Control device with mode flags for dedicating memory segments as either

Abstract

An output control device for an internal combustion engine has a plurality of registers connected to a data bus. These registers comprise registers for holding output request time data specifying when the generation of output signals will be requested, and mask data specifying whether the registers are reserved for output operations or may be used as working RAM. Other registers are provided for holding output request time data, mask data, and channel designating data specifying the output channel on which output signals will be generated. Unloading of the data in these registers is performed by sequentially supplying gate switching control signals from a shifter to gates connected to these registers. The output request time data is compared with absolute time data from a timer by a comparator, and a coincidence signal indicating coincidence detection is applied to a mask gate together with the mask data. Whether to accept the coincidence data or not is determined according to the value of the mask data. Selectors are also included for determining whether to use the coincidence signal to request an output control signal at a predetermined output channel or at an output channel designated by the channel designating data. The output request data selected through these selectors is supplied to the corresponding output port through flip-flops.