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Hardware Functional Specification S1D13505
Issue Date: 01/02/02 X23A-A-001-14
12 Ink/Cursor Architecture

12.1 Ink/Cursor Buffers

The Ink/Cursor buffers contain formatted image data for the Ink Layer or Hardware Cursor. There

may be several Ink/Cursor images stored in the display buffer but only one may be active at any

given time.

The active Ink/Cursor buffer is selected by the Ink/Cursor Start Address register (REG[30h]). This

register defines the start address for the active Ink/Cursor buffer. The Ink/Cursor buffer must be

positioned where it does not conflict with the image buffer and half-frame buffer. The start address

for the Ink/Cursor buffer is programmed as shown in the following table:

The Ink/Cursor image is stored contiguously. The address offset from the starting word of line n to

the starting word of line n+1 is calculated as follows:

Ink Address Offset (words) = REG[04h] + 1
Cursor Address Offset (words) = 8

12.2 Ink/Cursor Data Format

The Ink/Cursor image is always 2 bit-per-pixel. The following diagram shows the Ink/Cursor data

format for a little-endian system.

Figure 12-1: Ink/Cursor Data Format
Table 12-1: Ink/Cursor Start Address Encoding
Ink/Cursor Start
Address Bits [7:0] Start Address (Bytes) Comments
0 Display Buffer Size - 1024 This default value is suitable for a cursor
when there is no half-frame buffer.
n = 255...1 Display Buffer Size -
(n × 8192)
These positions can be used to:
position an Ink buffer at the top of the
display buffer;
position an Ink buffer between the image
and half-frame buffers;
position a Cursor buffer between the image
and half-frame buffers;
select from a multiple of Cursor buffers.
2 bpp:
A0B0A1B1A2B2A3B3
Host Address Ink/Cursor Buffer
A4B4A5B5A6B6A7B7
bit 7 bit 0
Byte 0
Byte 1
Panel Display
P0P1P2P3P4P5P6P7
Pn = (An, Bn)