Check syntax and simulation in the ISE 10.1 environment. The error "this signal is connected to multiple drivers ."

Background: Xilinx FPGA, ise 10.1 development environment, and OpenGL

Problem description: The check syntax is correct. You can use Modelsim for simulation, but an error occurs in combination. The error is as follows:

 

Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <56>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <48>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <40>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <32>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <24>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <16>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <10>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_toslv> on signal <measureframe <0>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_tofwd> on signal <measureframe <40>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_tofwd> on signal <measureframe <32>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_tofwd> on signal <measureframe <24>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_tofwd> on signal <measureframe <16>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_tofwd> on signal <measureframe <10>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_tofwd> on signal <measureframe <0>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_topc> on signal <measureframe <40>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_topc> on signal <measureframe <32>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_topc> on signal <measureframe <24>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_topc> on signal <measureframe <16>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_topc> on signal <measureframe <10>; this signal is connected to multiple drivers.
Error: XST: 528-multi-source in Unit <mst_process_format_topc> on signal <measureframe <0>; this signal is connected to multiple drivers.

 

Such errors assign values to the same Reg variable in multiple always blocks. Such programs cannot be integrated and therefore must be modified.

 

Remember, you can only modify the value of the same reg-type variable in one always block. Of course, you can reference the value in other blocks!

 

In fact, this kind of error is understandable. Imagine that both always work under the clock drive. If, I say, if, at the same clock time, in the two alway blocks, the assignment conditions for the same Reg type are met. So what do you want FPGA to do? Who should let it listen to? Which always?

In the end, the circuit is generated in FPGA. What makes FPGA feel like? How to generate a circuit?