Colway Solutions
Modbus Member Logo

Making Calls into MSPL-C APIs


Once you have ported the library to your platform, it is time to make calls into its API's. The following table shows a list of API's that may be called by the user's application:



When to call




Periodically for every channel, as soon as some bytes have arrived into the channel.


->   This is the main entry point into the library, also called as the trigger function.

->   This function triggers the stack which checks if data has arrived on the specified channel and processes it.

->   This function must be called after the communication channel's device driver is queried to see if some data has been received in its buffer.


On program start up, once for every communication channel to be opened and initialised.

No (optional)

->   The user is free to perform channel initialisation outside of the library in which case this function need not be implemented and/or called.


Once per channel when Modbus communication is no longer required on that channel.

No (optional)

->   In applications where Modbus communication is expected to be active until the device is switched OFF, this function need not be called at all.

->   As for MSPL_OpenPort, user may choose to implement channel de-initialisation code outside the library in which case this function need not be implemented or called.


When the value of statistical counters maintained by the stack are required.

No (optional)

->   Details of the counters can be found in the function reference section for MSPL_GetMessageCounters()


Back to Index

Privacy Policy Site Map FAQ Contact Us