HT69F240 Datasheet, PDF (131/172 Pages) Holtek Semiconductor Inc – I/O 8-Bit Flash MCU with LED/LCD Driver

HT69F240
I/O 8-Bit Flash MCU with LED/LCD Driver
UCR2 Register
The UCR2 register is the second of the UART control registers and serves several purposes. One
of its main functions is to control the basic enable/disable operation if the UART Transmitter and
Receiver as well as enabling the various UART interrupt sources. The register also serves to control
the baud rate speed, receiver wake-up function enable and the address detect function enable.
Further explanation on each of the bits is given below:
Bit
7
6
5
4
3
2
1
0
Name TXEN RXEN BRGH ADDEN WAKE
RIE
TIIE
TEIE
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7
Bit 6
Bit 5
Bit 4
TXEN: UART Transmitter enable control
0: UART Transmitter is disabled
1: UART Transmitter is enabled
The bit named TXEN is the Transmitter Enable Bit. When this bit is equal to "0", the
transmitter will be disabled with any pending data transmissions being aborted. In
addition the buffers will be reset. In this situation the TX pin can be used as an I/O or
other pin-shared functional pin. If the TXEN bit is equal to "1" and the UARTEN bit is
also equal to 1, the transmitter will be enabled and the TX pin will be controlled by the
UART. Clearing the TXEN bit during a transmission will cause the data transmission
to be aborted and will reset the transmitter. If this situation occurs, the TX pin can be
used as an I/O or other pin-shared functional pin.
RXEN: UART Receiver enable control
0: UART Receiver is disabled
1: UART Receiver is enabled
The bit named RXEN is the Receiver Enable Bit. When this bit is equal to "0", the
receiver will be disabled with any pending data receptions being aborted. In addition
the receiver buffers will be reset. In this situation the RX pin can be used as an I/O or
other pin-shared functional pin. If the RXEN bit is equal to "1" and the UARTEN bit
is also equal to 1, the receiver will be enabled and the RX pin will be controlled by the
UART. Clearing the RXEN bit during a reception will cause the data reception to be
aborted and will reset the receiver. If this situation occurs, the RX pin can be used as
an I/O or other pin-shared functional pin.
BRGH: Baud Rate speed selection
0: Low speed baud rate
1: High speed baud rate
The bit named BRGH selects the high or low speed mode of the Baud Rate Generator.
This bit, together with the value placed in the baud rate register, BRG, controls the
baud rate of the UART. If the bit is equal to 0, the low speed mode is selected.
ADDEN: Address detect function enable control
0: Address detection function is disabled
1: Address detection function is enabled
The bit named ADDEN is the address detection function enable control bit. When this
bit is equal to 1, the address detection function is enabled. When it occurs, if the 8^th
bit, which corresponds to RX7 if BNO=0, or the 9^th bit, which corresponds to RX8 if
BNO=1, has a value of "1", then the received word will be identified as an address,
rather than data. If the corresponding interrupt is enabled, an interrupt request will be
generated each time the received word has the address bit set, which is the 8^th or 9^th
bit depending on the value of the BNO bit. If the address bit known as the 8^th or 9^th
bit of the received word is "0" with the address detection function being enabled, an
interrupt will not be generated and the received data will be discarded.
Rev. 1.20
131
March 25, 2015