HT46CU66 HOLTEK [Holtek Semiconductor Inc], HT46CU66 Datasheet - Page 38

• Manufacturer Part Number: HT46CU66
• Description: A/D Type 8-Bit MCU with LCD
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

Rev. 1.20
UCR2 register
The UCR2 register is the second of the two UART
control registers and serves several purposes. One of
its main functions is to control the basic enable/dis-
able operation of 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 enable and the address
detect enable.
Further explanation on each of the bits is given below:
TEIE
This bit enables or disables the transmitter empty
interrupt. If this bit is equal to 1 when the transmit-
ter empty TXIF flag is set, due to a transmitter
empty condition, the UART interrupt request flag
will be set. If this bit is equal to 0 the UART inter-
rupt request flag will not be influenced by the condi-
tion of the TXIF flag.
TIIE
This bit enables or disables the transmitter idle in-
terrupt. If this bit is equal to 1 when the transmitter
idle TIDLE flag is set, the UART interrupt request
flag will be set. If this bit is equal to 0 the UART in-
terrupt request flag will not be influenced by the
condition of the TIDLE flag.
RIE
This bit enables or disables the receiver interrupt. If
this bit is equal to 1 when the receiver overrun
OERR flag or receive data available RXIF flag is
set, the UART interrupt request flag will be set. If
this bit is equal to 0 the UART interrupt will not be
influenced by the condition of the OERR or RXIF
flags.
WAKE
This bit enables or disables the receiver wake-up
function. If this bit is equal to 1 and if the MCU is in
the Power Down Mode, a low going edge on the RX
input pin will wake-up the device. If this bit is equal
38
to 0 and if the MCU is in the Power Down Mode,
any edge transitions on the RX pin will not wake-up
the device.
ADDEN
The ADDEN bit is the address detect mode bit.
When this bit is 1 the address detect mode is en-
abled. When this occurs, if the 8th bit, which corre-
sponds to RX7 if BNO=0, or the 9th bit, which
corresponds to RX8 if BNO=1, has a value of 1
then the received word will be identified as an ad-
dress, rather than data. If the corresponding inter-
rupt is enabled, an interrupt request will be
generated each time the received word has the ad-
dress bit set, which is the 8 or 9 bit depending on the
value of BNO. If the address bit is 0 an interrupt
will not be generated, and the received data will be
discarded.
BRGH
The BRGH bit selects the high or low speed mode
of the Baud Rate Generator. This bit, together with
the value placed in the BRG register, controls the
Baud Rate of the UART. If this bit is equal to 1 the
high speed mode is selected. If the bit is equal to 0
the low speed mode is selected.
RXEN
The RXEN bit 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 addi-
tion the buffer will be reset. In this situation the RX
pin can be used as a general purpose I/O pin. If the
RXEN bit is equal to 1 the receiver will be enabled
and if the UARTEN bit is equal to 1 the RX pin will
be controlled by the UART. Clearing the RXEN bit
during a transmission will cause the data reception
to be aborted and will reset the receiver. If this oc-
curs, the RX pin can be used as a general purpose
I/O pin.
HT46RU66/HT46CU66
October 2, 2007