★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 1 Functions of VDP2
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VDP2 User's Manual / Chapter 1 Functions of VDP2

■ 1.2 Address map

Two VRAMs for defining pattern name tables and character pattern data are connected to VDP2. It also has 32K bits of built-in color RAM for defining color data. In addition, the built-in register is also managed. Figure 1.2 shows an address map of VRAM, color RAM, and registers managed by VDP2.

Figure 1.2 Address map
000000H ┌──────────┐
       │ │
       │ │
       │ VRAM │
       │ │
0FFFFFH │ │ │
100000H ├──────────┤
       │ │
       │ Color RAM │
17FFFFH │ │ │
180000H ├──────────┤
       │ │
       │ Register │
       │ │
1 BFFFFH └──────────┘

● VRAM

Stores image data of scroll screens and data tables required for each function.
Read access by VDP2 always takes precedence over read / write access by CPU or DMA controller. Therefore, depending on the timing of access, the CPU or DMA controller may have a wait cycle.
Access by the CPU or DMA controller is possible in bytes, words, and longwords. However, read access by SCU-DMA should not be performed.

● Color RAM

Stores color data for sprites and scroll screens.
Also, if necessary, define the enable bit of the color calculation function in the most significant bit.
Read / write access from the CPU or DMA controller is always possible, but the image may be distorted depending on the timing of access.
Access by CPU or DMA controller is possible only in word units and long word units. It cannot be accessed in bytes.

● Register

Set each function of VDP2.
Be sure to set the value because the value is cleared to 0 in most registers after the power is turned on or reset.
Read / write access from the CPU or DMA controller is always possible, but the image may be distorted depending on the timing of access.
Access by CPU or DMA controller is possible only in word units and long word units. It cannot be accessed in bytes.

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★ HARDWARE Manual ★ VDP2 User's Manual ★ Chapter 1 Functions of VDP2
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