hi

earlier i post a message about 89c51 and i was thinking that the ports of 89c51 behave differently than the 89c2051. but now it looks to me that its not the case. here is what i did.

- i downloaded a simple LED blinking program from net
- its working both on 89c2051 and 89c51.
- then i write my own LED blinking program and make HEX file with SDCC compiler.
- its working fine on 89c2051. but on 89c51, i have no idea what's happening. i use my multimeter and check the port pin. strangely... if i stay in touch with the pin no activity. but when i repeately touching the pin,,, some times there is +5 and some times there is 0 Volts. my first idea is that 89c51 is running the program too fast. i even connect the LCD and 1 out of 30 times LED get initialized meaning it get some signals from processor.

give me any suggestions.

i have a program which runs correctly on 89c2051 but its not working on 89c51 and i'm not in a position to make major changes in that.


Shahzad