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 a 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 standalone 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