This document is for the full-sized (13.3" x 12.025") 80486DX-25, 80486DX-33 EISA motherboard. The part number for this board is 09-00090-xx. It's identifying features are: an LED between expansion slots #5 and #6; eight 32-bit expansion slots; sixteen sockets for SIMMs (four banks of 4); a socket for a Weitek 4167 coprocessor. The bus speed for this motherboard is fixed at 8MHz. +=============================+ + + + MOTHERBOARD SWITCH SETTINGS + + + + * = Default setting + +=============================+ SW1 --- 1 External cache not invalidated *Off External cache invalidated On 2 On board Bios enabled *Off On board Bios disabled On 3 64K external cache Off 128K or 256K external cache On 4 33MHz system Off 25MHz system On 5 Reserved *Off 6 Reserved *Off 7 CGA / EGA / VGA On Monochrome Off 8 128K external cache On 64K or 256K external cache Off SW2 --- 1 Memory settings (see below) 2 Memory settings (see below) 3 Memory settings (see below) 4 Memory settings (see below) 5 Memory settings (see below) 6 Cache video Bios *Off Don't cache video Bios On 7 Cache D00000-EFFFFF region *On Don't cache D00000-EFFFFF Off 8 Reserved *Off DIP switch settings for memory size =================================== Memory Banks DIP Switch 2 --------------------------------------------------- MB 0 1 2 3 S1 S2 S3 S4 S5 ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 4MB 1MB ON ON ON ON ON 8MB 1MB 1MB OFF ON ON ON ON 12MB 1MB 1MB 1MB ON OFF ON ON ON 16MB 1MB 1MB 1MB 1MB OFF OFF ON ON OFF 16MB 4MB ON ON OFF ON OFF 20MB 1MB 4MB ON ON OFF OFF OFF 24MB 1MB 1MB 4MB ON OFF ON OFF OFF 28MB 1MB 1MB 1MB 4MB OFF ON ON OFF OFF 32MB 4MB 4MB OFF ON OFF ON OFF 36MB 1MB 4MB 4MB ON OFF OFF OFF OFF 40MB 1MB 1MB 4MB 4MB OFF OFF ON OFF OFF 48MB 4MB 4MB 4MB ON OFF OFF ON OFF 52MB 1MB 4MB 4MB 4MB OFF OFF OFF OFF OFF 64MB 4MB 4MB 4MB 4MB OFF OFF OFF ON OFF In the table above, 1MB indicates that four 1Mx9 SIMMs are installed in the bank, and 4MB indicates that four 4Mx9 SIMMs are installed in the bank. The above shows all of the possible memory configurations. When installing more than 16MB of memory, BIOS relocation must be disabled. Bios relocation copies the video Bios (C0000-C7FFF) and the system ROM Bios (F0000-FFFFF) into RAM. The motherboard adds 15MB to these addresses (F00000) to be able to differentiate between the ROM and RAM. Enabling the relocation feature causes the memory above 16MB to become non-contiguous and therefore inaccessible. Micronics Computers has tested and verified the following memory brands: Toshiba, Siemens, Mitsubishi, NEC +=============================+ + + + MOTHERBOARD JUMPER SETTINGS + + + +=============================+ J2 Keyboard connector Pin 1 - Keyboard clock Pin 2 - Keyboard data Pin 3 - no connector Pin 4 - Ground Pin 5 - +5 volts DC J3 External 6-volt battery connector Pin 1 - Battery Positive Pin 2 - no connector Pin 3 - Ground Pin 4 - Ground J15 External speaker Pin 1 - Speaker Pin 2 - no connector Pin 3 - Ground Pin 4 - +5 volts DC J16 Keylock / Power LED Pin 1 - Power LED signal Pin 2 - no connector Pin 3 - Ground Pin 4 - Keyboard lock signal Pin 5 - Ground W3 External cache configuration Pins 1-2 64K or 128K Pins 2-3 256K W4 External cache configuration Pins 1-2 64K Pins 2-3 128K or 256K W5 Reset switch Pin 1 - Signal Pin 2 - Ground W6 Turbo switch Pin 1 - Signal Pin 2 - Ground W7 Turbo LED Pin 1 - Signal Pin 2 - Ground