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CHAPTER 17 LCD CONTROLLER/DRIVER
User’s Manual U14701EJ3V0UD
17.4 LCD Display RAM
The LCD display data and the LCD blinking select bits corresponding to LCD display data are mapped to addresses
FA00H to FA27H. The lower 4 bits of each of these addresses are an LCD display data area, and the higher 4 bits
are an LCD blinking select bit area. The LCD blinking select bits correspond to the LCD display data (i.e., LCD blinking
select bit 0 corresponds to bit 4 of the LCD display data, bit 1 to bit 5, bit 2 to bit 6, and bit 3 to bit 7). The addresses
and capacity of the area that can be used for LCD display differs depending on the product, as follows:
μ
PD780316, 780318:
FA00H to FA17A (24 bytes)
μ
PD780326, 780328:
FA00H to FA1FH (32 bytes)
μ
PD780336, 780338, 78F0338: FA00H to FA27H (40 bytes)
The data stored to the LCD display data area can be displayed on the LCD panel.
For example, bit 3 (shaded portion in Figure 17-8) of address FA01H is output to pin S1 at the timing of COM3.
The LCD blinking select bit is used to blink the corresponding segment by setting 1 to the bit to blink, and 1 to
bit 3 (BLON) of LCD display mode register 3 (LCDM3). In this case, however, the display data of the corresponding
segment must be 1.
Figure 17-8 shows the relationship between the LCD display data, contents of the blinking select bits, and segment/
common output signals.
The area not used for display can be used as a normal RAM area.
Figure 17-8. Relationship Between LCD Display Data, Contents of Blinking Select Bits,
and Segment/Common Output Signals (4-Time Division)
Caution The higher 4 bits (LCD blinking select bit area) of each address, FA00H to FA27H, correspond
to the lower 4 bits (LCD display data area). When the LCD does not blink, therefore, be sure to
clear the corresponding bit in the blinking select bit area to 0.
S0
S1
S2
S38
S39
S31
S23
FA00H
FA01H
FA02H
Address
Bit 7
Bit 6
LCD blinking select bit area
LCD display data area
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
COM3
COM2
COM1
COM0
SCOM0
FA26H
FA27H
FA1FH
FA17H
Example:
The LCD blinking select bit
corresponding to bit 0 at
address FA00H is bit 4 at
address FA00H.