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Epson Research and Development
Vancouver Design Center
S1D13503
Programming Notes and Examples
X18A-G-002-06
Issue Date: 01/01/30
4 DISPLAY MEMORY MODELS
This section includes a concise description of the Display Start Address Registers, followed by a description of display
memory. Afterwards examples are provided, illustrating how to calculate the display memory model for a given display
resolution and color/gray level mode. Once this model is calculated, examples on programming the Display Start Address
Registers are provided.
4.1 Registers
Register bits discussed in this section are highlighted.
bit 1
Memory Interface
This bit selects between the 8-bit or 16-bit memory interface. When this bit = 0, the 16-bit memory inter-
face is selected. When this bit = 1, the 8-bit memory interface is selected. If 16-bit bus interface (VD0 = 1
on RESET) or 256 color mode (AUX[03] bits 2-1 = 11) is selected, the Memory Interface bit is forced to 0
internally (16-bit). This bit goes low on RESET.
AUX[06] bits 7-0 Screen 1 Display Start Address Bits [15:0]
AUX[07] bits 7-0 These 16 bits determine the Screen 1 Display Start Address. In an 8-bit memory configuration these bits
set the 16-bit start address (i.e., byte access). In a 16-bit memory configuration these are the 16 most sig-
nificant bits of a 17-bit start address (i.e., word access).
Note
The absolute address into display memory is determined by the Memory Mapping
Address which is set by the reset state of VD13 - VD15.
The Screen 1 Display Start Address is the memory address corresponding to the first displayed pixel (top
left corner). In a dual panel configuration, screen 1 refers to the upper half of the display. While in a single
panel configuration, screen 1 refers to the first screen of the Split Screen Display feature where two differ-
ent images (screen 1 and screen 2) can be displayed at the same time on one display.
AUX[01] Mode Register 0
I/O address = 0001b, Read/Write.
DISP
Panel
Mask
XSCL
LCDE
Gray Shade /
Color
LCD Data
Width Bit 0
Memory
Interface
RAMS
AUX[06] Screen 1 Display Start Address Register (LSB)
I/O address = 0110b, Read/Write.
Screen 1
Display Start
Addr
Bit 7
Screen 1
Display Start
Addr
Bit 6
Screen 1
Display Start
Addr
Bit 5
Screen 1
Display Start
Addr
Bit 4
Screen 1
Display Start
Addr
Bit 3
Screen 1
Display Start
Addr
Bit 2
Screen 1
Display Start
Addr
Bit 1
Screen 1
Display Start
Addr
Bit 0
AUX[07] Screen 1 Display Start Address Register (MSB)
I/O address = 0111b, Read/Write.
Screen 1
Display
Start Addr
Bit 15
Screen 1
Display
Start Addr
Bit 14
Screen 1
Display
Start Addr
Bit 13
Screen 1
Display
Start Addr
Bit 12
Screen 1
Display
Start Addr
Bit 11
Screen 1
Display
Start Addr
Bit 10
Screen 1
Display
Start Addr
Bit 9
Screen 1
Display
Start Addr
Bit 8
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