Hello,

Thanks for your comments; I was out of town; so unable to reply;

As i read one message; that during the design our project increased; 1st we use AT89C51; that time system was small; after development software; features requirement increased; we create it more & more features; start using code banking; instead of thinking to replace the controller etc.

Now the code around 95K +, and getting problems in the system; try with 22.1184 crystal; but all in vain.

Need to rewrite the whole code with readymade RTOS; as our RTOS need more correction; or transplant with Keil RTX51;

Still confuse if we transplant with RTX51, is our system improved his performance; or better to use new controller with Readymade RTOS like Keil.

As when any body write a big amount of code; lot of bug may occurs during the developments; need to fix; so we chose external EP-Rom of 128K, and boot program in micro controller; so any time need to update the software; we can sent the eprom chips as well as sent the "bin" files via e-mail;

and during the whole project; we feel that requirement is around 128K or max 256K size of code; 1K internal SRAM with enough;

All the other IC's i.e. MT8816,MT8888,MT8870,74HCT374,74HCT245,74HCT00,74HCT14,HT1380,DS12C887,MAX232CP, ISD2560,LM324, LM393 etc are operating on 5V, so searching the 5V ARM micro controller;

the ARM Compiler Available with keil; so rest assured for sturdy performance of compiler;

We already seen the demo of Keil 251 compiler; but no RTOS support available from Keil; also the controller are not suitable for our project; if we want to use 128 k external memory; we have to share RD / RW pins;

if we tried for 16bit; investment are more in compiler's and other tools; and after few days if we found the same problem; than we have to think for close the project or we loose from the heart;

And cost are major point to decide; as X2BN are available in 50 cent only; but we can afford more cost for micro controller;

I seen the LPC2101 from Philips; and feel comfortable for present requirement;

any way more comments are welcome.

regards to all.