ST7781
15. Window Address Function
The window address function enables writing display data consecutively in a rectangular area (a window address area)
made on the internal DRAM. The window address area is made by setting the horizontal address register (star: HAS[7:0],
end HEA[7:0] bits) and the vertical address register(start: VSA[8:0], end: VEA[8:0] bits) The AM bits sets the transition
direction of RAM address(either increment or decrement). These bits enable the ST7781 to write data including image data
consecutively not taking data wrap positions into account.
The window address area must be made within the GRAN address map area. Also, DRAM address bits (RAM address set
register) must be an address within the window address area.
[Window address setting area]
(Horizontal direction) 00H ≦ HSA[7:0] ≦ HEA[7:0] ≦ ”EF”H
(Vertical direction) 00H ≦VSA[8:0] ≦ VEA[8:0] ≦ ”13F”H
[RAM address, AD (an address within a window address area)]
(RAM address) HSA[7:0] ≦AD[7:0] ≦HEA[7:0]
VSA[8:0] ≦AD[15:8] ≦VEA[8:0]
DRAM Address Map
0"0000"h
0"00EF”h
Window Address Area
2010h
2110h
203Fh
213Fh
4F10h
4F3Fh
I”3F00"h
Window address setting area
I"3FEF"h
HSA[7 :0 ] = 1 0 h , HSA[7 :0 ] = 3 Fh , I/D = 1 (increment)
VSA[8 :0 ] = 2 0 h , VSA[8 :0 ] = 4 Fh , AM = 0 (horizontal writing )
Fig.15.1 DRAM Access Window Map
Ver. 1.7
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