
Rev. 1.00
140
October 26, 2018
Rev. 1.00
141
October 26, 2018
BS86DH12C
High Voltage Touch A/D Flash MCU with HVIO
BS86DH12C
High Voltage Touch A/D Flash MCU with HVIO
Bit 2
RXIF
: Receive TXR_RXR data register status
0: TXR_RXR data register is empty
1: TXR_RXR data register has available data
The RXIF flag is the receive data register status flag. When this read only flag is “0”,
it indicates that the TXR_RXR read data register is empty. When the flag is “1”, it
indicates that the TXR_RXR read data register contains new data. When the contents
of the shift register are transferred to the TXR_RXR register, an interrupt is generated
if RIE=1 in the UCR2 register. If one or more errors are detected in the received word,
the appropriate receive-related flags NF, FERR, and/or PERR are set within the same
clock cycle. The RXIF flag will eventually be cleared when the USR register is read
with RXIF set, followed by a read from the TXR_RXR register, and if the TXR_RXR
register has no more new data available.
Bit 1
TIDLE
: Transmission idle
0: Data transmission is in progress (Data being transmitted)
1: No data transmission is in progress (Transmitter is idle)
The TIDLE flag is known as the transmission complete flag. When this read only
flag is “0”, it indicates that a transmission is in progress. This flag will be set high
when the TXIF flag is “1” and when there is no transmit data or break character being
transmitted. When TIDLE is equal to “1”, the TX pin becomes idle with the pin state
in logic high condition. The TIDLE flag is cleared by reading the USR register with
TIDLE set and then writing to the TXR_RXR register. The flag is not generated when
a data character or a break is queued and ready to be sent.
Bit 0
TXIF
: Transmit TXR_RXR data register status
0: Character is not transferred to the transmit shift register
1: Character has transferred to the transmit shift register (TXR_RXR data register is
empty)
The TXIF flag is the transmit data register empty flag. When this read only flag is “0”,
it indicates that the character is not transferred to the transmitter shift register. When
the flag is “1”, it indicates that the transmitter shift register has received a character
from the TXR_RXR data register. The TXIF flag is cleared by reading the UART
status register (USR) with TXIF set and then writing to the TXR_RXR data register.
Note that when the TXEN bit is set, the TXIF flag bit will also be set since the transmit
data register is not yet full.
• UCR1 Register
The UCR1 register together with the UCR2 register are the two UART control registers that are used
to set the various options for the UART function, such as overall on/off control, parity control, data
transfer bit length etc. Further explanation on each of the bits is given below:
Bit
7
6
5
4
3
2
1
0
Name
UARTEN
BNO
PREN
PRT
STOPS
TXBRK
RX8
TX8
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
W
POR
0
0
0
0
0
0
x
0
“x”: unknown
Bit 7
UARTEN
: UART function enable control
0: Disable UART. TX and RX pins are in a floating state
1: Enable UART. TX and RX pins function as UART pins
The UARTEN bit is the UART enable bit. When this bit is equal to “0”, the UART will
be disabled and the RX pin as well as the TX pin will be in a floating state. When the
bit is equal to “1” the UART will be enabled and the TX and RX pins will function as
defined by the TXEN and RXEN enable control bits.
When the UART is disabled, it will empty the buffer so any character remaining in
the buffer will be discarded. In addition, the value of the baud rate counter will be
reset. If the UART is disabled, all error and status flags will be reset. Also the TXEN,
RXEN, TXBRK, RXIF, OERR, FERR, PERR and NF bits will be cleared, while the