| 摘要 |
PURPOSE:To select the outputs of clock oscillators in accordance with the monitoring output of a minitoring circuit and to prevent malfunction due to the stop of outputs from the oscillators by providing the titled device with a monitoring circuit stretching oscillation outputs and continuing the outputs in accordance with plural clock oscillators. CONSTITUTION:Oscillation outputs from plural clock osciollators 11, 12 are inputted to function blocks A, B. When the inputs are changed from ''0'' to ''1'' by stretching circuits 13, 15, 18, 20, NOT circuits 14, 19 and AND circuits 16, 21 in respective blocks A, B, outputs are simultaneously generated. When the inputs are changed from ''1'' to ''0'', the outputs are changed from ''1'' to ''0'' after stretching the inputs for a prescribed time and the ''0'' is outputted. The outputs of the blocks A, B are supplied to an OR circuit 26 and also inputted to AND circuits 17, 23 to which the outputs of the oscillators 11, 12 are also inputted. The outputs of the oscillators 11, 12 are selected in accordance with the outputs of the respective blocks A, B and OR is outputted from the OR circuit 26. Thus, malfunction due to the stop of outputs from the oscillators 11, 12 is prevented. |
