HI FRIENDS,

I am using P89c669 as micro-controller. I am facing a problem regarding IAP routines.

The problem is that I am not able to program a BLOCK of data in continuous locations of flash memory.(it is writting any single byte correctly)

e.g.
1) if I write bytes from 0xE000 to 0xE400, then only locations 0xE000, 0xE100 ... 0xE400 (i.e. lower addr = 00) are programmed correctly. other values returned are garbage.

2) if I program byte at location 0xE000, 0xE001 & 0xE100 only then value at 0xE001 is not written correctly.(0xE000 & 0xE100 are programmed correctly).

3) if I program 0xE001 alone then it is programmed correctly.

can anyone suggest me why is this happening?
is there any restriction of 256 bytes.

and how to overcome this situation?