Table of Contents
Advertisement
5 . 4 . 5
Work Area Start Address Register (WSAR)
Bit:
15
14
—
—
—
—
Initial value:
Read/Write:
—
—
Note: * Value is retained.
The work area start address register (WSAR) is a 16-bit readable/writable register that specifies the
memory area to be used as a work area. Only the upper bits (A22 to A16) of the start physical
address of the work area are set in the WSAH field.
The work area varies depending on the installed memory and the screen size. Some sample
calculations are shown below (the work area is the same for 16-bit/pixel and 8-bit/pixel modes).
1. Work coordinate system memory capacity for 320 × 240 screen size
512 pixels × 256 lines = 131,072 bits: 131,072 bits/8 bits/1024 = 16 kB
2. Work coordinate system memory capacity for 640 × 240 screen size
1024 pixels × 256 lines = 262,144 bits: 262,144 bits/8 bits/1024 = 32 kB
3. Work coordinate system memory capacity for 640 × 480 screen size
1024 pixels × 512 lines = 524,288 bits: 524,288 bits/8 bits/1024 = 64 kB
Bits 15 to 7 of WSAR are reserved. Only 0 should be written to these bits (a read will return an
undefined value).
The WSAH field in WSAR retains its value in a reset.
5 . 4 . 6
DMA Transfer Start Address Registers H and L (DMASRH, DMASRL)
15
Bit:
14
—
—
DMASRH
Initial value:
—
—
Read/Write:
—
—
Bit:
15
14
DMASRL
Initial value:
0
0
Read/Write:
R/W
R/W
DMA transfer start address registers H and L (DMASRH, DMASRL) are 16-bit readable/writable
registers that specify the start address of the transfer destination UGM in a DMA transfer.
148
13
12
11
10
9
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
13
12
11
10
9
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
13
12
11
10
9
DMASL (address A15–A1 setting)
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
8
7
6
5
4
—
—
WSAH (address A22–A16 setting)
—
—
*
*
*
—
—
R/W
R/W
R/W
8
7
6
5
4
—
—
DMASH (address A22–A16 setting)
—
—
0
0
0
—
—
R/W
R/W
R/W
8
7
6
5
4
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
3
2
1
0
*
*
*
*
R/W
R/W
R/W
R/W
3
2
1
0
0
0
0
0
R/W
R/W
R/W
R/W
3
2
1
0
—
0
0
0
—
R/W
R/W
R/W
—
Advertisement
Table of Contents
