Integrated circuit comprising a dac with provision for setting the dac to a clear condition, and a method for setting a dac to a clear condition

Abstract

A multi-channel integrated circuit comprises a plurality of channels (CHto CH). A DAC () is provided in each channel (CHto CH) for converting digital data inputted to the circuit () through an I/O port (). Digital data to be converted by the DACs () is selectively applied to input registers () of each channel (CHto CH) on a digital data bus () under the control of an interface and control logic circuit (). The digital words written to the input registers () are in turn written to DAC registers () through corresponding digital switches () for conversion by the DACs (). A clear code register () stores a clear code for writing to the DAC registers () in response to a clear signal applied to a clear terminal () of the circuit () so that analogue outputs appearing on output terminals () of the channels (CHto CH) are of a predetermined value, typically, zero volts, when the circuit () is set in a clear condition. The clear code is written to the clear code register () through the I/O port () and the interface and control logic circuit ().