Apparatus and method for communicating with semiconductor devices of a serial interconnection
View Patent ↗A system controller communicates with devices in a serial interconnection. The system controller sends a read command, a device address identifying a target device in the serial interconnection and a memory location. The target device responds to the read command to read data in the location identified by the memory location. Read data is provided as an output signal that is transmitted from a last device in the serial interconnection to a data receiver of the controller. The data receiver establishes acquisition instants relating to clocks in consideration of a total flow-through latency in the serial interconnection. Where each device has a clock synchronizer, a propagated clock signal through the serial interconnection is used for establishing the acquisition instants. The read data is latched in response to the established acquisition instants in consideration of the flow-through latency, valid data is latched in the data receiver.
1. A method for communicating with a serial interconnection including a plurality of series-connected semiconductor devices, each of the devices having a clock synchronizer, the devices in the serial interconnection including a first device and a last device, the method comprising:
supplying a clock signal for operation of the devices in the serial interconnection, the clock signal being supplied to the first device and propagated through the clock synchronizers of the devices of the serial interconnection;
sending first instruction information for identifying a target device in the serial interconnection;
enabling the target device by sending an enable signal that is propagated through the serial interconnection;
sending second instruction information for identifying an operation for the target device to perform, the target device operating in accordance with the second instruction information to provide response data, the response data appearing in an output signal from the last device, wherein sending the second instruction information comprises issuing an access command destined for the target device so that the target device performs the operation in accordance with the access command and provides the response data;
establishing an acquisition instant in response to the propagated enable signal and the propagated clock signal; and
capturing the response data in the output signal from the last device in response to the acquisition instant.
2. The method of claim 1 , wherein the step of issuing comprises issuing a read command as the access command and each of the devices includes a memory, the method further comprising:
sending third instruction information to the serial interconnection, the third instruction information identifying a location in memory, the first, second and third instruction information being contained in a command string,
in response to the read command as the second instruction information contained in the command string, the target device reading data from a memory location in the memory of the target device, the memory location being identified by the third instruction information, the read data being provided as the response data.
3. An apparatus for communicating with a serial interconnection including a plurality of series-connected semiconductor devices, each of the devices having a clock synchronizer, the serial interconnection including a first device and a last device, the apparatus comprising:
a controller for (i) providing a clock signal for operation of the devices in the serial interconnection, the clock signal being provided to the first device and propagated through the clock synchronizers of the devices of the serial interconnection, (ii) sending first instruction information to the serial interconnection, the first instruction information identifying a target device in the serial interconnection, (iii) sending an enable signal to enable the target device, the enable signal being propagated through the serial interconnection, and (iv) sending second instruction information to the serial interconnection, the second information identifying an operation for the target device to perform, the target device operating in accordance with the second instruction information to provide response data, the response data appearing in an output signal from the last device, wherein the second instruction information comprises an access command destined for the target device so that the target device performs the operation in accordance with the access command and provides the response data; and
a receiver for receiving the output signal from the last device, the receiver comprising:
acquisition establishing circuitry for establishing an acquisition instant relating to the clock signal, the acquisition establishing circuitry comprising a clock producer for producing a latch clock signal having latch clocks in response to the propagated clock signal from the last device and the propagated enable signal; and
signal latching circuitry for latching the output signal at the acquisition instant to capture the response data, the signal latching circuitry comprising data latching circuitry for latching the output signal containing the response data in response to the latch clock signal to capture the response data.
4. The apparatus of claim 3 , wherein the clock producer comprises:
delay circuitry for delaying at least one of the propagated clock signal and the propagated enable signal; and
logic circuitry for performing a logic operation on the delayed or non-delayed propagated clock signal and the delayed or non-delayed propagated enable signal to produce the latch clocks.
5. The apparatus of claim 4 , wherein:
the delay circuitry comprises
transfer circuitry for transferring the propagated enable signal in response to the clock signal to provide the delayed propagated enable signal; and
a delay element for delaying the propagated clock signal to provide the delayed propagated clock signal; and
the logic circuitry comprises AND logic circuitry for performing an AND operation on the delayed propagated clock signal and the delayed propagated enable signal to produce the latch clocks.
6. The apparatus of claim 3 , wherein the signal latching circuitry further comprises data delay circuitry for delaying the output signal containing the response data, the delayed output signal being provided to the data latching circuitry to capture the response data.
7. The apparatus of claim 6 , wherein the clock producer further comprises:
delay circuitry for delaying the propagated enable signal;
a phase shifter for shifting in phase of the propagated clock signal; and
logic circuitry for performing a logic operation on the delayed propagated enable signal and the phase-shifted propagated clock signal to produce the latch clocks.
8. The apparatus of claim 7 , wherein:
the logic circuitry comprises AND logic circuitry for performing an AND logic operation on the delayed propagated enable signal and the phase-shifted propagated clock signal to provide the latch clock signal, the latching circuitry capturing the response data in response to the latch clock signal.
9. The apparatus of claim 3 , wherein:
each of the devices includes a memory;
the controller is capable of:
issuing a read command as the access command; and
sending third instruction information to the serial interconnection, the third instruction information identifying a memory location in memory; and
the target device reads data from the memory location in the memory of the target device in accordance with the third instruction information in response to the read command and provides the read data as the response data.