US 6,317,352 B1 · Apparatus for implementing a buffered daisy chain connection between a memory controller and memory modules

Abstract

A plurality of memory modules interface through a daisy-chain providing a point-to-point connection for each memory module. The first and the last memory module in the daisy chain each connect to a separate memory controller port forming a ring circuit. A distinct set of signals connect the memory modules in each direction. A junction circuit in each memory module provides line isolation, a coupling to the adjoining memory modules in the daisy chain, or in the case of the first and last memory module in the daisy chain, a memory module and a memory controller, and a data synchronization circuit. Each junction circuit provides as well as voltage conversion so that the memory devices on a memory module operate at a different voltage than the memory controller, and multiplexing/de-multiplexing so that a lesser number of lines interface with each junction circuit.

Claims10

Dependent claims

A first memory module comprising:

at least one memory device;
a junction circuit having a first port to couple to a bus that includes data lines characterized by at least one of at least one memory-data line and at least one non-memory-data line;
a second port coupled to the memory devices;
a third port to couple to a second memory module;
to send data received from the first port to both the second port and the third port, to send data received from the second port to the first port, and to send data received from the third port to the first port, and that includes an isolation circuit to provide a point-to-point connection to the first port and the third port.

2 more elements

A memory system comprising:

(a) a first memory module that includes
at least one first memory device;
a junction circuit having a first port to couple to a bus that includes data lines characterized by at least one of at least one memory-data line and at least one non-memory-data line;
a second port coupled to the first memory devices;
a third port coupled to a second memory module;
to send data received from the first port to both the second port and the third port, to send data received from the second port to the first port, and to send data received from the third port to the first port, and that includes an isolation circuit to provide a point-to-point connection to the first port and the third port;
and
(b) the second memory module that includes
at least one second memory device;
a second junction circuit having a fourth port coupled via a bus to the third port, a fifth port coupled to the second memory devices to send data received from the fourth port to the fifth port and send data received from the fifth port to the fourth port;
and an isolation circuit to provide a point-to-point connection to the fourth port.

8 more elements

Dependencies are inferred from the claim text.

Apparatus for implementing a buffered daisy chain connection between a memory controller and memory modules

Life of this patent

Apparatus for implementing a buffered daisy chain connection between a memory controller and memory modules

Life of this patent

Abstract

Claims10