ABIT COMPUTER CORPORATION AH4/AH4T (REV. 1.2) Processor 80486SX/SL80486SX/CX486M7/80486DX/SL80486DX/CX486DX2/AM486DX2/80486DX2/SL80486DX2/AM486DX4/80486DX4 Processor 20/25/33/40/50(internal)/66(internal)/75(internal)/100(internal)MHz Speed Chip Set Unidentifed Max. 128MB Onboard DRAM Cache 128/256/512KB BIOS Award Dimensions 330mm x 218mm I/O 32-bit VESA local bus slots (3), green PC connector Options NPU None Options [Image] CONNECTIONS Purpose Location Purpose Location External battery J1 Reset switch JW3 Green PC connector JP45 pins 7 - Turbo LED JW4 8 Power LED & keylock JW1 Turbo switch JW5 Speaker JW2 32-bit VESA local SL1 - SL3 bus slots USER CONFIGURABLE SETTINGS Function Jumper Position » CMOS memory normal operation JP16 pins 1 & 2 closed CMOS memory clear JP16 pins 2 & 3 closed » Factory configured - do not alter JP17 N/A » Factory configured - do not alter JP19 pins 1 & 2 closed » Factory configured - do not alter JP23 pins 1 & 2 closed » Factory configured - do not alter JP26 Open » Factory configured - do not alter JP30 N/A » Factory configured - do not alter JP31 N/A » Factory configured - do not alter JP42 Closed Note: The locations of JP19, JP23 & JP42 are unidentified. DRAM CONFIGURATION Size Bank 0 Bank 1 Bank 2 Bank 3 1MB (1) 256K x NONE NONE NONE 36 2MB (1) 256K x (1) 256K x NONE NONE 36 36 2MB (1) 512K x NONE NONE NONE 36 4MB (1) 512K x (1) 512K x NONE NONE 36 36 4MB (1) 1M x 36 NONE NONE NONE 4MB (1) 256K x (1) 256K x (1) 512K x NONE 36 36 36 5MB (1) 256K x (1) 1M x 36 NONE NONE 36 6MB (1) 256K x (1) 256K x (1) 1M x 36 NONE 36 36 6MB (1) 512K x (1) 1M x 36 NONE NONE 36 8MB (1) 256K x (1) 256K x (1) 512K x (1) 1M x 36 36 36 36 8MB (1) 512K x (1) 512K x (1) 1M x 36 NONE 36 36 8MB (1) 1M x 36 (1) 1M x 36 NONE NONE 8MB (1) 2M x 36 NONE NONE NONE 10MB (1) 256K x (1) 256K x (1) 1M x 36 (1) 1M x 36 36 36 12MB (1) 512K x (1) 512K x (1) 1M x 36 (1) 1M x 36 36 36 12MB (1) 1M x 36 (1) 1M x 36 (1) 1M x 36 NONE 16MB (1) 2M x 36 (1) 2M x 36 NONE NONE 16MB (1) 1M x 36 (1) 1M x 36 (1) 1M x 36 (1) 1M x 36 16MB (1) 4M x 36 NONE NONE NONE 17MB (1) 256K x (1) 4M x 36 NONE NONE 36 18MB (1) 256K x (1) 256K x (1) 4M x 36 NONE 36 36 20MB (1) 512K x (1) 512K x (1) 4M x 36 NONE 36 36 20MB (1) 1M x 36 (1) 4M x 36 NONE NONE 24MB (1) 2M x 36 (1) 2M x 36 (1) 2M x 36 NONE 24MB (1) 512K x (1) 512K x (1) 1M x 36 (1) 4M x 36 36 36 24MB (1) 1M x 36 (1) 1M x 36 (1) 4M x 36 NONE 32MB (1) 2M x 36 (1) 2M x 36 (1) 2M x 36 (1) 2M x 36 32MB (1) 4M x 36 (1) 4M x 36 NONE NONE 32MB (1) 8M x 36 NONE NONE NONE 36MB (1) 512K x (1) 512K x (1) 4M x 36 (1) 4M x 36 36 36 36MB (1) 1M x 36 (1) 4M x 36 (1) 4M x 36 NONE DRAM CONFIGURATION (CON’T) Size Bank 0 Bank 1 Bank 2 Bank 3 36MB (1) 1M x 36 (1) 8M x 36 NONE NONE 40MB (1) 1M x 36 (1) 1M x 36 (1) 4M x 36 (1) 4M x 36 40MB (1) 1M x 36 (1) 1M x 36 (1) 8M x 36 NONE 48MB (1) 4M x 36 (1) 4M x 36 (1) 4M x 36 NONE 48MB (1) 4M x 36 (1) 8M x 36 NONE NONE 64MB (1) 4M x 36 (1) 4M x 36 (1) 4M x 36 (1) 4M x 36 64MB (1) 16M x 36 NONE NONE NONE 64MB (1) 4M x 36 (1) 4M x 36 (1) 8M x 36 NONE 64MB (1) 8M x 36 (1) 8M x 36 NONE NONE 65MB (1) 256K x 36 (1) 16M x 36 NONE NONE 68MB (1) 1M x 36 (1) 16M x 36 NONE NONE 68MB (1) 1M x 36 (1) 8M x 36 (1) 8M x 36 NONE 72MB (1) 1M x 36 (1) 1M x 36 (1) 16M x 36 NONE 72MB (1) 1M x 36 (1) 1M x 36 (1) 8M x 36 (1) 8M x 36 80MB (1) 4M x 36 (1) 16M x 36 NONE NONE 80MB (1) 4M x 36 (1) 8M x 36 (1) 8M x 36 NONE 96MB (1) 4M x 36 (1) 4M x 36 (1) 16M x 36 NONE 96MB (1) 4M x 36 (1) 4M x 36 (1) 8M x 36 (1) 8M x 36 96MB (1) 8M x 36 (1) 8M x 36 (1) 8M x 36 NONE 128MB (1) 16M x 36 (1) 16M x 36 NONE NONE 128MB (1) 8M x 36 (1) 8M x 36 (1) 8M x 36 (1) 8M x 36 CACHE CONFIGURATION Size Bank 0 Bank 1 TAG 128KB (4) 32K x 8 NONE (1) 8K x 8 256KB (4) 32K x 8 (4) 32K x 8 (1) 32K x 8 256KB (4) 64K x 8 NONE (1) 32K x 8 512KB (4) 64K x 8 (4) 64K x 8 (1) 32K x 8 512KB (4) 128K x 8 NONE (1) 32K x 8 CACHE JUMPER CONFIGURATION Size JP1 JP2 JP4 JP40 JP41 128KB 1 & 2 1 & 2 1 & 2 1 & 2 1 & 2 256KB 2 & 3 2 & 3 1 & 2 2 & 3 2 & 3 256KB 1 & 2 2 & 3 1 & 2 1 & 2 1 & 2 512KB 2 & 3 2 & 3 2 & 3 2 & 3 2 & 3 512KB 1 & 2 2 & 3 2 & 3 1 & 2 1 & 2 Note: Pins designated should be in the closed position. CPU TYPE CONFIGURATION Type JP8 JP9 JP11 JP12 JP14 80486SX 2 & 3 Open Open 3 & 4 2 & 3 SL80486SX 2 & 3 Open Open 3 & 4 2 & 3 CX486M7 1 & 2 Closed 2 & 3 2 & 3 1 & 2, 3 & 4 80486DX 1 & 2 Closed 2 & 3 3 & 4 2 & 3 SL80486DX 1 & 2 Closed 2 & 3 3 & 4 2 & 3 CX486DX2 1 & 2 Closed 2 & 3 2 & 3 1 & 2, 3 & 4 AM486DX2 1 & 2 Closed 2 & 3 3 & 4 2 & 3 80486DX2 1 & 2 Closed 2 & 3 3 & 4 2 & 3 SL80486DX2 1 & 2 Closed 2 & 3 3 & 4 2 & 3 AM486DX4 1 & 2 Closed 2 & 3 3 & 4 2 & 3 80486DX4 1 & 2 Closed 2 & 3 3 & 4 2 & 3 Note: Pins designated should be in the closed position. SL80486DX/DX2 is only available on the AH4T mainboard CPU TYPE CONFIGURATION Type JP15 JP21 JP22 JP24 JP25 80486SX 4 & 5 2 & 3 1 & 2 Open Open SL80486SX 4 & 5 2 & 3 1 & 2 Open Open CX486M7 2 & 3 1 & 2 2 & 3 2 & 3 2 & 3 80486DX 4 & 5 2 & 3 1 & 2 Open Open SL80486DX 4 & 5 2 & 3 1 & 2 Open Open CX486DX2 2 & 3 1 & 2 2 & 3 2 & 3 2 & 3 AM486DX2 4 & 5 2 & 3 1 & 2 Open Open 80486DX2 4 & 5 2 & 3 1 & 2 Open Open SL80486DX2 4 & 5 2 & 3 1 & 2 Open Open AM486DX4 4 & 5 2 & 3 1 & 2 Open Open 80486DX4 4 & 5 2 & 3 1 & 2 Open Open Note: Pins designated should be in the closed position. SL80486DX/DX2 is only available on the AH4T mainboard CPU TYPE CONFIGURATION Type JP32 JP46 JP48 JP49 JP50 JP62 80486SX 1 & 2 2 & 3 2 & 3 Open 2 & 3 Open SL80486SX 1 & 2 2 & 3 2 & 3 Open 2 & 3 Open CX486M7 1 & 2 1 & 2 2 & 3 Open 2 & 3 Open 80486DX 1 & 2 2 & 3 2 & 3 Open 2 & 3 Open SL80486DX 1 & 2 2 & 3 2 & 3 Open 2 & 3 Open CX486DX2 1 & 2 1 & 2 1 & 2 Open 1 & 2 Open AM486DX2 1 & 2 2 & 3 1 & 2 Open 1 & 2 Open 80486DX2 1 & 2 2 & 3 2 & 3 Open 2 & 3 Open SL80486DX2 1 & 2 2 & 3 2 & 3 Open 2 & 3 Open AM486DX4 1 & 2 2 & 3 1 & 2 1 & 2 1 & 2 Closed 80486DX4 Open 2 & 3 1 & 2 1 & 2 1 & 2 Open Note: Pins designated should be in the closed position. SL80486DX/DX2 is only available on the AH4T mainboard CPU SPEED CONFIGURATION Speed JP5 JP6 JP7 20MHz Closed Open Closed 25MHz Closed Closed Open 33MHz Open Closed Closed 40MHz Closed Open Open 50iMHz Closed Closed Open 66iMHz Open Closed Closed 75iMHz Closed Closed Open 100iMHz Open Closed Closed CPU VOLTAGE CONFIGURATION Voltage JP53 JP54 JP55 JP56 3.3v Closed Open Open Open 3.45v Open Closed Open Open 3.6v Open Open Closed Open 4v Open Open Open Closed BUS SPEED CONFIGURATION CPU speed JP29 <= 33MHz pins 1 & 2 closed > 33MHz pins 2 & 3 closed