Synchronous communication between system in package (SiP) devices
View Patent ↗A source clock signal is received from a primary semiconductor device by a secondary semiconductor device via an interconnect. A local clock signal is generated on the secondary semiconductor device based on the source clock signal. A mode control signal is generated on the secondary semiconductor device, where the mode control signal indicates one of an unlock mode of operation and a lock mode of operation of the secondary semiconductor device. A physical interface (PHY) clock signal is generated based on the local clock signal, where the PHY clock signal includes the local clock signal during the lock mode, and the PHY clock signal includes an inverted version of the local clock signal during the unlock mode. Data received from the primary semiconductor device via the interconnect is latched at a positive edge of the PHY clock signal during the unlock mode and the lock mode.
1. A semiconductor device comprising:
locking control logic implemented on a physical interface of the semiconductor device, wherein the locking control logic is configured to
generate a mode control signal that indicates one of an unlock mode of operation and a lock mode of operation of the semiconductor device; and
interconnect circuitry implemented on the physical interface, wherein the interconnect circuitry comprises:
clock generation circuitry coupled to an interconnect and configured to
receive a local clock signal that is generated on the semiconductor device based on a source clock signal that is received from a host semiconductor device via the interconnect, and
output a physical interface (PHY) clock signal based on the local clock signal, wherein
the PHY clock signal comprises the local clock signal during the lock mode of operation, and
the PHY clock signal comprises an inverted version of the local clock signal during the unlock mode of operation, and
a first flip flop (FF) having an input coupled to the interconnect to receive data from the interconnect, having a clock input coupled to the PHY clock signal, and configured to latch the data at a positive edge of the PHY clock signal during the unlock mode of operation and the lock mode of operation.
2. The semiconductor device of claim 1 , wherein the interconnect circuitry further comprises:
a second FF having a clock input configured to receive the local clock signal, having an input coupled to an output of the first FF to receive the data from the first FF, and configured to latch the data on the positive edge of the local clock signal during the unlock mode of operation and the lock mode of operation.
3. The semiconductor device of claim 2 , wherein the interconnect circuitry further comprises:
a multiplexer having a first input coupled to the output of the first FF, having a second input coupled to an output of the second FF, and configured to
select the first input during the lock mode of operation, and
select the second input during the unlock mode of operation.
4. The semiconductor device of claim 3 , wherein the interconnect circuitry further comprises:
an isolation circuit having an input coupled to the output of the multiplexer, having an output coupled to internal circuitry of the semiconductor device, and configured to isolate the data selected by the multiplexer from the internal circuitry during a transition process from the unlock mode to the lock mode.
5. The semiconductor device of claim 1 , wherein the interconnect circuitry further comprises:
a clock alignment block configured to
generate the local clock signal based on the source clock signal received from the interconnect, wherein
the local clock signal is not aligned with the source clock signal during the unlock mode of operation, and
the local clock signal is aligned with the source clock signal during the lock mode of operation.
6. The semiconductor device of claim 1 , wherein the interconnect circuitry further comprises:
a level shifter coupled to the interconnect, having an output coupled to the input of the first FF, and configured to shift a voltage level of the received source clock signal and the data received from the interconnect.
7. The semiconductor device of claim 1 , wherein
the locking control logic is further configured to
generate the mode control signal that indicates the unlock mode of operation in response to a startup process of the semiconductor device,
generate an isolation control signal in response to a stall acknowledge signal received from the host semiconductor device, and
generate the mode control signal that indicates the lock mode of operation after the stall acknowledge signal is cleared.
8. The semiconductor device of claim 1 , wherein
the local clock signal comprises a clock frequency equal to or greater than 400 Mhz during the lock mode of operation, and
the local clock signal comprises a clock frequency below 400 Mhz during the unlock mode of operation.
9. A semiconductor device comprising:
locking control logic implemented on a physical interface of the semiconductor device, wherein the locking control logic is configured to
generate a mode control signal that indicates one of an unlock mode of operation and a lock mode of operation of the semiconductor device; and
interconnect circuitry implemented on the physical interface, wherein the interconnect circuitry comprises:
clock generation circuitry coupled to an interconnect and configured to
receive a first local clock signal that is generated on the semiconductor device based on a first source clock signal that is received from a host semiconductor device via the interconnect, and
output a physical interface (PHY) clock signal based on the first local clock signal, wherein
the PHY clock signal comprises the first local clock signal during the lock mode of operation, and
the PHY clock signal comprises an inverted version of the first local clock signal during an unlock mode of operation;
a first hold flip flop (FF) having an input coupled to the interconnect to receive first data associated with a first data signal, having a clock input coupled to the PHY clock signal, and configured to latch the first data at a positive edge of the PHY clock signal; and
a second hold FF having an input coupled to the interconnect to receive second data associated with a second data signal, having a clock input coupled to the PHY clock signal, and configured to latch the second data at the positive edge of the PHY clock signal, wherein
the first hold FF and the second hold FF are configured to respectively latch the first data and the second data on sequential positive edges of the PHY clock signal during the unlock mode of operation and the lock mode of operation.
10. The semiconductor device of claim 9 , wherein the interconnect circuitry further comprises:
a first FF having an input coupled to an output of the first hold FF to receive the first data from the first hold FF, having a clock input coupled to a second local clock signal, and configured to latch the first data on a positive edge of the second local clock signal, wherein
the second local clock signal is generated on the semiconductor device based on a second source clock signal that is received from the host semiconductor device via the interconnect, and
the first local clock signal is faster than the second local clock signal; and
a second FF having an input coupled to an output of the second hold FF to receive the second data from the second hold FF, having a clock input coupled to the second local clock signal, and configured to latch the second data on the positive edge of the second local clock signal.
11. The semiconductor device of claim 10 , wherein the interconnect circuitry further comprises:
a multiplexer having a first input coupled to the output of the second FF hold, having a second input coupled to an output of the second FF, and the multiplexer configured to
select the first input during the lock mode of operation, and
select the second input during the unlock mode of operation.
12. The semiconductor device of claim 11 , wherein the interconnect circuitry further comprises:
a first isolation circuit having an input coupled to an output of the first FF, having an output coupled to internal circuitry of the semiconductor device, and configured to isolate the first data from the internal circuitry during a transition process from the unlock mode to the lock mode; and
a second isolation circuit having an input coupled to an output of the multiplexer, having an output coupled to internal circuitry of the semiconductor device, and configured to isolate the data selected by the multiplexer from the internal circuitry during the transition process.
13. The semiconductor device of claim 9 , wherein the interconnect circuitry further comprises:
a clock alignment block configured to
generate the first local clock signal based on the first source clock signal received from the interconnect, wherein
the first local clock signal is not aligned with the source clock signal during the unlock mode of operation, and
the first local clock signal is aligned with the source clock signal during the lock mode of operation.
14. The semiconductor device of claim 9 , wherein the interconnect circuitry further comprises:
a level shifter coupled to the interconnect, having an output coupled to the input of the first hold FF and to the input of the second hold FF, and configured to shift a voltage level of the first source clock signal, the first data, and the second data received from the interconnect.
15. The semiconductor device of claim 9 , wherein
the locking control logic is further configured to
generate the mode control signal that indicates the unlock mode of operation in response to a startup process of the semiconductor device,
generate a isolation control signal in response to a stall acknowledge signal received from the host semiconductor device, and
generate the mode control signal that indicates the lock mode of operation after the stall acknowledge signal is cleared.
16. The semiconductor device of claim 9 , wherein
the first local clock signal comprises a clock frequency equal to or greater than 400 Mhz during the lock mode of operation, and
the first local clock signal comprises a clock frequency below 400 Mhz during the unlock mode of operation.
17. A method comprising:
receiving a source clock signal from a primary semiconductor device, wherein
the source clock signal is received by a secondary semiconductor device via an interconnect coupling the primary and secondary semiconductor devices;
generating a local clock signal on the secondary semiconductor device based on the source clock signal;
generating a mode control signal on the secondary semiconductor device, wherein
the mode control signal indicates one of an unlock mode of operation and a lock mode of operation of the secondary semiconductor device;
generating a physical interface (PHY) clock signal based on the local clock signal,
wherein
the PHY clock signal comprises the local clock signal during the lock mode of operation, and
the PHY clock signal comprises an inverted version of the local clock signal during the unlock mode of operation; and
latching data received from the primary semiconductor device via the interconnect,
wherein
the latching is performed at a positive edge of the PHY clock signal during the unlock mode of operation and the lock mode of operation.
18. The method of claim 17 , further comprising:
latching second data received from the primary semiconductor device via the interconnect, wherein
the latching second data is performed on a sequential positive edge of the PHY clock signal during the unlock mode of operation and the lock mode of operation.
19. The method of claim 17 , further comprising:
generating the mode control signal that indicates the unlock mode of operation in response to a startup process of the secondary semiconductor device; and
generating a transition control signal on the secondary semiconductor device in response to stall communication with the primary semiconductor device, wherein
the stall communication is initiated by the primary semiconductor device in response to detecting that a phase-locked loop circuit of the primary semiconductor device is locked, and
the transition control signal is configured to stall the latching data.
20. The method of claim 17 , further comprising:
generating the mode control signal that indicates the lock mode of operation in response to lock communication with the primary semiconductor device, wherein
the lock communication is initiated by the primary semiconductor device in response to an oscillator of the primary semiconductor device reaching a minimum clock frequency, and
the local clock signal is aligned with the source clock signal during the lock mode of operation.