7220 Datasheet, PDF (103/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

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 “0016” to “7F16” to bits 0 to 6 of the vertical position registers (the blocks 1 and 2 are assigned to
addresses to 00E116, 00E216 respectively). Figure 2.11.6 shows the vertical position registers.
Vertical Position Register n
b7 b6 b5 b4 b3 b2 b1 b0
Vertical position register n (CV1,CV2) (n = 1 and 2) [Addresses 00E116, 00E216]
B
Name
Functions
0 _{Vertical display start positions}
to _{(CV1 : CV10 to CV16)}
6 _{(CV2 : CV20 to CV26)}
128 steps (0016 to 7F16)
7 Nothing is assigned. This bit is a write disable bit.
When this bit is read out, the value is “0.”
After reset R W
Indeterminate R W
0
R—
Fig. 2.11.6 Vertical position register n (addresses 00E116 and 00E216)
The horizontal direction is common to both blocks, and can specify 64-step display positions (4 TC per step,
TC: oscillation cycle for display) by setting values “0016” to “3F16” to bits 0 to 5 of the horizontal position
register (address 00E016).
Figure 2.11.7 shows the horizontal position register.
Horizontal Position Register
b7 b6 b5 b4 b3 b2 b1 b0
Horizontal position register (HR) [Address 00E016]
B
Name
Functions
0 Horizontal display start
to
5
positions (HR0 to HR5)
64 steps (0016 to 3F16)
6, 7 Nothing is assigned. These bits are write disable bits.
When thses bits are read out, the values are “0.”
After reset R W
0 RW
0 R—
Fig. 2.11.7 Horizontal position register (address 00E016)
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7220 Group User’s Manual