A hardware/software environment for real-time data acquisition and control

A data acquisition framework based on a RT-Linux host and several embedded processors is presented. A Constant Velocity Mossbauer Spectrometer with controlled temperature sweep is shown as real experimental application. The hardware platform consists of a standard personal computer (PC) supporting several dedicated custom boards. Each board has a microcontroller and additional hardware to interface with the experiment. A simple real-time kernel with a preemptive scheduling scheme was implemented for the microcontroller boards. Tasks are assigned to each stand-alone board during the initialization step. The PC runs the Linux operating system, with its real time extension RT-Linux. The flow of data to and from the boards is implemented with real-time tasks through real-time FIFOs in an event-driven basis. The proposed structure dramatically simplifies the implementation of sophisticated user interfaces, using high level languages like Tcl/Tk or Java, for graphical and remote applications, without degrading real-time performance.