--- Quote Start ---
At the Rx file ser_in as input port ,
At the Rx file i declare data_in as signal and connect : Data_in=> Data_in_D .
There are 11 errors at Rx file after compiling .
one of the errors is :
1. ** Error: D:/Final Project/Technical/Top/hdl/Rx.vhd(34): (vcom-1136) Unknown identifier "Data_in_D".
Data_in_D is the input port to MetaFix - declared at Rx file . i tried to declare it as a signal at Rx file but still it has the same error .
--- Quote End ---
No it is not declared in rx_vhd. It is port to submodule(Metfix). Thus it is unknown at rx_vhd.
Just make a search for every errored signal and see if it is declared.