Mouse Position Register; Crtc Registers; Crtc Address Register Pointer; Mouse Position Register Format - Digital Equipment VAXstation I Service Manual

PROGRAMMING INFORMATION'
Table 2·3: Cursor X Position Bits
+· - - - - - - -+- - - - - - - -+- - - • - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -+
j
BITS
I
ACCESS
!
DESCRIPTION I
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<15:10> (not used)
<09:00> WRITE Cursor X position in pixels.
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2.1.3 Mouse Position Register
This register contains mouse X and
·y
position values. The values
are counted up or down, in proportion to the direction and amount
of mouse movement.
15 08 07
00
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-+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-+
Y COUNT X COUNT
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ADDRESS
=
CSR BASE
+
4
Figure 2-3: Mouse Position Register Format
Table 2·4: Mouse Position Register Bits
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BITS ACCESS DESCRIPTION
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<15:08> READ Mouse Y position count.
<07:00> READ Mouse X position count.
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-+
2.1.4 CRTC Registers
2.1.4.l CRTC Address Register Pointer - This register points to
the one of 17 internal CRTC registers (Table 2-6), that is to
receive the data contained in the CRTC Data Register (described
below). It also contains three status bits (Figure 2-4 and Table
2 - 5) •
2-4