Need help modernizing an old project (CAN bus protocol programming)

I am an individual looking for someone to help modernize a project which was last completed a long time ago (the owner of the project is unavailable for help). The project involves hardware using a CAN bus protocol called IE-Bus communicate with an external computer. The micro controller code this originally called for is completely written, however is outdated, throws many warnings (and some errors on modern C compilers), and is generally a pain to program onto the hardware. It also utilizes the RS-232 standard and, if the micro controller is needed, a USB connection would be needed. In the end, I would like to use a Raspberry Pi using an OEM touchscreen as the interface. The project originally uses a different computer to communicate with and as mentioned uses the RS-232 standard for communication. As far as I understand the Raspberry Pi is ill suited for signal processing and the project calls for use of another micro controller which uses the RS-232 connection to communicate with the computer. If the Raspberry Pi can be used for this without an external signal processor, that would be great, but if one becomes necessary, something easy to program and maintain would be preferable (e.g. Arduino). This folder contains all useful information I could find on the protocol, its programming, a parts list for the original version of this project, some tools for testing, URLs for useful sites, and information regarding similar projects that were completed. [login to view URL] The project is not restricted to the original parameters (i.e. Python can be used in lieu of C). However the Raspberry Pi is necessary as a program written for it will be utilized. Project Requirements: Raspberry Pi Ancillary Requirements (as needed): Arduino (signal processor)