How to use this driver:
Running tests:
- Install ruby. You can obtain ruby from https://www.ruby-lang.org
- Install ceedling. From your command prompt run:
gem install ceedling
- Navigate to this_library_sources/Test directory
- Press Shift+RMB and select "Open command prompt" from context menu
- To launch the test sequence type:
rake test:all
- All tests should be passed
Adding library to your project
- Add this_library_sources/Include directory to include path in your IDE or makefile
- Add files from this_library_sources/Source directory to sources path or just copy it into your Source folder
- Use modbus_user_data.template.h and proto_bindings.template.h to implement your own modbus_user_data.h and proto_bindings.h, placed in you project Include folder.
Binding to low level drivers:
- You should implement two drivers with appropriate API. The first is Receiver/Transmitter (usually UART) The second is hardware timer which will run in one-shot mode. Software/Virtual timers can also be used.
- See the timer_driver.template.h and uart_driver.template.h to understand what API do you need.
- Write appropriate functions to your proto_bindings.h file.
Implementing in the Application:
- Define an entity of proto_t and modbus_user_data_t.
- Define and initialize an entity of proto_init_t.
- Assign actual data addresses to the pointers, defined in modbus_user_data_t. Keep in mind that modbus registers are 16-bit wide.
- Set WE field on those registers that should be write accessible.
- Initialize protocol state using protoInit().
- Place protoBackgroundProcess() to your main loop or call it periodically
- See an example in example folder.
warning Only 2 Modbus functions are currently implemented: READ HOLDING REGISTERS and WRITE SINGLE REGISTER,
which is enough in most situations.
warning Only static address are used in this version (Reading and assigning device address at initialization stage)