title: A system-on-chip digital pH meter for use in a wireless diagnostic capsule.
abstract: This paper describes the design and implementation of a system-on-chip digital pH meter, for use in a wireless capsule application. The system is organized around an 8-bit microcontroller, designed to be functionally identical to the Motorola 6805. The analog subsystem contains a floating-electrode ISFET, which is fully compatible with a commercial CMOS process. On-chip programmable voltage references and multiplexors permit flexibility with the minimum of external connections. The chip is designed in a modular fashion to facilitate verification and component re-use. The single-chip pH meter can be directly connected to a personal computer, and gives a response of 37 bits/pH, within an operating range of 7 pH units.
authors.affiliation: Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow G12 8LT, UK. p.hammond@elec.gla.ac.uk
authors.forename: Paul A
authors.initials: PA
authors.lastname: Hammond
authors.forename: Danish
authors.initials: D
authors.lastname: Ali
authors.forename: David R S
authors.initials: DR
authors.lastname: Cumming
mesh_terms: D000465:Algorithms; D002214:Capsules; D020099:Coated Materials, Biocompatible; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005764:Gastroesophageal Reflux / Q000175:diagnosis; D005766:Gastrointestinal Contents / Q000737:chemistry; D006801:Humans; D017736:Ion-Selective Electrodes; D008838:Microcomputers; D008904:Miniaturization; D018670:Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods; D019736:Prostheses and Implants; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D018511:Systems Integration; D013686:Telemetry / Q000295:instrumentation* / Q000379:methods; D014159:Transducers
chemical_list: D002214:Capsules; D020099:Coated Materials, Biocompatible