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22.5 Display Memory
The S1C17704 has a built-in 576-byte display memory located from address 0x80000 to address 0x8055f. The
memory bit allocation to the COM/SEG pins will change according to the conditions below.
(1) Drive duty (1/32 or 1/16)
(2) SEG pin assignments (normal or reverse)
(3) COM pin assignments (normal or reverse)
Figures 22.5.1 and 22.5.2 show the correspondence between the display memory bits and the COM/SEG pins for
each duty selection.
When a display memory bit is set to 1, the corresponding pixel on the LCD panel goes on; when it is set to 0, the
pixel goes off. As it is a RAM, the display memory allows bit-unit control using logical operation (read-modify-write)
instructions.
In the 576-byte display memory area, addresses unused for display can be used as general-purpose read/write
memory.
Address
Bit
(upper 16 bits)
0x00 ···
0x0f
D0
D1
D2
D3
0x800∗∗
D4
D5
D6
D7
D0
D1
D2
D3
0x801∗∗
D4
D5
D6
D7
D0
D1
D2
D3
0x802∗∗
D4
D5
D6
D7
D0
D1
D2
D3
0x803∗∗
D4
D5
D6
D7
D0
D1
D2
D3
0x804∗∗
D4
D5
D6
D7
D0
D1
D2
D3
0x805∗∗
D4
D5
D6
D7
SEGREV = 1
SEG0
···
SEG15
SEGREV = 0
SEG55
···
SEG40
S1C17704 TECHNICAL MANUAL
Address (lower 8 bits)
0x10 ···
0x1f
0x20 ···
0x2f
Display area
SEG16
···
SEG31
SEG32
···
SEG47
SEG48
SEG39
···
SEG24
SEG23
···
SEG8
SEG7
Figure 22.5.1 Display Memory Map (for 1/32 duty)
0x30 ··· 0x37
0x38 ··· 0x47
0x48 ···
Unused area
(general-purpose memory)
···
SEG55
···
SEG0
EPSON
22 LCD DRIVER (LCD)
COMREV
COMREV
0x5f
0x60 ···
0xff
= 1
COM0
COM31
COM1
COM30
COM2
COM29
COM3
COM28
COM4
COM27
COM5
COM26
COM6
COM25
COM7
COM24
COM8
COM23
COM9
COM22
COM10
COM21
COM11
COM20
COM12
COM19
COM13
COM18
COM14
COM17
COM15
COM16
COM16
COM15
COM17
COM14
COM18
COM13
COM19
COM12
COM20
COM11
COM21
COM10
COM22
COM9
COM23
COM8
Not
COM24
COM7
implemented
COM25
COM6
COM26
COM5
COM27
COM4
COM28
COM3
COM29
COM2
COM30
COM1
COM31
COM0
= 0
22-7
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