Memory controller for daisy chained memory chips
View Patent ↗A memory controller configured to control a daisy chain of memory chips. The memory controller receives read and write requests from a processor, determines a daisy chain of memory chips that the request is directed to, determines which memory chip in the chain of memory chips the request is directed to, and transmits an address/command word recognizable by the correct memory chip. The memory controller sends write data words to the daisy chain of memory chips that can be associated by the correct memory chip for writing into the correct memory chip. The memory controller receives read data words from the daisy chain of memory chips and returns the read data to the processor. The memory controller transmits a bus clock to the daisy chain of memory chips for controlling transmission of address/command words and data words.
1. A memory controller for a daisy chain of memory chips comprising
a processor bus control configured to receive a request from a processor for a memory access to a memory and further configured to receive a data from the processor when the request is a write, and to transmit data to the processor when the request is a read;
an address/command bus port;
a data bus port;
a bus clock port;
an address/command generator configured to transmit an address/command word from the address/command bus port, the address/command word further comprising:
a command;
a packet id;
and
an address;
and
a data send/receive configured to transmit a data word to a daisy chain of memory chips, the data word containing the data sent by the processor the data word further comprising a packet ID;
the data send/receive further configured to receive a data word on the data bus port from the daisy chain of memory chips;
wherein the memory controller fills in a value in a packet ID in an address/command word for a write and a value in a packet ID in a data word such that a memory chip is able to associate the address command word and the data word.
2. The memory controller of claim 1 further configured to associate an address command word for a read with a data word received at the data bus port using the packet ID in the data word received at the data bus port.
3. The memory controller of claim 2 , configured to receive a first request for a first data from the processor, subsequently receive a second request for a second data from the processor, receive the second data from the daisy chain of memory chips, subsequently receive the first data from the daisy chain of memory chips, transmit the first data to the processor, and subsequently transmit the second data to the processor.
4. The memory controller of claim 1 , further configured to determine which chip in the daisy chain of memory chips an address/command word is directed to and configured to write a chip ID value into a chip ID field in the address/command word.
5. The memory controller of claim 1 wherein the chip ID field is a portion of the address.