Lynx-cards sizes are : 128KB,256KB and 512KB. 1MB is also possible. Lynx sees this cards through a port and may not address them directly, only via a counter, better two counters: one for the block (0..255 on all cards) the other for the position in the current block (0..4095, depends on card-size). The postions wraps, so the block has to be set manualy and the program/game has to know the exact card-size to allow reads of more the one block. Ok here's the pin-out: 1 GND 2 D3 3 D2 4 D4 5 D1 6 D5 7 D0 8 D6 9 D7 10 CARD/ (this is OE/) 11 A1 12 A2 13 A3 14 A6 15 A4 16 A5 17 A0 18 A7 19 A16 20 A17 21 A18 22 A19 23 A15 24 A14 25 A13 26 A12 27 SWCON/ (this is WE/) 28 A8 29 A9 30 A10 31 Vcc 32 AUDIOIN (I/O pin but not analog, digital, for 1MBcards used) 33 Vcc 34 SWVCC Note: A12..A19 is connected to a 74HC164 to select block A0...A10 is connected to a 4040 to select postion A11 is __missing__ CARD/ is strobed on reads SWCON/ is strobed on writes