Low-Power USB Flash Card Reader Using Bulk-Pipe Streaming with UAS Command Re-Ordering and Channel Separation

• US 20110016267A1
• Filed: 09/21/2010
• Published: 01/20/2011
• Est. Priority Date: 03/17/2004
• Status: Active Grant

• Current Assignee: Super Talent Technology, Corporation
• Original Assignee: Super Talent Electronics, Inc.
• Inventors: Yu, Frank, Ma, Abraham C., Lee, Charles C.
• Granted Patent: US 8,200,862 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G11C 13/0004 comprising amorphous/crystalline phase transition cells
• CPC Class Codes: G11C 16/102 External programming circuits, e.g. EPROM programmers; In-circuit programming or reprogramming; EPROM emulators
• CPC Class Codes: G11C 2216/30 Reduction of number of input/output pins by using a serial interface to transmit or receive addresses or data, i.e. serial access memory
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A flash-card reader improves transmission efficiency by using bulk streaming of multiple pipes. A bulk data-out pipe carries host write data to the card reader and can operate in parallel with a bulk data-in pipe that carries host read data that was read from a flash card attached to the card reader. Status packets do not block data packets since the he status packets are buffered through a separate status pipe, and commands are buffered through a command pipe. Flash data from multiple flash cards are interleaved as separate endpoints that share the bulk data-in pipe. A data in/out streaming state machine controls streaming bulk data through the bulk data-in and data-out pipes, while a status streaming state machine controls streaming status packets through the status pipe. Transaction overhead is reduced using bulk streaming where packets for several commands are combined into the same bulk streams.

Claims

1. A card reader comprising:

a transmit pair for sending packets to a host;

a receive pair for receiving packets from the host;

wherein the transmit and receive pair comprise a differential bus with a first pin carry+signal and a second pin carry−

signal from host as the receive pair, and a second pair differential serial bus with a first pin carry+signal and a second pin carry−

signal to the host as the transmit pair;

an input buffer for buffering packets from the receive pair and for buffering packets to the transmit pair;

a command extractor for extracting commands from the packets from the host;

a command pipe for flowing commands from the host to the card reader;

a status pipe for flowing status packets from the card reader to the host;

a bulk data-out pipe for flowing data packets from the host to the card reader;

a bulk data-in pipe for flowing data packets from the card reader to the host;

bulk endpoint buffers comprising;

a status bulk-in endpoint that sends status packets to the host through the status pipe;

a data bulk-in endpoint that sends data packets to the host through the bulk data-in pipe;

a data bulk-out endpoint that receives data packets from the host through the bulk data-out pipe;

a command endpoint that receives command packets from the host through the command pipe;

a processor for executing control routines;

a chaining direct-memory access (DMA) engine, programmed by the processor to transfer data packets including headers and payloads between the input buffer and the bulk endpoint buffers;

a flash-card socket for receiving a flash memory card; and

a flash-card protocol converter, coupled to the bulk endpoint buffers, for converting commands extracted by the command extractor into flash-card signals for accessing the flash memory card inserted into the flash-card socket,

whereby packets are flowed through pipes using the chaining DMA engine.

2. The card reader of claim 1 wherein data packets for different host commands are identified by a stream identifier in the data packet;

wherein data packets for different host commands are flowed together through the bulk data-in pipe and the bulk data-our pipe,

whereby data packets with different stream identifiers are flowed together through the bulk data-our pipe.

3. The card reader of claim 2 further comprising:

a plurality of flash-card sockets each for receiving a flash memory card;

a plurality of stream buffers, wherein each stream buffer stores packets having a same stream identifier value;

a stream rearrange unit that sorts data packets received by the data bulk-out endpoint into the plurality of stream buffers using the stream identifiers for sorting decisions,

whereby data packets are sorted by stream identifier into the plurality of stream buffers.

4. The card reader of claim 3 further comprising:

a data in/out streaming state machine for controlling streaming of data packets through the bulk data-in pipe and through the bulk data-out pipe; and

a status streaming state machine for controlling streaming of status packets through the status pipe.

5. The card reader of claim 4 wherein the data in/out streaming state machine comprises:

a D-Enter state activated when the host sends a first command to the card reader;

a D-Idle state activated when the card reader sends a not-ready signal to the host;

a D-Start state activated when the card reader sends a ready signal to the host;

a D-Burst state activated while the host is bursting data packets to the card reader.

6. The card reader of claim 4 wherein the status streaming state machine comprises:

a S-Enter state activated when the card reader sends an acknowledgement to the host;

a S-Idle state activated when the card reader sends a not-ready signal to the host;

a S-Start state activated when the card reader sends a ready signal to the host;

a S-Burst state activated while the card reader is bursting status packets to the host.

7. The card reader of claim 3 further comprising:

a plurality of flash physical layers coupled between the plurality of flash-card sockets and a plurality of the flash-card protocol converter.

8. The card reader of claim 3 wherein the input buffer comprises a plurality of first-in-first-out (FIFO) buffers.

9. The card reader of claim 3 further comprising:

an arbiter, coupled to the command extractor and the input buffer, for activating a blocking flag when addresses for commands overlap.

10. The card reader of claim 3 further comprising:

a low-power physical layer for driving packets to the transmit pair and for receiving packets from the receive pair;

a low-power link layer, coupled to the low-power physical layer, for generating and processing link control words for controlling link power and for link training; and

a protocol layer for pointing to headers and payloads in the bulk endpoint buffers for transfer to the low-power link layer.

11. The card reader of claim 10 wherein the low-power physical layer further comprises:

a driver for driving the transmit pair with a transmit data stream;

a bit clock for clocking bits of the transmit data stream;

a parallel-to-serial converter, clocked by the bit clock, for converting data bytes for transmission to serial data for transmission by the driver;

a receiver for detecting signal transitions on the receive pair;

a receive clock recovery circuit, coupled to the receiver, for generating a received bit clock from signal transitions detected by the receiver;

a symbol boundary detector for detecting boundaries of symbols received by the receiver;

a serial-to-parallel converter, clocked by the received bit clock, for converting an extracted data stream to received data bytes; and

an elastic buffer for storing the received data bytes.

12. The card reader of claim 11 wherein the low-power physical layer further comprises:

a low-frequency periodic signal generator, receiving the bit clock, for generating a low-frequency periodic signal;

a mux, receiving the low-frequency periodic signal and receiving the transmit data stream, for applying the low-frequency periodic signal to the driver when a power-down mode is enabled, and for applying the transmit data stream to the driver when the power-down mode is not enabled.

13. The card reader of claim 11 further comprising:

a Universal-Serial-Bus (USB) socket for receiving a cable with the transmit pair and the receive pair;

wherein the low-power physical layer comprises a USB 3.0 physical layer;

wherein the flash-card protocol converter converts USB to a flash card interface.

14. A bulk streaming device comprising:

a Universal-Serial-Bus (USB) port for connecting to a host over a receive pair and a transmit pair of lines;

a physical layer coupled to the USB port to receive a received data stream from the receive pair, and to transmit a transmit data stream to the transmit pair;

a link layer, coupled to the physical layer, for processing link control words received from the host over the receive pair, for controlling link power and link training;

a first-in-first-out (FIFO) buffer, coupled to the link layer, for storing packets passed through the link layer;

a command pipe for flowing commands from the host to the bulk streaming device;

a status pipe for flowing status packets from the bulk streaming device to the host;

a bulk data-out pipe for flowing data packets from the host to the bulk streaming device;

a bulk data-in pipe for flowing data packets from the bulk streaming device to the host;

a RAM buffer for storing status packets and data packets, the RAM buffer including bulk endpoint buffers that comprise;

a status bulk-in endpoint that sends status packets to the host through the status pipe;

a data bulk-in endpoint that sends data packets to the host through the bulk data-in pipe;

a data bulk-out endpoint that receives data packets from the host through the bulk data-out pipe;

a command endpoint that receives command packets from the host through the command pipe;

a processor for executing control routines;

a direct-memory access (DMA) engine, programmed by the processor to transfer data packets including headers and payloads between the FIFO buffer and the bulk endpoint buffers;

a plurality of port sockets each for connecting to a downstream peripheral; and

a traffic repeater, coupled to the bulk endpoint buffers, for converting commands from the host into peripheral signals for accessing the downstream peripheral inserted into a port socket,

whereby packets are flowed through pipes using the DMA engine.

15. The bulk streaming device of claim 14 wherein the downstream peripheral comprises a flash memory card or a USB device.

16. The bulk streaming device of claim 14 further comprising:

a read-only memory (ROM), coupled to the processor, for storing control instructions for the control routines executed by the processor.

17. The bulk streaming device of claim 14 wherein the link layer further comprises:

a sequence number generator for generating sequence numbers for link packets;

a CRC generator/checker for generating and checking link CRC'"'"'s;

a link power manager, responsive to link control words from the host, for managing link power on the transmit pair; and

a link trainer, responsive to link training patterns from the host, for configuring the receive pair and the transmit pair.

18. The bulk streaming device of claim 14 wherein the receive pair and the transmit pair together comprise a set of two pairs of differential serial buses, a first pair bus with a first pin carry+signal and a second pin carry−

signal, and a second pair differential serial bus with a first pin carry +signal and a second pin carry−

signal.

19. The bulk streaming device of claim 18 wherein the physical layer further comprises:

an 8/10-bit encoder/decoder for converting 10-bit symbols from the received data stream into 8-bit received data bytes, and for converting 8-bit transmit data bytes into 10-bit transmit symbols to form the transmit data stream; and

a descrambler for descrambling the 8-bit received data bytes and for scrambling the 8-bit transmit data bytes.

20. A bulk-streaming card reader comprising:

transmit pair means for sending packets to a host;

receive pair means for receiving packets from the host;

wherein the transmit pair means and receive pair means comprise a differential bus with a first pin carry+signal and a second pin carry−

signal from host as the receive pair means, and a second pair differential serial bus with a first pin carry+signal and a second pin carry−

signal to the host as the transmit pair means;

input buffer means for buffering data packets from the receive pair means and for buffering packets to the transmit pair means;

command extractor means for extracting commands from the packets from the host;

command pipe means for flowing commands from the host to the bulk-streaming card reader;

status pipe means for flowing status packets from the bulk-streaming card reader to the host;

bulk data-out pipe means for flowing data packets from the host to the bulk-streaming card reader;

bulk data-in pipe means for flowing data packets from the bulk-streaming card reader to the host;

bulk endpoint buffers comprising;

status bulk-in endpoint means for storing status packets for transmission to the host through the status pipe means;

data bulk-in endpoint means for storing data packets for transmission to the host through the bulk data-in pipe means;

data bulk-out endpoint means for storing data packets received from the host through the bulk data-out pipe means;

command endpoint means for storing command packets received from the host through the command pipe means;

processor means for executing control routines;

direct-memory access (DMA) means, programmed by the processor means, for transferring data packets including headers and payloads between the input buffer means and the bulk endpoint buffers;

a flash-card socket for receiving a flash memory card;

flash-card protocol converter means, coupled to the bulk endpoint buffers, for converting commands extracted by the command extractor means into flash-card signals for accessing the flash memory card inserted into the flash-card socket;

data in/out streaming state machine means for controlling streaming of data packets through the bulk data-in pipe means and through the bulk data-out pipe means; and

status streaming state machine means for controlling streaming of status packets through the status pipe means,

whereby packets are flowed through pipes.

21. The bulk-streaming card reader of claim 20 further comprising:

a plurality of a flash-card sockets each for receiving a flash memory card.