Mitsubishi Electric Apricot LS Pro, Hardware Technical Reference

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Memory and I/O Usage
Chapter 4
Chapter 6
Appendix A
Appendix C
Pr
eface
Chapter 4Chapter 5
5/22 LS PRO HARDWARE TECHNICAL REFERENCE
CRT Controller The CRT controller registers handle the data associated with the CRT. The registers
registers are accessed by using index and data registers. To access a register, first write to the
index register with the index of the data register to be accessed, then read or write
to the data register.
Register Address
CRT controller index register 03B4h (RWM)
03D4h (RWC)
CRT controller data register 03B5h (RWM)
03D5h (RWC)
R - read
W - write
M - monochrome
C - colour
The following table shows the index and the registers which can be accessed via the
index.
Register Index
Horizontal total 00h
Horizontal display enable end 01h
Start horizontal blanking 02h
End horizontal blanking 03h
Start horizontal retrace pulse 04h
End horizontal retrace 05h
Vertical total 06h
Overflow 07h
Preset row scan 08h
Maximum scan line 09h
Cursor start 0Ah
Cursor end 0Bh
Start address high 0Ch
Start address low 0Dh
Cursor location high 0Eh
Cursor location low 0Fh
Vertical retrace start 10h
Vertical retrace end 11h
Vertical display enable end 12h
Offset 13h
Underline location 14h
Start vertical blank 15h
End vertical blank 16h
CRTC mode control 17h
Line compare 18h
These are standard VGA registers and are not described in further detail here.