HT16C21
Segment Driver Outputs
The LCD drive section includes 20 segment outputs SEG0 ~ SEG19 or 16 segment outputs SEG4 ~ SEG19 which
should be connected directly to the LCD panel. The segment output signals are generated in accordance with the
multiplexed column signals and with the data resident in the display latch. The unused segment outputs should be
left open-circuit when less than 20 or 16 segment outputs are required.
Column Driver Outputs
The LCD drive section includes 4 column outputs COM0~COM3 or 8 column outputs COM0~COM7 which
should be connected directly to the LCD panel. The column output signals are generated in accordance with
the selected LCD drive mode. The unused column outputs should be left open-circuit if less than 4 or 8 column
outputs are required.
Address Pointer
The addressing mechanism for the display RAM is implemented using the address pointer. This allows the loading
of an individual display data byte, or a series of display data bytes, into any location of the display RAM. The
sequence commences with the initialization of the address pointer by the Address pointer command.
Blinker Function
The device contains versatile blinking capabilities. The whole display can be blinked at frequencies selected by
the Blink command. The blinking frequency is a subdivided ratio of the system frequency. The ratio between
the system oscillator and blinking frequencies depends on the blinking mode in which the device is operating, as
shown in the following table:
Blinking Mode
Operating Mode Ratio
0
Blinking Frequency (Hz)
0
1
2
3
Blink off
fSYS / 16384Hz
fSYS / 32768Hz
fSYS / 65536Hz
2
1
0.5
Frame Frequency
The HT16C21 device provides two frame frequencies selected with Mode set command known as 80Hz and
160Hz respectively.
Rev. 1.00
13
November 22, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
