| 摘要 |
PURPOSE:To diagnose a peripheral controller without decreasing processing efficiency, by providing a direct memory access controller with two channels, using one for memory loading and the other for memory storage, and storing information in each of them. CONSTITUTION:One direct memory access controller DMAC is provided with the two channels CH-A and CH-B corresponding to plural peripheral controllers PD-A and PD-B. A central processing unit CPU uses the channel CH-A for memory loading, and the channel CH-B for memory storage, and stores pieces of information of a transfer starting address N, number of transfer bytes, and transfer direction of data. Once the CPU indicates the diagnosis start of the PD-A, the PD-A stores data in another area (following the address N) in a memory MEM through a return part RT without the intervention of a storage device. When the PD-B is diagnosed, data is transferred over a channel other than the CH-B and compared. |
