data path 502 the count values provided by the serial shifters 226 of respective sensors are thus moved sequentially along path 502 to the control unit 104 conceptually the input of sensor 0 is tied to ground while the output of the last sensor along the path 502 is connected to the control unit 104 usefully the control unit is provided with a 19 bit wide shift register 504 respective data packets containing count values are parallel loaded thereinto as they arrive at control unit 104 in a useful alternative arrangement the thermal sensors 110 are arranged in a number of groups such as four groups in this arrangement the output of each group is connected to the control unit 104 before going to the input of the next following group along path 502 thus the output of sensor group 0 is connected to the control unit before going to the input of sensor group 1 this enables the control unit to multiplex around a sensor group that has become disabled as an example fig5 shows the control macro providing a path 506 around the core 1 group fig5 further shows control unit 104 provided with a processor 508 and a programmable computer readable medium 510 in addition to controller 116 and register 504 programmable medium 510 contains instructions to be read by processor 508 whereupon processor 508 directs control unit 104 and other components of system 102 to operate as described above when incoming count value data is coupled to threshold unit 106 logic therein looks at the incoming data to determine the associated sensor identification if the temperature value indicated by the incoming count value is.