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

[Image]

                      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         closed

                                         SW1/switch 8          open

      On-board Video System disabled     SW1/switch 7          open

                                         SW1/switch 8         closed

  »   Factory configured - do not        SW2/switch 1          open
      alter

  »   Factory configured - do not        SW2/switch 2          open
      alter

  »   Monitor type select color          SW2/switch 3          open

      Monitor type select monochrome     SW2/switch 3         closed

  »   Factory configured - do not        SW2/switch 4          open
      alter

                     VIDEO SWITCH CONFIGURATION (SW1)

         Mode           switch     switch    switch    switch    switch 5
                          1          2         3         4

     56Hz vertical       open      open       N/A       N/A        N/A
      refresh 1

     60Hz vertical       open     closed      N/A       N/A        N/A
      refresh 1

     72Hz vertical      closed     open       N/A       N/A        N/A
      refresh 1

  Enable interlaced 2    N/A        N/A       open      open       N/A

  60Hz non-interlaced    N/A        N/A       open     closed      N/A
          2

  72Hz non-interlaced    N/A        N/A      closed     open       N/A
          2

  31.5KHz horizontal     N/A        N/A       N/A       N/A        open
     scan rate 3

   40KHz horizontal      N/A        N/A       N/A       N/A       closed
     scan rate 3

  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