JP3298462B2 - Memory bank switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer and a DMA having a memory area comprising a plurality of banks.
(Direct memory access) The present invention relates to a memory bank switching device for automatically switching memory banks by a memory access by a controller.

[0002]

Conventionally, this type of memory bank switching device, for example, as in the conventional example described in JP-A-59 over 90132, the memory bank corresponding to each channel of the microcomputer and a DMA controller ( simply
A "bank" is set in advance, and a switching control circuit for automatically switching the memory bank by memory access from the microcomputer and memory access by DMA transfer is provided.

[0003] However, since the operation of the microcomputer are separate <br/> program read cycle and the execution cycle, when switching to the memory bank that does not place the program in the execution cycle, the following program read cycle, the program Will be accessed . In other words, a program of the microcomputer will not be placed in the memory area <br/> constituting the bank.

Further, since a memory bank is switched for each channel of the DMA controller, bank switching cannot be performed in a memory-to-memory transfer performed in a two-cycle operation of one channel. That is, DMA transfer between different bank memories cannot be performed.

[0005]

As described above, in the conventional memory bank switching device, the program of the microcomputer cannot be arranged in the memory in the bank space, and the DMA transfer between different bank memories cannot be performed. There is a drawback that the weight and the speed of data processing are hindered.

The present invention solves the above-mentioned problems in the conventional technology. A microcomputer program is arranged in a memory in a bank space so that a memory device other than the bank space is not required, and a different memory bank is used. It is an object of the present invention to provide a memory bank switching device that enables a DMA transfer between the memory banks and eliminates the need to once save data in a memory other than the bank space, thereby reducing the size and weight and increasing the speed of data processing.

[0007]

According to a first aspect of the present invention, there is provided a microcomputer and a DMA controller having a memory space comprising a plurality of banks.
In the memory bank switching device memory banks are switched be accessed by chromatography la, the micro competent
For accessing the program memory of the
For accessing a data memory of a computer;
For read memory access by the controller and the DMA controller
Assigned for controller write memory access
A plurality of banks and a program for the microcomputer ;
Bank number of bank corresponding to RAM memory access, corresponding to data memory access of the microcomputer
Bank number of the bank, Li of the DMA controller
Bank number of the bank corresponding to the over-de memory access, and pair a write memory access of the DMA controller
Switching control records that the bank number of the response to bank Ru is set in advance
Register and program memory access or data memory access from the microcomputer;
Switching control for automatically switching banks according to the bank number set in the switching control register by read memory access or write memory access by transfer
And a switching control means having a circuit .

[0008]

The above-described memory bank switching device of the present invention is configured so that the microcomputer and the DMA controller access the selected bank memory via the address bus and the data bus.

[0010] The memory bank switching device having the above-mentioned configuration sets a memory bank number corresponding to a program memory access of the microcomputer, a data memory access, a read memory access for each channel of the DMA controller, and a write memory access in advance, And memory access from a microcomputer and DM
The memory bank is automatically switched by the memory access by the A transfer.

Therefore, the microcomputer program can be arranged in the memory of the bank space, and a memory device other than the bank space is not required. Also, DMA transfer between different memory banks becomes possible, and it is not necessary to save data once to a memory other than the bank space. As a result, a reduction in size and weight and high-speed data processing are performed.

[0012]

Next, an embodiment of a memory bank switching device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a memory bank switching device according to an embodiment of the present invention. In the example shown in FIG. 1, a microcomputer 1 for sending a program cycle / data cycle display signal Sc is connected to the microcomputer 1 via an address bus Sa and a data bus Sb, and a DMA channel display signal Sd and a DMA read / write. And a DMA controller 2 for transmitting the display signal Se.

The microcomputer 1 and the DMA
Controller 2, address bus Sa and data bus Sb
And a bank memory 3 to which a memory bank selection signal Sf is inputted. The microcomputer 1, the DMA controller 2, and the bank memory 3 are connected to each other via an address bus Sa and a data bus Sb. It has a memory bank switching device 4 that receives a program cycle / data cycle display signal Sc from the computer 1 and outputs a memory bank selection signal Sf to the bank memory 3.

FIG. 2 is a block diagram showing a detailed configuration of the memory bank switching device in FIG. In FIG. 2, the memory bank switching device includes a bank number of a bank in which a program executed by the microcomputer 1 is stored, a bank number of a bank in which data accessed by the microcomputer 1 is stored, and each of a DMA controller 2 A switching control register 4a is provided for setting a bank number of a bank assigned to a channel and corresponding to read memory access and write memory access for each channel in advance. That is, the switching control register 4a
Is the program memory access of the microcomputer 1.
Memory bank number, microcomputer
Memory bank number corresponding to 1 data memory access
And the readme for each channel of the DMA controller 2.
Memory bank number corresponding to memory access and DMA
Write memory access for each channel of controller 2
Memory bank number corresponding to each
It has become.

Further, the memory bank switching device 4 receives a program cycle / data cycle display signal Sc from the microcomputer 1, a DMA channel display signal Sd and a DMA read / write display signal Se from the DMA controller 2, and The cycle being executed is determined from the program cycle / data cycle display signal Sc, the DMA channel display signal Sd, and the DMA read / write display signal Se, and the bank is determined according to the memory bank number set in the switching control register 4a. A switching control circuit 4b for outputting a memory bank selection signal Sf to the memory 3 is provided.

Next, the operation of this embodiment will be described. 1 and 2, a microcomputer 1
Sets the bank number of the program memory in the switching control register 4a as an initial operation. Next, the program is run and executed. Thereafter, if necessary, before the access is performed, the bank number of the data memory to be accessed by the microcomputer 1 or the memory bank number corresponding to the read memory access and the write memory access for each channel of the DMA controller 2 before the access is performed. Set.

The switching control circuit 4b receives the program cycle / data cycle display signal Sc from the microcomputer 1, the DMA channel display signal Sd and the DMA read / write display signal Se from the DMA controller 2, and receives these program cycles. / Data cycle display signal Sc, DMA channel display signal Sd and DMA
The cycle being executed is determined from the read / write display signal Se, and the memory bank selection signal Sf is output to the bank memory 3 according to the memory bank number set in the switching control register 4a.

The microcomputer 1 and the DMA controller 2 access the selected bank memory 3 through the address bus Sa and the data bus Sb.

As described above, in this embodiment, the memory bank numbers corresponding to the program memory access of the microcomputer 1, the data memory access, the read memory access of each channel of the DMA controller 2, and the write memory access are set in advance. Further, the memory bank is automatically switched by the memory access from the microcomputer 1 and the memory access by the DMA transfer.

Therefore, the program of the microcomputer 1 can be arranged in the memory in the bank space,
Memory equipment other than the bank space becomes unnecessary. And,
DMA transfer between different memory banks becomes possible, and there is no need to save data once to a memory other than the bank space. As a result, it is possible to reduce the size and weight and to speed up data processing.

[0021]

As is apparent from the above description, according to the memory bank switching device of the present invention, the program memory access of the microcomputer, the data memory access, and the read memory access and the write memory access of each channel of the DMA controller are performed. Is set in advance, and the memory bank is automatically switched by a memory access from the microcomputer and a memory access by DMA transfer.

Thus , the microcomputer program can be arranged in the memory of the bank space, and the memory equipment other than the bank space becomes unnecessary. Also, DMA transfer between different memory banks becomes possible, and it is not necessary to save data once to a memory other than the bank space. As a result, it is possible to reduce the size and weight and to speed up data processing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a memory bank switching device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a memory bank switching device in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 microcomputer 2 DMA controller 3 bank memory 4 memory bank switching device 4a switching control register 4b switching control circuit Sa address bus Sb data bus Sc program cycle / data cycle display signal Sd DMA channel display signal Se DMA read / write display signal Sf memory Bank select signal

Claims (1)

(57) [Claims] A memory space comprising a plurality of banks;
MicrocomputerAnd by the DMA controller
The memory bank to access isSwitchable memory van
In the switching device,Program memory access of the microcomputer
Data memory access of the microcomputer
Memory access of the DMA controller
And the write memory access of the DMA controller.
Multiple banks assigned for each  The microcomputerProgram memory access
Corresponding toThe bank number of the bank and the micro computer
DataData memory accessBank of Bank
number,Read memory access of the DMA controller
The bank number of the bank corresponding toas well asTheDMA controller
Laura'sSupports write memory accessBank Van
Are set in advanceSwitching control register, Said my
From a computerprogramMemory access or
Data memory access,By the DMA transferReadme
Moly access or lightWith memory access,Cut off
Change control registerAutomatically according to the set bank number
Switch banks dynamicallyA switching control circuit.
Replacement control means,  A memory bank switching device, comprising: