DS_6612_001
78M6612 Data Sheet
3.6 Connecting LCDs
The 78M6612 has a LCD controller on-chip capable of controlling static or multiplexed LCDs. Figure 31
shows the basic connection for a LCD.
78M6612
LCD
segments
commons
Figure 31: Connecting LCDs
The LCD segment pins can be organized in the following groups:
1. Seventeen pins are dedicated LCD segment pins (SEG0 to SEG13, SEG16 to SEG18).
2. Four pins are dual-function pins CKTEST/SEG19, E_RXTX/SEG38, E_TCLK/SEG33, and
E_RST/SEG32.
3. Fourteen pins are available as combined DIO and segment pins SEG24/DIO4 to SEG31/DIO11,
SEG34/DIO14 to SEG37/DIO17, SEG39/DIO19, and SEG40/DIO20.
4. The QFN-68 package adds an additional combination pin, SEG41/DIO21. Also adds two additional
LCD segment pins, SEG13 and SEG14.
The split between DIO and LCD use of the combined pins is controlled with the DIO register LCD_NUM.
LCD_NUM can be assigned any number between 0 and 18. The first dual-purpose pin to be allocated as
LCD is SEG41/DIO21 (on the 68-pin QFN package). Thus if LCD_NUM=2, SEG41 and SEG 40 will be
configured as LCD. The remaining SEG39 to SEG24 will be configured as DIO19 to DIO4. DIO1 and
DIO2 are always available, if not used for UART1.
Note that pins CKTEST/SEG19, E_RXTX/SEG38, E_TCLK/SEG33, and E_RST/SEG32 are not affected
by LCD_NUM.
Table 46 and Table 47 show the allocation of DIO and segment pins as a function of LCD_NUM for both
package types.
Rev. 1.2
67
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
