Rev. 1.10
132
November 04, 2019
Rev. 1.10
133
November 04, 2019
HT45F5Q-3
Battery Charger Flash MCU
HT45F5Q-3
Battery Charger Flash MCU
that the UUSR, UUCR1, UUCR2, transmit and receive registers, as well as the UBRG 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.
The UART function contains a receiver RX pin wake-up function, which is enabled or disabled by
the UWAKE bit in the UUCR2 register. If this bit, along with the UART mode selection bit, UMD,
the UART enable bit, UREN, the receiver enable bit, URXEN and the receiver interrupt bit, URIE,
are all set when the UART clock (f
H
) is off, then a falling edge on the RX pin will trigger an RX pin
wake-up UART interrupt. Note that as it takes certain system clock cycles after a wake-up, before
normal microcontroller operation resumes, any data received during this time on the RX pin will be
ignored.
For a UART wake-up interrupt to occur, in addition to the bits for the wake-up being set, the global
interrupt enable bit, EMI, and the USIM interrupt enable bit, USIME, must be set. If the EMI and
USIME bits are not set then only a wake up event will occur and no interrupt will be generated.
Note also that as it takes certain system clock cycles after a wake-up before normal microcontroller
resumes, the USIM interrupt will not be generated until after this time has elapsed.
Software Controlled LCD Driver
The device has the capability of driving external LCD panels. The common pins for LCD driving,
SCOM0~SCOM3, are pin-shared with certain pin on the I/O ports. The LCD signals (COM) are
generated using the application program.
LCD Operation
An external LCD panel can be driven using the device by configuring the I/O pins as common pins.
The LCD driver function is controlled using the SCOMC register which in addition to controlling
the overall on/off function also controls the R-type bias current on the SCOMn pins. This enables
the LCD COM driver to generate the necessary V
DD
/2 voltage levels for LCD 1/2 bias operation.
The SCOMEN bit in the SCOMC register is the overall master control for the LCD driver. The
LCD SCOMn pin is selected to be used for LCD driving by the corresponding pin-shared function
selection bits. Note that the Port Control register does not need to first setup the pins as outputs to
enable the LCD driver operation.
SCOM operating current
SCOM0~SCOM3
Pin-shared selection bits
SCOMEN
V
DD
/2
V
DD
Software Controlled LCD Driver Structure
LCD Bias Current Control
The LCD COM driver enables a range of selections to be provided to suit the requirement of the
LCD panel which are being used. The bias current choice is implemented using the ISEL1 and
ISEL0 bits in the SCOMC register.