Uart Power Down And Wake-Up - Holtek BS86DH12C Manual

BS86DH12C
High Voltage Touch A/D Flash MCU with HVIO
USR Register
Transmitter Empty
Flag TXIF
Transmitter Idle
Flag TIDLE
Receiver Overrun
Flag OERR
ADDEN
Receiver Data
Available RXIF
0
WAKE
RX Pin
Wake-up
1
UCR2 Register
Address Detect Mode
Setting the Address Detect Mode bit, ADDEN, in the UCR2 register, enables this special mode. If
this bit is enabled then an additional qualifier will be placed on the generation of a Receiver Data
Available interrupt, which is requested by the RXIF flag. If the ADDEN bit is enabled, then when
data is available, an interrupt will only be generated, if the highest received bit has a high value. Note
that the URE and EMI interrupt enable bits must also be enabled for correct interrupt generation.
This highest address bit is the 9th bit if BNO=1 or the 8th bit if BNO=0. If this bit is high, then
the received word will be defined as an address rather than data. A Data Available interrupt will be
generated every time the last bit of the received word is set. If the ADDEN bit is not enabled, then
a Receiver Data Available interrupt will be generated each time the RXIF flag is set, irrespective of
the data last bit status. The address detect mode and parity enable are mutually exclusive functions.
Therefore if the address detect mode is enabled, then to ensure correct operation, the parity function
should be disabled by resetting the parity enable bit PREN to zero.

UART Power Down and Wake-up

When the UART clock (f
module are shutdown. If the UART clock (f
the transmission will be paused until the UART clock source derived from the microcontroller is
activated. In a similar way, if the MCU enters the IDLE or SLEEP Mode while receiving data, then
the reception of data will likewise be paused. When the MCU enters the IDLE or SLEEP Mode,
note that the USR, UCR1, UCR2, transmit and receive registers, as well as the BRG register will not
be affected. It is recommended to make sure first that the UART data transmission or reception has
been finished before the microcontroller enters the IDLE or SLEEP mode.
Rev. 1.00
UCR2 Register
0
TEIE
1
UART Interrupt
TIIE
0
Request Flag
1
URF
0
RIE
1
0
0
1
1
RX7 if BNO=0
RX8 if BNO=1
UART Interrupt Structure
Bit 9 if BNO=1,
ADDEN
Bit 8 if BNO=0
0
0
1
0
1
1
ADDEN Bit Function
) is off, the UART will cease to function, and all clock sources to the
H
) is off while a transmission is still in progress, then
H
151
URE EMI
Interrupt signal
to MCU
UART Interrupt
Generated
√
√
×
√
October 26, 2018