Astrocade 256K Maxflash Memory Map ---------------------------------- Revision 1.1 By Adam Trionfo About the Maxflash Cartridge: The Maxflash cart resides in the Astrocade's 8K cartridge area from $2000-$3FFF. The highest bank (Bank 63) is ALWAYS mapped to the lowest 4K ($2000-$2FFF). The remaining banks can be switched in and out of the Astrocade's high 4K cartridge area from $3000-$3FFF. A bankswitch occurs when a read takes place in one of 64 memory locations in the cartridge area from $3Fc0-$3FFF. For instance, if the area $3FC0 is read, then Bank 0 (located on the cartridge from $00000-$00FFF) is seen by the Astrocade as the high 4K of of the cartridge area ($3000-$3FFF). An Astrocade program that takes care of the bankswitching must ALWAYS start at $2000, which is Bank 63. In fact, any 2K or 4K normal cartridge can reside in Bank 63 and it will act as normal. The Memory Map: Bank Selected 256K Cart Memory Astrocade Memory Map ------------- ----------------- ----------------------------------- 0 $00000-$00FFF $3000-$3FFF - ($3FC0 + $00) = $3FC0 1 $01000-$01FFF $3000-$3FFF - ($3FC0 + $01) = $3FC1 2 $02000-$02FFF $3000-$3FFF - ($3FC0 + $02) = $3FC2 3 $03000-$03FFF $3000-$3FFF - ($3FC0 + $03) = $3FC3 4 $04000-$04FFF $3000-$3FFF - ($3FC0 + $04) = $3FC4 5 $05000-$05FFF $3000-$3FFF - ($3FC0 + $05) = $3FC5 6 $06000-$06FFF $3000-$3FFF - ($3FC0 + $06) = $3FC6 7 $07000-$07FFF $3000-$3FFF - ($3FC0 + $07) = $3FC7 8 $08000-$08FFF $3000-$3FFF - ($3FC0 + $08) = $3FC8 9 $09000-$09FFF $3000-$3FFF - ($3FC0 + $09) = $3FC9 10 $0A000-$0AFFF $3000-$3FFF - ($3FC0 + $0A) = $3FCA 11 $0B000-$0BFFF $3000-$3FFF - ($3FC0 + $0B) = $3FCB 12 $0C000-$0CFFF $3000-$3FFF - ($3FC0 + $0C) = $3FCC 13 $0D000-$0DFFF $3000-$3FFF - ($3FC0 + $0D) = $3FCD 14 $0E000-$0EFFF $3000-$3FFF - ($3FC0 + $OE) = $3FCE 15 $0F000-$0FFFF $3000-$3FFF - ($3FC0 + $OF) = $3FCF 16 $10000-$10FFF $3000-$3FFF - ($3FC0 + $10) = $3FD0 17 $11000-$11FFF $3000-$3FFF - ($3FC0 + $11) = $3FD1 18 $12000-$12FFF $3000-$3FFF - ($3FC0 + $12) = $3FD2 19 $13000-$13FFF $3000-$3FFF - ($3FC0 + $13) = $3FD3 20 $14000-$14FFF $3000-$3FFF - ($3FC0 + $14) = $3FD4 21 $15000-$15FFF $3000-$3FFF - ($3FC0 + $15) = $3FD5 22 $16000-$16FFF $3000-$3FFF - ($3FC0 + $16) = $3FD6 23 $17000-$17FFF $3000-$3FFF - ($3FC0 + $17) = $3FD7 24 $18000-$18FFF $3000-$3FFF - ($3FC0 + $18) = $3FD8 25 $19000-$19FFF $3000-$3FFF - ($3FC0 + $19) = $3FD9 26 $1A000-$1AFFF $3000-$3FFF - ($3FC0 + $1A) = $3FDA 27 $1B000-$1BFFF $3000-$3FFF - ($3FC0 + $1B) = $3FDB 28 $1C000-$1CFFF $3000-$3FFF - ($3FC0 + $1C) = $3FDC 29 $1D000-$1DFFF $3000-$3FFF - ($3FC0 + $1D) = $3FDD 30 $1E000-$1EFFF $3000-$3FFF - ($3FC0 + $1E) = $3FDE 31 $1F000-$1FFFF $3000-$3FFF - ($3FC0 + $1F) = $3FDF 32 $20000-$20FFF $3000-$3FFF - ($3FC0 + $20) = $3FE0 33 $21000-$21FFF $3000-$3FFF - ($3FC0 + $21) = $3FE1 34 $22000-$22FFF $3000-$3FFF - ($3FC0 + $22) = $3FE2 35 $23000-$23FFF $3000-$3FFF - ($3FC0 + $23) = $3FE3 36 $24000-$24FFF $3000-$3FFF - ($3FC0 + $24) = $3FE4 37 $25000-$25FFF $3000-$3FFF - ($3FC0 + $25) = $3FE5 38 $26000-$26FFF $3000-$3FFF - ($3FC0 + $26) = $3FE6 39 $27000-$27FFF $3000-$3FFF - ($3FC0 + $27) = $3FE7 40 $28000-$28FFF $3000-$3FFF - ($3FC0 + $28) = $3FE8 41 $29000-$29FFF $3000-$3FFF - ($3FC0 + $29) = $3FE9 42 $2A000-$2AFFF $3000-$3FFF - ($3FC0 + $2A) = $3FEA 43 $2B000-$2BFFF $3000-$3FFF - ($3FC0 + $2B) = $3FEB 44 $2C000-$2CFFF $3000-$3FFF - ($3FC0 + $2C) = $3FEC 45 $2D000-$2DFFF $3000-$3FFF - ($3FC0 + $2D) = $3FED 46 $2E000-$2EFFF $3000-$3FFF - ($3FC0 + $2E) = $3FEE 47 $2F000-$2FFFF $3000-$3FFF - ($3FC0 + $2F) = $3FEF 48 $30000-$30FFF $3000-$3FFF - ($3FC0 + $30) = $3FF0 49 $31000-$31FFF $3000-$3FFF - ($3FC0 + $31) = $3FF1 50 $32000-$32FFF $3000-$3FFF - ($3FC0 + $32) = $3FF2 51 $33000-$33FFF $3000-$3FFF - ($3FC0 + $33) = $3FF3 52 $34000-$34FFF $3000-$3FFF - ($3FC0 + $34) = $3FF4 53 $35000-$35FFF $3000-$3FFF - ($3FC0 + $35) = $3FF5 54 $36000-$36FFF $3000-$3FFF - ($3FC0 + $36) = $3FF6 55 $37000-$37FFF $3000-$3FFF - ($3FC0 + $37) = $3FF7 56 $38000-$38FFF $3000-$3FFF - ($3FC0 + $38) = $3FF8 57 $39000-$39FFF $3000-$3FFF - ($3FC0 + $39) = $3FF9 58 $3A000-$3AFFF $3000-$3FFF - ($3FC0 + $3A) = $3FFA 59 $3B000-$3BFFF $3000-$3FFF - ($3FC0 + $3B) = $3FFB 60 $3C000-$3CFFF $3000-$3FFF - ($3FC0 + $3C) = $3FFC 61 $3D000-$3DFFF $3000-$3FFF - ($3FC0 + $3D) = $3FFD 62 $3E000-$3EFFF $3000-$3FFF - ($3FC0 + $3E) = $3FFE 63 $3F000-$3FFFF $3000-$3FFF - ($3FC0 + $3F) = $3FFF Remember that Bank 63 also ALWAYS has this attribute: 63 $3F000-$3FFFF $2000-$2FFF - Start of Cartridge Area Revision History: ----------------- Revision 1.1 (September 1, 2011), Updated by Adam Trionfo - Added additional information about how bankswitching works Revision 1.0 (August 31, 20 11), Created by Adam Trionfo - First Release