This document is for the full-sized (13.3" x 12.025") 80486DX-33, 80486DX-50, and 80486DX2-66 EISA motherboard. The part number for this board is 09-00117-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; one proprietary 32-bit slot which accommodates the MVC32LB (a video card based on the ATI Mach 32 chip). The bus speed for this motherboard is fixed at 8MHz. +=============================+ + + + MOTHERBOARD SWITCH SETTINGS + + + + * = Default setting + +=============================+ 1 Memory size (see below) 2 Memory size (see below) 3 Memory size (see below) 4 Memory size (see below) 5 Memory size (see below) 6 Reserved *On 7 Reserved *Off 8 Color video adapter *On Mono video adapter Off DIP switch settings for memory size =================================== Memory Banks DIP Switch 2 --------------------------------------------------- MB 0 1 2 3 S1 S2 S3 S4 S5 ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 1MB 256K ON ON ON ON ON 2MB 256K 256K OFF ON ON ON ON 3MB 256K 256K 256K ON OFF ON ON ON 4MB 256K 256K 256K 256K OFF OFF ON ON ON 4MB 1MB ON ON OFF ON ON 5MB 256K 1MB ON ON OFF OFF ON 6MB 256K 256K 1MB ON OFF ON OFF ON 7MB 256K 256K 256K 1MB OFF ON ON OFF ON 8MB 1MB 1MB OFF ON OFF ON ON 9MB 256K 1MB 1MB ON OFF OFF OFF ON 10MB 256K 256K 1MB 1MB OFF OFF ON OFF ON 12MB 1MB 1MB 1MB ON OFF OFF ON ON 13MB 256K 1MB 1MB 1MB OFF OFF OFF OFF ON 16MB 1MB 1MB 1MB 1MB OFF OFF OFF ON ON 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, 256K indicates that four 256Kx9 SIMMs are installed in the bank, 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 J17 External 6-volt battery connector Pin 1 - Battery Positive Pin 2 - no connector Pin 3 - Ground Pin 4 - Ground J22 External speaker Pin 1 - Speaker Pin 2 - no connector Pin 3 - Ground Pin 4 - +5 volts DC J23 Keylock / Power LED Pin 1 - Power LED signal Pin 2 - no connector Pin 3 - Ground Pin 4 - Keyboard lock signal Pin 5 - Ground 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 W11 Reserved Pins 2-3 W12 Reserved Pins 1-2 W13 Floppy Drive Pins 1-2 -- Enables on-board floppy drive Pins 2-3 -- Disables on-board floppy drive W45 Reserved Pins 1-2 W43 CPU selection Pins 1-2 486DX2-50 Not installed 486DX-33 NOTE: The system board is configured at the factory for either the 486DX-33 or the 486DX2-50. It is not possible to switch the 486DX-33 to the 486DX2-50 (or vice versa) by configuring the jumpers. Serial Port configuration ========================= I/O addresses ------------- COM1 = 3F8-3FFh COM2 = 2F8-2FFh COM1 COM2 W2 W8 W9 ------------------------------------ Enabled Enabled 1-2 1-2 1-2 Enabled Disabled 1-2 1-2 2-3 Disabled Enabled 2-3 1-2 1-2 Disabled Disabled 2-3 1-2 2-3 Parallel Port configuration =========================== Port I/O address W3 W4 W10 --------------------------------------- LPT1 3BC-3BEh 1-2 2-3 2-3 LPT2 378-37Ah 1-2 1-2 2-3 LPT3 278-27Ah 2-3 1-2 2-3 Disabled 2-3 2-3 2-3 Cache configuration =================== Cache W20 W21 W41 W44 ---------------------------- 64K N/C N/C N/C 2-3 256K 1-2 1-2 1-2 1-2 N/C = Not Connected