Yup. sorry if you thought i was suggesting that it was 100% compatible, as you point out its not and i was mot trying to imply that. since you are performing surgery on the board, my point is there is a chance you can make it work electrically since in this case the chip is supposed to be software compatible ie since ds1287a are not to be found the 1687 might be able to be pressed into service. On Feb 9, 2013, at 5:58 PM, Jordi Guillaumes i Pons <jg at jordi.guillaumes.name> wrote: El 09/02/2013, a les 23:49, Clem Cole <clemc at ccc.com> va escriure: eeds to check any timing differences and the name of the RW/WR pin is different - but they >>might<< work the same way (might also need to be inverted). In the 1287 that pin is named R/W when the chip uses motorola style timing (MOT connected to Vcc) and WR when it uses intel style (MOT connected to GND). Check the DC1287A datasheet for the gory details. Now the MOT pin is not there in the 1267 (it is used to signal a "wake up" condition), so it doesn't look to be completely compatible with the 1287. Jordi Guillaumes i Pons jg at jordi.guillaumes.name HECnet: BITXOV::JGUILLAUMES