TANDY/RADIO SHACK

MFP/420s

Processor

80486SX/80487SX

Processor Speed

20MHz

Chip Set

Tandy

Max. Onboard DRAM

32MB

Cache

None

BIOS

Phoenix/Grid

Dimensions

355mm x 304mm

I/O Options

Bus mouse port, floppy drive interface, IDE interface

parallel port, serial port (2), VGA feature connector, VGA port

NPU Options

4167

VRAM CONFIGURATION

Size

VRAM

Location

SW1/switch 6

512KB

(2) 44256

Bank 0

closed

1024KB

(2) 44256

Banks 0 & 1

open

CONNECTIONS

Purpose

Location

Purpose

Location

External battery

BAT

Floppy drive interface

C6

Board LED

BLED

IDE interface

C7

VGA port

C1

Power LED

PLED

Bus mouse port

C2

Reset switch

RES

Parallel port

C3

Speaker

SPK

Serial port 2

C4

Riser card

S1

Serial port 1

C5

   

USER CONFIGURABLE SETTINGS

Function

Switch

Position

»

On-board Video System enabled

SW1/switch 7

SW1/switch 8

closed

open

 

On-board Video System disabled

SW1/switch 7

SW1/switch 8

open

closed

»

Factory configured - do not alter

SW2/switch 1

open

»

Factory configured - do not alter

SW2/switch 2

open

»

Monitor type select color

SW2/switch 3

open

 

Monitor type select monochrome

SW2/switch 3

closed

»

Factory configured - do not alter

SW2/switch 4

open

VIDEO SWITCH CONFIGURATION (SW1)

Mode

switch 1

switch 2

switch 3

switch 4

switch 5

56Hz vertical refresh 1

open

open

N/A

N/A

N/A

60Hz vertical refresh 1

open

closed

N/A

N/A

N/A

72Hz vertical refresh 1

closed

open

N/A

N/A

N/A

Enable interlaced 2

N/A

N/A

open

open

N/A

60Hz non-interlaced 2

N/A

N/A

open

closed

N/A

72Hz non-interlaced 2

N/A

N/A

closed

open

N/A

31.5KHz horizontal scan rate 3

N/A

N/A

N/A

N/A

open

40KHz horizontal scan rate 3

N/A

N/A

N/A

N/A

closed

Note 1 :When monitor resolution is 800 x 600.

Note 2 :When monitor resolution is 1024 x 768.

Note 3 :When monitor resolution is 640 x 480 or below.

DRAM CONFIGURATION

Size

Bank 0

Bank 1

4MB

(4) 1M x 9

NONE

5MB

(4) 1M x 9

(4) 256K x 9

8MB

(4) 1M x 9

(4) 1M x 9

16MB

(4) 4M x 9

NONE

17MB

(4) 256K x 9

(4) 4M x 9

20MB

(4) 1M x 9

(4) 4M x 9

32MB

(4) 4M x 9

(4) 4M x 9