Semiconductor memory device in which use of cache can be selected

• US 6,381,190 B1
• Filed: 05/11/2000
• Issued: 04/30/2002
• Est. Priority Date: 05/13/1999
• Status: Expired due to Term

• Current Assignee: Longitude Licensing Limited (Vector Capital Corporation)
• Original Assignee: NEC Corporation
• Inventors: Shinkai, Eiji
• Primary Examiner(s): KIM, HONG CHONG
• Application Number:
  US09/568,747
• Time in Patent Office: 719 Days
• Field of Search: 365/230.03, 365/189.04, 365/189.03, 365/189.01, 711/104, 710/22, 710/27, 710/28, 710/38, 710/107
• US Class Current: 365/189.14
• CPC Class Codes: G11C 11/4076 Timing circuits for regeneration management G11C11/406
• CPC Class Codes: G11C 2207/2245 Memory devices with an internal cache buffer
• CPC Class Codes: G11C 2207/229 Timing of a write operation
• CPC Class Codes: G11C 7/1051 Data output circuits, e.g. read-out amplifiers, data output buffers, data output registers, data output level conversion circuits
• CPC Class Codes: G11C 7/106 Data output latches
• CPC Class Codes: G11C 7/1072 for memories with random access ports synchronised on clock signal pulse trains, e.g. synchronous memories, self timed memories

Abstract

A semiconductor memory device, includes a plurality of banks, each of which includes a memory cell array and a sense amplifier section, a plurality of channel memories, a data control circuit, a first bus provided between the plurality of banks and the plurality of channel memories, a second bus provided between the plurality of channel memories and the data control circuit, and a third bus between the plurality of banks and the data control circuit. The data control circuit outputs write data to the sense amplifier section of a specified one of the plurality of banks via the third bus in a direct write access mode, and inputs read data from the sense amplifier section of a specified one of the plurality of banks via the third bus in a direct read access mode. Also, the data control circuit outputs write data to the sense amplifier section of a specified one of the plurality of banks via the second bus, a specified one of the plurality of channel memories and the first bus in an indirect write access mode, and inputs read data from the sense amplifier section of a specified one of the plurality of banks via the first bus, a specified one of the plurality of channel memories and the second bus in an indirect read access mode.

Claims

1. A semiconductor memory device, comprising:

a plurality of banks, each of which includes a memory cell array and a sense amplifier section;

a plurality of channel memories;

a data control circuit;

a first bus provided between said plurality of banks and said plurality of channel memories;

a second bus provided between said plurality of channel memories and said data control circuit; and

a third bus between said plurality of banks and said data control circuit, and

wherein said data control circuit outputs write data to said sense amplifier section of a specified one of said plurality of banks via said third bus in a direct write access mode, inputs read data from said sense amplifier section of a specified one of said plurality of banks via said third bus in a direct read access mode, outputs write data to said sense amplifier section of a specified one of said plurality of banks via said second bus, a specified one of said plurality of channel memories and said first bus in an indirect write access mode, and inputs read data from said sense amplifier section of a specified one of said plurality of banks via said first bus, a specified one of said plurality of channel memories and said second bus in an indirect read access mode.

2. A semiconductor memory device according to claim 1, wherein each of said first to third buses includes a bus driver, and

said bus drivers of said first and second buses are set to an enable state in said indirect write access mode and said indirect read access mode, and set to a disable state in said direct write access mode and said direct read access mode, and

said bus driver of said third bus is set to an enable state in said direct write access mode and said direct read access mode, and set to a enable state in said indirect write access mode and said indirect read access mode.

3. A semiconductor memory device according to claim 2, wherein said data control circuit includes a flag used to specify one of an indirect access mode and a direct access mode based on an access mode specify internal command, wherein said indirect access mode includes said indirect write access mode and said indirect read access mode, and said direct access mode includes said direct write access mode and said direct read access mode.

4. A semiconductor memory device according to claim 3, further comprising:

an internal command generating section generating said access mode specify internal command based on a signal supplied to a first specific external input terminal.

5. A semiconductor memory device according to claim 4, wherein said internal command generating section generates an operation mode specify internal command based on signals supplied to second specific external input terminals to set one of a write mode and a read mode.

6. A semiconductor memory device according to claim 3, further comprising:

an internal command generating section generating said access mode specify internal command based on signals supplied to specific external input terminals.

7. A method of accessing a semiconductor memory device, comprising:

setting a direct write access mode in response to a direct access internal command and a write internal command;

setting a direct read access mode in response to said direct access internal command and a read internal command;

setting an indirect write access mode in response to an indirect access internal command and said write internal command;

setting an indirect read access mode in response to said indirect access internal command and said read internal command;

accessing a specific memory cell array such that write data externally supplied is written into said specific memory cell array via a data control circuit, a first bus and a sense amplifier section for said specific memory cell array in said direct write access mode;

accessing said specific memory cell array such that read data is read out from said specific memory cell array via said sense amplifier section for said specific memory cell array, said first bus, and said data control circuit in said direct read access mode;

accessing said specific memory cell array such that said write data externally supplied is written into said specific memory cell array via said data control circuit, a second bus, a specific channel memory, a third bus and said sense amplifier section for said specific memory cell array in said indirect write access mode; and

accessing said specific memory cell array such that read data is read out from said specific memory cell array via said sense amplifier section for said specific memory cell array, said third bus, said specific channel memory, said second bus, and said data control circuit in said indirect read access mode.

8. A method according to claim 7, wherein each of said first to third buses includes a bus driver, and

wherein each of said setting a direct write access mode and said setting a direct read access mode includes:

setting said bus drivers of said second and third buses to a disable state; and

setting said bus drivers of said first bus to an enable state, and

wherein each of said setting an indirect write access mode and said setting an indirect read access mode includes;

setting said bus drivers of said second and third buses to an enable state; and

setting said bus drivers of said first bus to a disable state.

9. A method according to claim 7, further comprising:

selectively generating one of said direct access internal command and said indirect access internal command based on a signal supplied to a first specific external input terminal.

10. A method according to claim 9, further comprising:

selectively generating one of said write internal command and said read internal command based on signals supplied to second specific external input terminals.

11. A method according to claim 7, further comprising:

selectively generating one of said direct access internal command, said indirect access internal command, said write internal command and said read internal command based on signals supplied to second specific external input terminals.

12. A data processing system comprising:

a control unit determining whether or not data processing is to be executed for a data block, generating an external direct access command when it is determined that said data processing is to be executed for said data block, and generating an external indirect access command when it is determined that said data processing is not executed for said data block; and

a semiconductor memory device setting one of an indirect write access mode, an indirect read access mode, a direct write access mode and a direct read access mode based on said external direct access command or said external direct access command, and whether said data processing relates to a write operation or a read operation, and

wherein said semiconductor memory device comprises;

a plurality of banks, each of which includes a memory cell array and a sense amplifier section, and a specific one of said plurality of banks for said data block including a specific memory cell array and a specific sense amplifier section;

a plurality of channel memories;

a data control circuit;

a first bus provided between said plurality of banks and said plurality of channel memories;

a second bus provided between said plurality of channel memories and said data control circuit; and

a third bus between said plurality of banks and said data control circuit, and

wherein said data control circuit sends first write data of said data block from said control unit to said specific sense amplifier section via said third bus in said direct write access mode, receives first read data of said data block from said specific sense amplifier section via said third bus in said direct read access mode, sends second write data to said sense amplifier section of a specified one of said plurality of banks via said second bus, a specified one of said plurality of channel memories and said first bus in said indirect write access mode, and receives second read data from said sense amplifier section of a specified one of said plurality of banks via said first bus, a specified one of said plurality of channel memories and said second bus in said indirect read access mode.

13. A data processing system according to claim 12, wherein each of said first to third buses includes a bus driver, and

said bus drivers of said first and second buses are set to an enable state in said indirect write access mode and said indirect read access mode, and set to a disable state in said direct write access mode and said direct read access mode, and

said bus driver of said third bus is set to an enable state in said direct write access mode and said direct read access mode, and set to a enable state in said indirect write access mode and said indirect read access mode.

14. A data processing system according to claim 13, wherein said data control circuit includes a flag used to specify one of an indirect access mode and a direct access mode based on an access mode specify internal command, wherein said indirect access mode includes said indirect write access mode and said indirect read access mode, and said direct access mode includes said direct write access mode and said direct read access mode.

15. A data processing system according to claim 14, wherein said semiconductor memory device further comprises:

an internal command generating section generating said access mode specify internal command based on said external indirect access command or said external direct access command from said control unit.

16. A data processing system according to claim 15, wherein said internal command generating section generates an operation mode specify internal command based on whether said data processing is for said write operation and said read operation.