Hi Andrej,

there is one big pitfall on using the Keil C51:

In the "startup.a51" there was only a stack size of one byte reserved.
And if your used data size grows too big, the stack can shrink down to a single byte without any error message.

Please edit the "startup.a51" and change the line
"DS 1" to "DS 16" and then assemble it.

Also reduce the buffer size in your receiver routine e.g. to about 32 bytes and test it again.


Peter