COUNTER DEVICE

PURPOSE:To correct the value of a counter which is being operated with high accuracy by providing an adding means for adding a correction necessary value of the counter written by a software and the present value of the counter and writing its result in the counter. CONSTITUTION:When read-out/write of a reload register 1 are executed by a software, a delivery of data is executed between a data bus 4 and the reload register 1. On the other hand, when write to a counter 2 is executed by the software, a data transfer is executed from the data bus 4 to a counter buffer 11. When the data is written in the counter buffer 11, an adding circuit 12 adds the contents of the counter buffer 11, namely, a correction necessary value of the counter 2, and the present value of the counter 2, and writes back its result to the counter 2. Also, when read-out of the counter 2 is executed by the software, a data transfer is executed from the counter 2 to the data bus 4. In such a way, the counter which is being operated can be executed with high accuracy, and a load of a processor can be reduced.