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FUNCTIONAL DESCRIPTION
2.11 CRT display function
The vertical position can specify 128-step positions (4 scanning lines per step) for each block by setting
values "00
" to "7F
16
16
addresses to 00E1
, 00E2
16
Vertical Position Register n
b7 b6 b5 b4 b3 b2 b1 b0
Fig. 2.11.6 Vertical position register n (addresses 00E1
The horizontal direction is common to both blocks, and can specify 64-step display positions (4 T
T
: oscillation cycle for display) by setting values "00
C
register (address 00E0
Figure 2.11.7 shows the horizontal position register.
Horizontal Position Register
b7 b6 b5 b4 b3 b2 b1 b0
Fig. 2.11.7 Horizontal position register (address 00E0
2-76
" to bits 0 to 6 of the vertical position registers (the blocks 1 and 2 are assigned to
respectively). Figure 2.11.6 shows the vertical position registers.
16
Vertical position register n (CV1,CV2) (n = 1 and 2) [Addresses 00E1
B
0
Vertical display start positions
to
(CV1 : CV10 to CV16)
6
(CV2 : CV20 to CV26)
7
Nothing is assigned. This bit is a write disable bit.
When this bit is read out, the value is "0."
).
16
Horizontal position register (HR) [Address 00E0
B
0
Horizontal display start
to
positions (HR0 to HR5)
5
6, 7
Nothing is assigned. These bits are write disable bits.
When thses bits are read out, the values are "0."
7220 Group User's Manual
Name
Functions
128 steps (00
16
and 00E2
16
" to "3F
" to bits 0 to 5 of the horizontal position
16
16
16
Name
Functions
64 steps (00
to 3F
16
)
16
00E2
]
16,
16
After reset
R W
to 7F
)
Indeterminate
R W
16
0
R —
)
16
]
After reset R W
)
0
R W
16
0
R —
per step,
C
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