tailieunhanh - The VHDL Cookbook phần 5

Phần khai báo tờ khai cấu hình cho phép cấu hình để sử dụng các mục từ các thư viện và các gói. Cấu hình khối ngoài cùng trong việc khai báo cấu hình xác định cấu hình cho một kiến trúc của thực thể được đặt tên. Ví dụ, trong Chương 3, chúng tôi đã có một ví dụ về một thực thể xử lý và kiến trúc, đã phác thảo một lần nữa trong | 5. Model Organisation 5-3 entity processor is generic max_clock_speed frequency 30 MHz port port list end processor architecture block_structure of processor is declarations begin control_unit block port port list port map association list declarations for control_unit begin statements for control_unit end block control_unit data_path block port port list port map association list declarations for data_path begin statements for data_path end block data_path end block_structure Figure 5-1. Example processor entity and architecture body. port_map_aspect port map port_association_list The declarative part of the configuration declaration allows the configuration to use items from libraries and packages. The outermost block configuration in the configuration declaration defines the configuration for an architecture of the named entity. For example in Chapter 3 we had an example of a processor entity and architecture outlined again in Figure5-1. The overall structure of a configuration declaration for this architecture might be configuration test_config of processor is use work. for block_structure configuration items end for end test_config In this example the contents of a package called processor_types in the current working library are made visible and the block configuration refers to the architecture block_structure of the entity processor. Within the block configuration for the architecture the submodules of the architecture may be configured. These submodules include blocks and component instances. A block is configured with a nested block configuration. For example the blocks in the above architecture can be configured as shown in Figure5-2. Where a submodule is an instance of a component a component configuration is used to bind an entity to the component instance. To illustrate suppose the data_path block in the above example contained an 5-4 The VHDL Cookbook configuration test_config of processor is use work. for .