Figure 1: Software Structure of the SiVMEXI package
VMEtaxi modules are based on the AMD taxi chip set for fibre-optic communication and data-transfer purposes between VMEbus crates [2]. Intelligent control functionality is catered for by on-board 68020/030 microprocessors with the 68030 Mark-2 series offering additional enhanced performance by double-links and local, on-board, extension static memory of up to 2 MBytes [3].
The original software package was developed for the general-purpose operation of such VMEtaxi modules, providing several layers of communication protocol including an in-built multi-adaptable data acquisition structure for large VMEbus-based systems [4]. In particular it provided the central coordinating core for the data acquisition system of the H1 particle physics experiment [5]. During 1992 and 1993 proposals were approved for the inclusion of Silicon Tracker detector elements to be added to this experiment [6,7]. For this custom-built front end electronics was designed [8] via VMEbus readout controllers [9]. It is the purpose of the SiVMEXI software extension to provide a coherent core framework for managing such readout scenarios. The software structure has been organised to remain as optimised and coherent with the original package as possible, providing a modular layered approach which could be adapted to other configurations and environments fairly comfortably (Figure 1). In addition, as with the VMEXI_SSP, external processor control is catered for and several applications have been written to take advantage of this higher-level of VMEbus communication protocol [10,11].
Figure 1: Software Structure of the SiVMEXI package