Memory Control Registers; Display Size Registers X And Y (Dsrx, Dsry) - Hitachi HD64411 Q2 User Manual

5 . 4

Memory Control Registers

The memory control registers comprise eleven 16-bit registers related to the UGM (unified
graphics memory) configuration, mapped onto addresses (A10–A1) H'008 to H'012.
5 . 4 . 1

Display Size Registers X and Y (DSRX, DSRY)

Bit: 15 14
DSRX — —
Initial value: — —
Read/Write: — —
Bit: 15 14
DSRY — —
Initial value: — —
Read/Write: — —
Note: * Value is retained.
Display size registers X and Y (DSRX, DSRY) are 16-bit readable/writable registers that specify
the size of the display screen. The number of dots in the horizontal direction is set in DSRX, and
the number of dots in the vertical direction in DSRY.
The set value of bits DSX (H'0000 to H'03FF) corresponds to the number of horizontal dots, from
1 to 1024.
The set value of bits DSY (H'0000 to H'01FF) corresponds to the number of vertical dots, from 1
to 512.
Bits 15 to 10 of DSRX and bits 15 to 9 of DSRY are reserved. Only 0 should be written to these
bits (a read will return an undefined value).
DSRX bits DSX9 to DSX0 and DSRY bits DSY8 to DSY0 retain their values in a reset.
13 12 11 10 9
— — — — DSX
— — — — *
— — — — R/W
13 12 11 10 9
— — — — —
— — — — —
— — — — —
8 7 6 5 4
DSX DSX DSX DSX DSX
* * * * *
R/W R/W R/W R/W R/W
8 7 6 5 4
DSY DSY DSY DSY DSY
* * * * *
R/W R/W R/W R/W R/W
3 2 1 0
DSX DSX DSX DSX
* * * *
R/W R/W R/W R/W
3 2 1 0
DSY DSY DSY DSY
* * * *
R/W R/W R/W R/W
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