Hi all,

I think we have fixed the problem. It is the software has claimed to use 1 byte of the on chip ram at address 0x70, and this causes confliction/corruption in the stack pointer when it's growing. I never known printf() is such a complicated function, specially when passing a double argument...

I still wonder why the compiler had passed it, and the old 8031 was OK with it???
Thank you all, this forum is quick and very helpful

Best regard,
Loan Ng.