different parameters and the periodic display thereof application_number US 5622479 A description fig1 is a block diagram of a display system comprising a central processing unit cpu 2 a random access memory ram 4 a read only memory rom a mask register 12 a presetable counter 14 being operated as a timer a status register 16 an or gate 18 and gates 28 to 34 sensors 42 to 46 a voltage frequency convertor 48 displays 36 to 40 a control bus an address bus and a data bus the sensor 42 detects pulses which are generated in synchronization with an engine shaft rotation the sensor 44 detects pulses which are generated in synchronization with a wheel speed of a vehicle the sensor 46 detects temperature of an engine and generates an output voltage in correspondence with the engine temperature a v f convertor generates pulses having a frequency which is proportional to the input voltage therefore the combination of the sensor 46 and the v f convertor generates serial pulses whose frequency is changed in accordance with the temperature of the engine the pulses delivered from sensors 42 and 44 as well as v f convertor 48 are applied the respective stages of the status register 16 having 4 stages in all through the and gates 30 to 34 respectively an output pulse from the preset counter 14 is also applied to a stage of the status register through the and gate 28 the combination of the mask register 12 and and gates 28 to 34 is used in this embodiment to stop the operation for setting into the status register 16 the pulses from all but one of the preset counter 14 the sensors 42 and 44 and the v f convertor 48 when the status register 16 receives.