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4.1.2
Character Generator (CG)
(1) Features of each character generator
1 Internal character generator
The internal character generator is effective for a minimum display system consisting of the
S1D13700, display memory (data RAM), LCD unit, single-chip MPU, and a power supply. Moreover,
because the internal character generator includes CMOS mask ROM, it is very advantageous when low
power consumption is desired.
Character font
• 5 x 7 dots (See Section 4.4.1 "Character Fonts (Internal CG)" on page 81.)
Number of characters
• JIS-compliant 160 characters
Combined use with CG RAM possible (up to 64 characters)
Processing of the character field space part
The S1D13700 automatically sets spaces in the range of 8 x 16 dots maximum.
2 CG RAM
CG RAM as a graphic generator allows any desired character font to be defined by the user. Moreover,
because the MPU can alter address mapping in the display memory space can be altered as required,
unused portions of display memory can be effectively utilized.
Character font
• 8 x 8 dots maximum <M2 = 0>
• 8 x 16 dots maximum <M2 = 1>
Number of characters
• Up to 64 characters when used in combination with CG ROM
• Up to 256 characters when used only in F000H to FFFFH
Defined area of CG RAM in the display memory space
• CG RAM (maximum 64 characters) that can be used in combination with CG ROM can be allo-
cated to any desired contiguous addresses.
• CG RAM (maximum 65 characters or more) that cannot be used in combination with CG ROM
must be allocated to fixed addresses F000H through FFFFH. When 193 characters or more must
be defined in this fixed address area, set SAG = F000H and M1 = 0.
(2) Concept of how character generator banks are set
Because the character codes handled by the S1D13700 consist of 8 bits, the number of discrete characters
that can be displayed simultaneously is limited to a maximum of 256. The CGRAM ADR command can
be used to switch banks, however, thus extending the number of usable characters as shown below.
Basic CG space
(8 x 16 pixels x 256
characters max)
S1D13700 Technical Manual
CG ROM
(5 x 7 pixels x 160
characters max)
CG RAM
(8 x 16 pixels x 64cha)
MO=0
MO=1
CG RAM
(8 x 16 pixels x 256
characters max)
EPSON
4: FUNCTION DESCRIPTION
CG RAM n
CG RAM 3
CG RAM 2
CG RAM 1
SAG
CG RAM n
CG RAM 3
CG RAM 2
CG RAM 1
SAG
47
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