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Chapter 9 Precautions
Notes on using - are as follows.
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● VDP1 in general
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- Rotation readout of the frame buffer is prohibited during normal, high-resolution, HDTV, and double-dense interlace.
- Only the drawing frame buffer can be accessed from the CPU.
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System register
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- DMA access to system registers is prohibited. Be sure to use word access.
- Be sure to set the system register after turning on the power.
- Be sure to set the unused bits of the system register to 0.
- Be sure to set DIE = 0 when rotating the frame buffer. Rotation readout with double-dense interlace is prohibited.
- Please note that an undefined surface is displayed for one frame immediately after changing the DIE bit.
- When changing TVM bit, it is necessary to mask the frame buffer. When changing, one frame of undefined surface is displayed.
- Please set FCM = 0 and FCT = 0 for double dense interlace. Field switching is possible only at 1/60 seconds.
- Set the erase light area so that (upper left coordinate XA) <(lower right coordinate XC) and (upper left coordinate YA) ≤ (lower right coordinate YC).
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Command
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- The local coordinates must be set after turning on the power.
- The settable range of clipping coordinates is from (0, 0) to (1023, 511).
- The clipping coordinate range is (upper left coordinate XA) ≤ (lower right coordinate XC) and (upper left coordinate YA) ≤ (lower right coordinate YC).
- Set the appropriate value for clipping according to the screen mode set by the TVM bit.
- The user clipping area must be set inside the system clipping area. It can be set on the same line.
- The upper left coordinate of the system clipping area is fixed to (0, 0) by hardware.
- Set unused bits in the word you are using to 0 in the command table.
- Calls within a command subroutine (call, jump call, skip call) are prohibited.
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