Semiconductor device
A semiconductor device in which unwanted change in the secondary data which must be reliable is suppressed and the need for a considerable increase in the capacity of a memory unit can be avoided. Also it ensures efficient data processing by asymmetric access to the memory unit. It includes a memory unit having a first memory without an error correcting function, a second memory with an error correcting function, and a plurality of access nodes for the memories. A plurality of buses is coupled to the access nodes and a plurality of data processing modules can asymmetrically access the memory unit through the buses. The first memory stores primary data before data processing by the data processing modules, and the second memory stores secondary data after data processing by the data processing modules.
1. A semiconductor device comprising:
a memory unit having a first memory without an error correcting function, a second memory with an error correcting function, a plurality of access nodes and a plurality of memory local buses;
a plurality of buses coupled to the plurality of access nodes of the memory unit; and
a plurality of data processing modules each of which is configured to perform data processing,
wherein the plurality of memory local buses include a first memory local bus, a second memory local bus, and a third memory local bus,
wherein the plurality of data processing modules include a data processing module and an accelerator specialized in processing of specific data,
wherein the plurality of buses include an accelerator bus coupled to the accelerator, a single master bus coupled to the data processing module and the third memory local bus, and a multi-master bus coupled to the accelerator and the data processing module, and
wherein while externally supplied second data is stored in the first memory through the first memory local bus, the accelerator reads first data from the first memory through the accelerator bus and the second memory local bus to enable first data processing.
2. The semiconductor device according to claim 1 ,
wherein the data processing module and the accelerator are data processing modules which each process a program and can asymmetrically access the first and second memories.
3. The semiconductor device according to claim 1 , further comprising
a direct memory input circuit which performs control to write data supplied from outside the semiconductor device in the first and second memories.
4. The semiconductor device according to claim 1 ,
wherein while the externally supplied second data is stored in the first memory through the first memory local bus, the accelerator further stores first intermediate result data as a result of the first data processing in the second memory through the accelerator bus and the second memory local bus.
5. The semiconductor device according to claim 4 ,
wherein while externally supplied third data is stored in the first memory through the first memory local bus, the accelerator further reads the second data from the first memory through the accelerator bus and the second memory local bus to enable second data processing and the data processing module reads the first intermediate result data from the second memory through the third memory local bus and the single master bus to enable third data processing.
6. The semiconductor device according to claim 5 ,
wherein while the externally supplied third data is stored in the first memory through the first memory local bus, the accelerator further stores second intermediate result data as a result of the second data processing in the second memory through the accelerator bus and the second memory local bus and the data processing module further stores first final result data as a result of the third data processing in the second memory through the third memory local bus and the single master bus.
7. The semiconductor device according to claim 6 ,
wherein while externally supplied fourth data is stored in the first memory through the first memory local bus, the accelerator further reads the third data from the first memory through the accelerator bus and the second memory local bus to enable fourth data processing and the data processing module reads the second intermediate result data from the second memory through the third memory local bus and the single master bus to enable fifth data processing.
8. The semiconductor device according to claim 7 ,
wherein while the externally supplied fourth data is stored in the first memory through the first memory local bus, the accelerator further stores third intermediate result data as a result of the fourth data processing in the second memory through the accelerator bus and the second memory local bus and the data processing module further stores second final result data as a result of the fifth data processing in the second memory through the third memory local bus and the single master bus.
9. The semiconductor device according to claim 8 ,
wherein the first to fourth data are forward image data supplied from an in-vehicle camera.
10. The semiconductor device according to claim 9 , further comprising an in-vehicle network terminal interface,
wherein the data processing module sequentially sends out the first final result data and the second final result data stored in the second memory through the in-vehicle network terminal interface.