Semiconductor memory device suitable for interconnection in a ring topology
View Patent ↗A semiconductor memory device, which comprises: memory; a plurality of inputs for receiving a command latch enable signal, an address latch enable signal, an information signal and a select signal indicative of whether the memory device has been selected by a controller; a plurality of outputs for releasing a set of output signals towards a next device; control circuitry; and bypass circuitry. When the select signal is indicative of the memory device having been selected by the controller, the control circuitry is configured to interpret the information signal based on the command latch enable signal and the address latch enable signal. When the select signal is indicative of the memory device not having been selected by the controller, the bypass circuitry is configured to transfer the command latch enable signal, the address latch enable signal and the information signal to the outputs of the memory device.
1. A system, comprising:
a point-to-point ring topology comprising a plurality of semiconductor memory devices; and
a controller for communicating with the devices, said controller comprising:
a plurality of outputs for providing to a first one of the devices a command latch enable signal, an address latch enable signal and an information signal;
a plurality of outputs for independently providing a respective select signal to each of the devices;
control logic configured to select a particular one of the devices and to issue specific information to the particular one of the devices by controlling the command latch enable signal, the address latch enable signal and the information signal provided to the first device, wherein when the particular one of the devices is not the first one of the devices, the command latch enable signal, the address latch enable signal and the information signal are daisy-chained from the first one of the devices to the particular one of the devices via the point-to-point ring topology; and
wherein the control logic is further configured to convey via the select signal independently provided to the particular one of the devices that the particular one of the devices has been selected while conveying via the select signals independently provided to the other devices that the other devices have not been selected.
2. The system defined in claim 1 , wherein the specific information comprises a command cycle forming part of a command.
3. The system defined in claim 2 , wherein the command is one of a PAGE READ command, a RANDOM DATA OUTPUT command, a PAGE PROGRAM command, a RANDOM DATA INPUT command, a BLOCK ERASE command, a RESET command and a READ STATUS command.
4. The system defined in claim 2 , wherein to issue the specific information, the control logic is configured to assert the command latch enable signal, to de-assert the address latch enable signal and to encode the command cycle into the information signal.
5. The system defined in claim 1 , wherein the specific information comprises an address cycle forming part of an address.
6. The system defined in claim 5 , wherein to issue the specific information, the control logic is configured to de-assert the command latch enable signal, to assert the address latch enable signal and to encode the address cycle into the information signal.
7. The system defined in claim 1 , wherein the specific information comprises data to be written to the particular one of the devices following issuance of a command to write data to the particular one of the devices.
8. The system defined in claim 7 , wherein to issue the specific information, the control logic is configured to assert both the command latch enable signal and the address latch enable signal and to sequentially place onto the information signal portions of the data to be written to the particular one of the devices.
9. The system defined in claim 8 , wherein the controller further comprises an output for providing a mode signal to the particular one of the devices, wherein the control logic is further configured to convey, via the mode signal and during issuance of the data to be written to the particular one of the devices, a request that the particular one of the devices operate in a write mode.
10. The system defined in claim 1 , wherein the control logic is further configured to issue a prompt to retrieve data from the particular one of the devices by controlling the command latch enable signal and the address latch enable signal following issuance of a read command to read data from the particular one of the devices.
11. The system defined in claim 10 , wherein to issue the prompt, the control logic is configured to assert both the command latch enable signal and the address latch enable signal after a read time period has elapsed following issuance of the read command to read data from the particular one of the devices.
12. The system defined in claim 11 , the controller further comprising an output for providing a mode signal to the particular one of the devices, wherein the control logic is further configured to convey, via the mode signal and during issuance of the prompt to retrieve data from the particular one of the devices, a request that the particular one of the devices operate in a read mode.
13. The system defined in claim 11 , wherein the controller further comprises a plurality of inputs for receiving a set of input signals from a second one of the devices.
14. The system defined in claim 13 , wherein the control logic is further configured to receive, via the inputs, data output by the particular one of the devices in response to issuance of the prompt.
15. A method, comprising:
providing a command latch enable signal, an address latch enable signal and an information signal to a first device among a plurality of semiconductor memory devices arranged in a point-to-point ring topology;
independently providing a respective select signal to each of the devices of the topology;
selecting a particular one of the devices of the topology;
issuing specific information to the particular one of the devices by controlling the command latch enable signal, the address latch enable signal and the information signal provided to the first device, wherein when the particular one of the devices is not the first device, the command latch enable signal, the address latch enable signal and the information signal are daisy-chained from the first device to the particular one of the devices via the point-to-point ring topology;
conveying via the select signal independently provided to the particular one of the devices that the particular one of the devices has been selected; and
conveying via the select signals independently provided to the other devices that the other devices have not been selected.