E202075_HD404889 Datasheet, PDF (138/202 Pages) Renesas Technology Corp – Low-Voltage AS Microcomputers with On-Chip LCD Circuit

HD404889/HD404899/HD404878/HD404868 Series
LCD Circuit
The MCU incorporates a controller and driver that drive four common signal pins and 32 segment pins (24
segment pins in the HD404868 Series). The controller unit consists of a RAM unit that stores the display
data, a display control register (LCR), and a duty/clock control register (LMR) (figures 86-1 and 86-2).
The LCD circuit allows four different duties and LCD clocks to be controlled by the program, and also
incorporates dual-port RAM, enabling display data to be transferred to the segment signal pins
automatically without program processing. If the 32 kHz oscillator clock is designated as the LCD clock
source, LCD display is also possible in watch mode in which the system clock stops.
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