Tandy 1000 Technical Reference Manual

Tandy 1000
Technical Reference Manual
The following is a table of the graphics storage organization for two banks of
8000 bytes:
Even Scans
(0, 2, 4, ... 196)
Odd Scans (1, 3, 5, ... 199)
f.- 80 Bytes -l Memory Address
B
OOOOH
1F3FH
2000H
3F3FH
Graphics Storage Organization
High-resolution 2-Color Graphics
The high-resolution 2-color mode may require a high-resolution monitor for cor-
rect operation. This
mode can display 2 of 16 possible colors. It contains 200
rows of 640 pixels, requires 16K bytes of read/write memory, and formats 8
pixels per byte. This
mode is available in the IBM PC and IBM PCjr.
Byte 0
= eighth pixel
Byte 1
= seventh pixel
Byte 2
= sixth pixel
Byte 3
= fifth pixel
Byte 4
= fourth pixel
Byte
5 = third pixel
Byte 6
= second pixel
Byte
7 = first pixel
High-Resolution 4-Color Graphics
Odd Bytes
PA1 (7)
PA1 (6)
PA1 (5)
PA1 (4)
PA1 (3)
PA 1 (2)
PA1 (2)
PA1 (0)
First Display Pixel
Second Display Pixel
Third Display Pixel
Fourth Display Pixel
Fifth Display Pixel
Sixth Display Pixel
Seventh Display Pixel
Eighth Display Pixel
The high-resolution 4-color mode
may require a high-resolution monitor for cor-
rect operation. This
mode can display 4 out of 16 colors. (Each pixel selects
1 of 4 colors.)
It contains 200 rows of 640 pixels, requires 32K bytes of read/write
memory and formats 8 pixels per two bytes
(1 even-byte and 1 odd-byte). This
mode is only supported on the IBM PCjr.
Even Bytes
PAO (7)
PAO (6)
PAO (5)
PAO (4)
PAO (4)
PAO (3)
PAO (1)
PAO (0)
48

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200