Hi Michael,

1) Yes I am doing this by bit bang. The module I am using is an Atmel AT24C1024B. It can run at 400kHz or 1Mhz depending on what voltage you apply, because I am using ~3.3V it should run at 1Mhz.

2) The 8052 that I am using is an Atmel AT89C8131A-M running at 12MHz. I think is powerfull enough for my little OS, which is not so complex afterall. On one task is checking the internal USB stak, and in the second task is doing user-application business logic. In fact everything started from Atmel's sample application that is posted on their product webpage.

3) The on-board I2C periphal or TWI how it is called by Atmel it is faster indeed, but it knows only 8bit addressing which is quite a limitation. Serial EEPROM is deprecated, but is too late now, at that moment my choice was motivated by the fact that I had programmed once upon a time during college and it was somehow easier for me to start with. What is stupid with the serial EEPROM is the 5ms delay after you write something, has no sense to push the memory to 1MHz since you have this 5ms limitation. Your 25-28ms is realistic enough.

4) The sensor is not I2C, it is something proprietary.

5) Sounds a good idea, is a good solution to measure really how much it takes for read date from the sensor and how mouch it takes to write into memory.

6) It is correct what you are saying but I really don't think that this is my case. I already checked this aspects.

Sandu