Tandy 1000 Technical Reference Manual

Tandy 1000
828153 IFL Pin Descriptions
Technical Reference Manual
PIN
NUMBER PIN NAME SYMBOL
FUNCTION
1
ADDRESS AEN Indicates
DMA cycle when high,
ENABLE CPU cycle when low.
2-8
ADDRESS A3-A9 These address lines are used for
LINES
decoding the address space
2F8-2FF (secondary) or 3F8-3FF
(primary).
9
SECONDARY IORQ3 Sends interrupts to the CPU while
INTERRUPT
operating in the secondary
REQUEST address
space.
10
GROUND
11
PRIMARY
IORQ4 Sends interrupts to the CPU while
INTERRUPT operating in the primary
REQUEST
address space.
12
PRIMARY OR
ParS An input that determines which
SECONDARY
address space will be used.
UARTS Primary (3F8-3FF) when high or
secondary (2F8-2FF) when low.
13
UART
INT Receives interrupt signal from
INTERRUPT
the 8250.
14
UART CHIP
UCS
Enables the 8250 ACE when low.
SELECT
15
NOT USED
16
NOT USED
17
DATA CHIP
DCS Enables the data bus buffers
SELECT when low.
18
NOT USED
19
NOT USED
20
VCC
Figure 20
83

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