Physical device (PHY) support of the USB2.0 link power management addendum using a ULPI PHY interface standard
View Patent ↗A protocol may enable support of the USB 2.0 LPM (Link Power Management) Addendum by a ULPI PHY (Universal Serial Bus Transceiver Macrocell Low-Pin Interface Physical Layer Device), facilitating transmitting the reserved PID (Physical Interface Device) token, used in the LPM Extended Transaction, through a ULPI bus. Bits [ 3:0 ] of a ULPI Tx Cmd (Transmit Command) byte may be reused, with the value of those bits being 4′b0 for a transmission (normally indicating a No PID transmission), by configuring the ULPI PHY to qualify the selected four Tx Cmd bits (bits [ 3:0 ] of the Tx Cmd) with the Opmode code. The ULPI PHY may thereby interpret bits [ 3:0 ] of the Tx Cmd byte based on the value of the Opmode, and may not transmit the Extended PID when the Opmode is set to 2′b10, that is, when the Opmode is indicative of bit-stuffing and NRZI encoding being disabled, for example during a Chirp transmission. When the Opmode code is set to 2′b0, indicative of normal bit-stuffing, and the Tx Cmd bits [ 3:0 ] are set to 4′b0 during a transmission (Tx Cmd bits[ 7:6 ]=2′b01), then the PHY may transmit the Extended PID, followed by the rest of the extended transaction onto a USB.
1. A system comprising:
a first bus;
a second bus;
a transceiver coupled to the first bus; and
a device coupled to the first bus and the second bus;
wherein the transceiver is configured to initiate a data transfer to the device by transmitting onto the first bus a first code indicative of a data transmission and further indicative of data to be transmitted not having a physical interface device (PID) code;
wherein the transceiver is further configured to transmit onto the first bus, as part of the data transfer, a reserved PID code and corresponding one or more packets subsequent to transmitting the first code; and
wherein the device is configured to receive the first code and the reserved PID code and corresponding one or more packets, wherein the device is further configured to qualify the first code with a function control code, and when the function control code is indicative of normal operation, transmit the reserved PID code and corresponding one or more packets onto the second bus.
2. The system of claim 1 , wherein the reserved PID code is an extended PID token of a Link Power Management (LPM) Extension Token Transaction, and the corresponding one or more packets comprise ULPI (Universal Serial Bus Transceiver Macrocell Low-Pin Interface) extended transaction packets.
3. The system of claim 1 wherein the second bus is a USB (Universal Serial Bus), and the first bus is a standard ULPI (USB Transceiver Macrocell Low-Pin Interface) bus.
4. The system of claim 1 , wherein the transceiver is a USB (Universal Serial Bus) Link, and the device is a ULPI PHY (USB Transceiver Macrocell Low-Pin Interface Physical Layer Device).
5. The system of claim 1 , wherein the first code is comprised in a ULPI (USB Transceiver Macrocell Low-Pin Interface) transmit command byte.
6. The system of claim 5 , wherein the value of the ULPI transmit command byte is 8′b01000000.
7. The system of claim 1 , wherein the function control code is a ULPI (USB Transceiver Macrocell Low-Pin Interface) operation mode (OpMode) code.
8. A USB (Universal Serial Bus) Link comprising:
a ULPI I/O (USB Transceiver Macrocell Low-Pin Interface Input/Output) interface configured to enable the USB Link to transmit and/or receive information over a ULPI bus; and
USB Link protocol logic configured to:
enable the USB Link to initiate data transfer on the ULPI bus by transmitting through the ULPI I/O interface a first code indicative of a data transmission and further indicative of data to be transmitted not having a physical interface device (PID) code; and
enable the USB Link to transmit onto the ULPI bus through the ULPI I/O interface, as part of the initiated data transfer, a reserved PID code and corresponding one or more packets subsequent to transmitting the first code;
wherein the reserved PID code is indicative of a request for a target device of the initiated data transfer to transition to a different state.
9. The USB Link of claim 8 , further comprising one or more buffers configured to store information outgoing and incoming through the ULPI I/O interface.
10. The USB Link of claim 8 , wherein the information transmitted and/or received by the USB Link over the ULPI bus comprises data packets of USB transactions.
11. A ULPI PHY (Universal Serial Bus Transceiver Macrocell Low-Pin Interface Physical Layer Device) comprising:
ULPI interface control logic configured to enable the ULPI PHY to transmit and/or receive information over a ULPI bus; and
a function control register configured to store information indicative of the modes of operation of the USB PHY;
wherein the ULPI PHY is configured to receive over the ULPI interface:
a first code indicative of a data transmission and further indicative of data to be transmitted not having a physical interface device (PID) code; and
a reserved PID code and corresponding one or more packets subsequent to receiving the first code;
wherein the ULPI PHY is further configured to transmit the reserved PID code and corresponding one or more packets onto a USB, when contents of the function control register are indicative of normal mode of operation.
12. The ULPI PHY of claim 11 , further comprising transceiver logic configured to interface with the USB and to at least partially manage transmitting and receiving packets of the USB PHY over the USB.
13. A method for transmitting an extended transaction, the method comprising:
initiating a data transfer, comprising transmitting onto a first bus a first code indicative of a data transmission and further indicative of data to be transmitted not having a physical interface device (PID) code;
transmitting onto the first bus, as part of the data transfer, a reserved PID code and corresponding one or more packets, subsequent to said transmitting the first code;
receiving the first code and the reserved PID code and corresponding one or more packets;
qualifying the first code with a function control code; and
when the function control code is indicative of normal operation, transmitting the reserved PID code and corresponding one or more packets onto a second bus.
14. The method of claim 13 , wherein said transmitting the first code comprises transmitting a ULPI (Universal Serial Bus Transceiver Macrocell Low-Pin Interface) transmit command byte indicative of a No PID data transmission.
15. The method of claim 13 , wherein said transmitting onto the first bus the reserved PID code comprises transmitting an LPM (Link Power Management) Extended PID token, and wherein said transmitting the corresponding one or more packets comprises transmitting at least an LPM token packet and extended token packet.
16. The method of claim 13 , wherein said transmitting the reserved PID code and corresponding one or more packets onto the second bus comprises a ULPI PHY (Universal Serial Bus Transceiver Macrocell Low-Pin Interface Physical Layer Device) transmitting an LPM token packet and extended token packet onto a USB.
17. A system comprising:
a USB (Universal Serial Bus) Link configured to:
initiate data transfer on a ULPI (USB Transceiver Macrocell Low-Pin Interface) bus by transmitting a first code indicative of a data transmission and further indicative of data to be transmitted not having a physical interface device (PID) code; and
transmit onto the ULPI bus, as part of the data transfer, a reserved PID code and corresponding one or more packets subsequent to transmitting the first code; and
a ULPI PHY (ULPI Physical Layer Device) configured to:
store a function control code;
receive the first code;
receive the reserved PID code and corresponding one or more packets subsequent to receiving the first code; and
transmit the reserved PID code and corresponding one or more packets onto a USB, when the control function code is indicative of a normal mode of operation.
18. The system of claim 17 , wherein the USB Link is comprised on a system-on-chip (SOC).
19. The system of claim 18 , wherein the ULPI PHY is configured on the SOC.
20. The system of claim 17 , wherein the USB Link and ULPI PHY are comprised in one or more of:
a USB Host device;
a USB on-the-go (OTG) device;
a USB hub;
a computer system;
an HSIC (High-Speed Interchip USB) interface; and
a system using a ULPI interface.
21. The system of claim 17 , wherein the reserved PID code is indicative of a request for a target device of the initiated data transfer to transition to a different state.