX)
The UAnRX register is an 8-bit register that holds receive data. When 7 characters are received, 0 is stored in
the highest bit (when data is received LSB first).
In the reception enabled status, receive data is transferred from the UARTAn receive shift register to the
UAnRX register in synchronization with the completion of shift-in processing of 1 frame.
Transfer to the UAnRX register also causes the reception complete interrupt request signal (INTUAnR) to be
output.
(8) UARTAn transmit shift register
The transmit shift register is a shift register used to convert the parallel data transferred from the UAnTX
register into serial data.
When 1 byte of data is transferred from the UAnTX register, the shift register data is output from the TXDAn pin.
This register cannot be manipulated directly.
(9) UARTAn transmit data register (UAnTX)
The UAnTX register is an 8-bit transmit data buffer. Transmission starts when transmit data is written to the
UAnTX register. When data can be written to the UAnTX register (when data of one frame is transferred from
the UAnTX register to the UARTAn transmit shift register), the transmission enable interrupt request signal
(INTUAnT) is generated.