Here are the pins for the Philips 87c751 (2K EPROM, 64 RAM, I2C, FXTAL=12MHz): 1 - P3.4/A4 2 - P3.3/A3 3 - P3.2/A2/A10 4 - P3.1/A1/A9 5 - P3.0/A0/A8 6 - P0.2/VPP 7 - P0.1/SDA/OE-PGM 8 - P0.0/SCL/ASEL 9 - RST 10 - XTAL2 11 - XTAL1 12 - VSS 13 - P1.0/D0 14 - P1.1/D1 15 - P1.2/D2 16 - P1.3/D3 17 - P1.4/D4 18 - P1.5/ -INT0 /D5 19 - P1.6/ -INT1 /D6 20 - P1.7/T0/D7 21 - P3.7/A7 22 - P3.6/A6 23 - P3.5/A5 24 - VCC For the 87C750 (1K EPROM, 64 RAM, FXTAL=12MHz) only the following pins are different: 7 - P0.1/OE-PGM 8 - P0.0/ASEL Best regards, Pavel Haiduc, DHP Technology Romania