Environmental pollution, especially water pollution, is one of the most serious problems faced by environmental engineers and scientists. Hence it is of utmost importance to build a system which can measure the concentration of various pollutants in water. These pollutants can be inorganic chemicals such as nitrates, chlorides, sulphates, phosphates etc. One of the foremost requirement of such a system is that user should be able to control it from base locations. These are called in situ environmental monitoring systems. The system essentially has a set of sensors to detect the concentration of pollutants in water and it should also have a signal processing interface which can digitize the outputs of these sensors (analog output) and send it to a user through a wireless communication link. User, at the base location, should be able to back annotate the received bits to check the actual pollution level. The signal processing interface should be reconfigurable in addition of other features so that user can program the interface according to their requirements. A research group under the supervision of Dr Papautsky at University of Cincinnati has developed microelectrode sensor array. The signal processing interface is a mixed signal interface with analog to digital converter and a control logic block with a set of reconfigurable registers. The control logic block is designed using standard cell based methodology. Such a mixed signal ASIC is designed and fabricated through MOSIS using AMI 1.5µm process and packaged in 40 pin DIP package. This mixed signal ASIC communicate with sensor chip on one side and with wireless system on the other side.
The in situ monitoring system described finds application in various areas like soil, water, medicines, laboratory research and monitoring of bioreactors.
This thesis work concentrate upon the control logic block interface of the mixed signal ASIC as mentioned above.