USB的Bandwidth與throughput - GaryLee
USB的Bandwidth與throughput
出自GaryLee
跳轉到: 導航, 搜尋
在寫USB相關應用的時候，有時先了解bandwidth與throughput的限制，會比較有利於日後的開發。這裡簡單的列出了USB的bandwidth與throughput。
USB Bandwidth & HID throughtput 速度 Bandwidth(bits/s) HID throughput(bytes/sec/report) HID throughput(bytes/microframe/I/O report) Remark
Low Speed 1.5M 800 8
Full Speed 12M 64,000 64
High Speed 480M 23.4M 3072
REF: http://www.edacn.net/html/86/49586-52367.html
2011年7月31日 星期日
What does GT/s mean, anyway? - 2007-03-01 07:00:00 | Test & Measurement World
What does GT/s mean, anyway? - 2007-03-01 07:00:00 | Test & Measurement World
When announcing version 2.0 of the PCI Express (PCIe) standard in January, the PCI Special Interest Group (PCI-SIG) said that the new version “doubles the interconnect bit rate from 2.5 GT/s to 5 GT/s.” Most of us are used to seeing bus speeds specified in Gbps, or gigabits per second, but GT/s stands for gigatransfers per second. What’s the difference?
The difference has to do with the encoding of the data. Because PCIe is a serial bus with the clock embedded in the data, it needs to ensure that enough level transitions (1 to 0 and 0 to 1) occur for a receiver to recover the clock. To increase level transitions, PCIe uses “8b/10b” encoding, where every eight bits are encoded into a 10-bit symbol that is then decoded at the receiver. Thus, the bus needs to transfer 10 bits to send 8 bits of encoded data.
Looking at a single PCIe 1.1 lane, the bidirectional bus can transfer 2.5 Gbps in each direction, or 5 Gbps in total. Because the bus needs to send 10 bits of encoded data for every 8 bits of unencoded data, the effective bit rate is
5 Gbps • (8/10), or 4 Gbps
A 16-lane PCIe 1.1 bus can transfer 80 Gbps of encoded data or 64 Gbps of unencoded data. Because PCIe 2.0 doubles the transfer rate, a single lane can transfer 5 Gbps of unencoded data in each direction, or 10 Gbps of unencoded data in total. That’s 8 Gbps encoded. Thus, a 16-lane PCIe 2.0 bus transfers 160 Gbps unencoded, which is 128 Gbps of encoded data. That’s 16 Gbytes/s of encoded data.
So, when the PCI-SIG announced the new rate of 5 GT/s, it was referring to raw data rate—the number of bps that the bus can move, or transfer. The encoding process reduces the rate of useful data transferred over the bus to 80% of the bus’s raw speed.
Links to more about PCI Express, data encoding, and transfer rates: The PCI-SIG Web site contains the announcement of PCI Express 2.0 specification. www.pcisig.com/specifications/pciexpress/base2.
For an explanation of 8b/10b encoding, see “Encoding Dictionary, terms, and definitions,” www.interfacebus.com/Definitions1.html.
For an overview of the PCI Express bus, see “PCI Express Technology,” a white paper from Dell Computer, www.dell.com/content/topics/global.aspx/vectors/en/2004_pciexpress.
When announcing version 2.0 of the PCI Express (PCIe) standard in January, the PCI Special Interest Group (PCI-SIG) said that the new version “doubles the interconnect bit rate from 2.5 GT/s to 5 GT/s.” Most of us are used to seeing bus speeds specified in Gbps, or gigabits per second, but GT/s stands for gigatransfers per second. What’s the difference?
The difference has to do with the encoding of the data. Because PCIe is a serial bus with the clock embedded in the data, it needs to ensure that enough level transitions (1 to 0 and 0 to 1) occur for a receiver to recover the clock. To increase level transitions, PCIe uses “8b/10b” encoding, where every eight bits are encoded into a 10-bit symbol that is then decoded at the receiver. Thus, the bus needs to transfer 10 bits to send 8 bits of encoded data.
Looking at a single PCIe 1.1 lane, the bidirectional bus can transfer 2.5 Gbps in each direction, or 5 Gbps in total. Because the bus needs to send 10 bits of encoded data for every 8 bits of unencoded data, the effective bit rate is
5 Gbps • (8/10), or 4 Gbps
A 16-lane PCIe 1.1 bus can transfer 80 Gbps of encoded data or 64 Gbps of unencoded data. Because PCIe 2.0 doubles the transfer rate, a single lane can transfer 5 Gbps of unencoded data in each direction, or 10 Gbps of unencoded data in total. That’s 8 Gbps encoded. Thus, a 16-lane PCIe 2.0 bus transfers 160 Gbps unencoded, which is 128 Gbps of encoded data. That’s 16 Gbytes/s of encoded data.
So, when the PCI-SIG announced the new rate of 5 GT/s, it was referring to raw data rate—the number of bps that the bus can move, or transfer. The encoding process reduces the rate of useful data transferred over the bus to 80% of the bus’s raw speed.
Links to more about PCI Express, data encoding, and transfer rates: The PCI-SIG Web site contains the announcement of PCI Express 2.0 specification. www.pcisig.com/specifications/pciexpress/base2.
For an explanation of 8b/10b encoding, see “Encoding Dictionary, terms, and definitions,” www.interfacebus.com/Definitions1.html.
For an overview of the PCI Express bus, see “PCI Express Technology,” a white paper from Dell Computer, www.dell.com/content/topics/global.aspx/vectors/en/2004_pciexpress.
2011年7月30日 星期六
2011年7月29日 星期五
What is 802.11h? - Definition from Whatis.com
What is 802.11h? - Definition from Whatis.com
1.Dynamic frequency selection (DFS) detects the presence of other devices on a channel and automatically switches the network to another channel if and when such signals are detected.
2.Transmit power control (TPC) reduces the radio-frequency (RF) output power of each network transmitter to a level that minimizes the risk of interference to and from other systems, while still allowing satisfactory network performance.
1.Dynamic frequency selection (DFS) detects the presence of other devices on a channel and automatically switches the network to another channel if and when such signals are detected.
2.Transmit power control (TPC) reduces the radio-frequency (RF) output power of each network transmitter to a level that minimizes the risk of interference to and from other systems, while still allowing satisfactory network performance.
Wi-Fi - 维基百科，自由的百科全书
Wi-Fi - 维基百科，自由的百科全书
目前Wi-Fi聯盟所公佈的認證種類有：
WPA/WPA2：WPA/WPA2是基於IEEE 802.11a、802.11b、802.11g的單模、雙模或雙頻的產品所建立的測試程式。內容包含通訊協定的驗證、無線網路安全性機制的驗證，以及網路傳輸表現與相容性測試。
WMM（Wi-Fi MultiMedia）：當影音多媒體透過無線網路的傳遞時，要如何驗證其頻寬保證的機制是否正常運作在不同的無線網路裝置及不同的安全性設定上是WMM測試的目的。
WMM Power Save：在影音多媒體透過無線網路的傳遞時，如何透過管理無線網路裝置的待命時間來延長電池壽命，並且不影響其功能性，可以透過WMM Power Save的測試來驗證。
WPS（Wi-Fi Protected Setup）：這是一個2007年年初才發布的認證，目的是讓消費者可以透過更簡單的方式來設定無線網路裝置，並且保證有一定的安全性。目前WPS允許透過Pin Input Config（PIN）、Push Button Config（PBC）、USB Flash Drive Config（UFD）以及Near Field Communication Contactless Token Config（NFC）的方式來設定無線網路裝置。
ASD（Application Specific Device）：這是針對除了無線網路存取點（Access Point）及站台（Station）之外其他有特殊應用的無線網路裝置，例如DVD播放器、投影機、印表機等等。
CWG（Converged Wireless Group）：主要是針對Wi-Fi mobile converged devices的RF部分測量的測試程式。
Wi-Fi Direct
目前Wi-Fi聯盟所公佈的認證種類有：
WPA/WPA2：WPA/WPA2是基於IEEE 802.11a、802.11b、802.11g的單模、雙模或雙頻的產品所建立的測試程式。內容包含通訊協定的驗證、無線網路安全性機制的驗證，以及網路傳輸表現與相容性測試。
WMM（Wi-Fi MultiMedia）：當影音多媒體透過無線網路的傳遞時，要如何驗證其頻寬保證的機制是否正常運作在不同的無線網路裝置及不同的安全性設定上是WMM測試的目的。
WMM Power Save：在影音多媒體透過無線網路的傳遞時，如何透過管理無線網路裝置的待命時間來延長電池壽命，並且不影響其功能性，可以透過WMM Power Save的測試來驗證。
WPS（Wi-Fi Protected Setup）：這是一個2007年年初才發布的認證，目的是讓消費者可以透過更簡單的方式來設定無線網路裝置，並且保證有一定的安全性。目前WPS允許透過Pin Input Config（PIN）、Push Button Config（PBC）、USB Flash Drive Config（UFD）以及Near Field Communication Contactless Token Config（NFC）的方式來設定無線網路裝置。
ASD（Application Specific Device）：這是針對除了無線網路存取點（Access Point）及站台（Station）之外其他有特殊應用的無線網路裝置，例如DVD播放器、投影機、印表機等等。
CWG（Converged Wireless Group）：主要是針對Wi-Fi mobile converged devices的RF部分測量的測試程式。
Wi-Fi Direct
Wi-Fi - 维基百科，自由的百科全书
Wi-Fi - 维基百科，自由的百科全书
目前Wi-Fi聯盟所公佈的認證種類有：
WPA/WPA2：WPA/WPA2是基於IEEE 802.11a、802.11b、802.11g的單模、雙模或雙頻的產品所建立的測試程式。內容包含通訊協定的驗證、無線網路安全性機制的驗證，以及網路傳輸表現與相容性測試。
WMM（Wi-Fi MultiMedia）：當影音多媒體透過無線網路的傳遞時，要如何驗證其頻寬保證的機制是否正常運作在不同的無線網路裝置及不同的安全性設定上是WMM測試的目的。
WMM Power Save：在影音多媒體透過無線網路的傳遞時，如何透過管理無線網路裝置的待命時間來延長電池壽命，並且不影響其功能性，可以透過WMM Power Save的測試來驗證。
WPS（Wi-Fi Protected Setup）：這是一個2007年年初才發布的認證，目的是讓消費者可以透過更簡單的方式來設定無線網路裝置，並且保證有一定的安全性。目前WPS允許透過Pin Input Config（PIN）、Push Button Config（PBC）、USB Flash Drive Config（UFD）以及Near Field Communication Contactless Token Config（NFC）的方式來設定無線網路裝置。
ASD（Application Specific Device）：這是針對除了無線網路存取點（Access Point）及站台（Station）之外其他有特殊應用的無線網路裝置，例如DVD播放器、投影機、印表機等等。
CWG（Converged Wireless Group）：主要是針對Wi-Fi mobile converged devices的RF部分測量的測試程式。
Wi-Fi Direct
目前Wi-Fi聯盟所公佈的認證種類有：
WPA/WPA2：WPA/WPA2是基於IEEE 802.11a、802.11b、802.11g的單模、雙模或雙頻的產品所建立的測試程式。內容包含通訊協定的驗證、無線網路安全性機制的驗證，以及網路傳輸表現與相容性測試。
WMM（Wi-Fi MultiMedia）：當影音多媒體透過無線網路的傳遞時，要如何驗證其頻寬保證的機制是否正常運作在不同的無線網路裝置及不同的安全性設定上是WMM測試的目的。
WMM Power Save：在影音多媒體透過無線網路的傳遞時，如何透過管理無線網路裝置的待命時間來延長電池壽命，並且不影響其功能性，可以透過WMM Power Save的測試來驗證。
WPS（Wi-Fi Protected Setup）：這是一個2007年年初才發布的認證，目的是讓消費者可以透過更簡單的方式來設定無線網路裝置，並且保證有一定的安全性。目前WPS允許透過Pin Input Config（PIN）、Push Button Config（PBC）、USB Flash Drive Config（UFD）以及Near Field Communication Contactless Token Config（NFC）的方式來設定無線網路裝置。
ASD（Application Specific Device）：這是針對除了無線網路存取點（Access Point）及站台（Station）之外其他有特殊應用的無線網路裝置，例如DVD播放器、投影機、印表機等等。
CWG（Converged Wireless Group）：主要是針對Wi-Fi mobile converged devices的RF部分測量的測試程式。
Wi-Fi Direct
2011年7月28日 星期四
Linksys E4200 support - TomatoUSB
Linksys E4200 support - TomatoUSB
Re: Linksys E4200 support
Toastman_BKK 10 Feb 2011, 19:41 GMT+08
Photos and information:
http://www.smallnetbuilder.com/wireless/wireless-reviews/31399-cisco-linksys-e4200-maximum-performance-wireless-n-router-reviewed
http://infodepot.wikia.com/wiki/Linksys_E4200_v1.0#Pictures
- CPU: Broadcom BCM4718 @ 480 MHz
- Switch: Broadcom BCM53115
- RAM: 64 MB
- Flash: 16 MB
- 2.4 GHz: uses the internal radio of the BCM4718 - with two SiGe 2528L 2.4 GHz power amps max output 250mW 2x3 MIMO
- 5 GHz: Broadcom BCM4331 Single-Chip 802.11n Transceiver 3x3 MIMO plus 3x SE2594L complete front end modules - rated at max output 125mW
http://www.sige.com/files/SE2594L%20Datasheet%20Rev%201p3.pdf
They have tried to do the best they can as regards spacing with the rather small internal antennas, which appear to be horizontally mounted dipoles for 5GHz and short loaded dipoles for 2.4GHz. There are onboard connectors for 5GHz but the 2.4GHz antennas are soldered to the PCB in these photos. J18 and J19 are probably intended for OEM test connectors.
See also http://tomatousb.org/forum/t-299811/linksys-e4200-available-now
Re: Linksys E4200 support
Toastman_BKK 10 Feb 2011, 19:41 GMT+08
Photos and information:
http://www.smallnetbuilder.com/wireless/wireless-reviews/31399-cisco-linksys-e4200-maximum-performance-wireless-n-router-reviewed
http://infodepot.wikia.com/wiki/Linksys_E4200_v1.0#Pictures
- CPU: Broadcom BCM4718 @ 480 MHz
- Switch: Broadcom BCM53115
- RAM: 64 MB
- Flash: 16 MB
- 2.4 GHz: uses the internal radio of the BCM4718 - with two SiGe 2528L 2.4 GHz power amps max output 250mW 2x3 MIMO
- 5 GHz: Broadcom BCM4331 Single-Chip 802.11n Transceiver 3x3 MIMO plus 3x SE2594L complete front end modules - rated at max output 125mW
http://www.sige.com/files/SE2594L%20Datasheet%20Rev%201p3.pdf
They have tried to do the best they can as regards spacing with the rather small internal antennas, which appear to be horizontally mounted dipoles for 5GHz and short loaded dipoles for 2.4GHz. There are onboard connectors for 5GHz but the 2.4GHz antennas are soldered to the PCB in these photos. J18 and J19 are probably intended for OEM test connectors.
See also http://tomatousb.org/forum/t-299811/linksys-e4200-available-now
2011年7月27日 星期三
2011年7月26日 星期二
2011年7月25日 星期一
2011年7月24日 星期日
USB HSIC
What is HSIC?
HSIC (High-Speed Inter-Chip) is an industry standard for USB chip-to-chip interconnect with a 2-signal (strobe, data) source synchronous serial interface using 240 MHz DDR signaling to provide only high-speed (480 Mbps data rate). No external cables or connectors and hot plug-n-play are supported. There is also no analog transceivers, and hence reduces the complexity, cost, power consumption, and manufacturing risk. Low power can be achieved with 1.2 V LVCMOS signaling levels instead of the 3.3 V signaling requirement. Both data and strobe are bi-directional utilizing NRZI encoding. In addition, HSIC interface is always operated at high speed, 480 Mbps. Hence, no high-speed chirp protocol is needed during enumeration. Finally, HSIC USB is fully compatible with existing USB software stacks and provides all data transfer needs through a single unified USB software stack. For more technical information regarding the requirements to implement a HSIC USB solution, please refer to the High-Speed Inter-Chip USB Electrical Specification, Version 1.0 (a supplement to the USB 2.0 specification.) which is now available online at http://www.usb.org/developers/docs/docs
http://www.synopsys.com/dw/dwtb/hsic_usb2_device/hsic_usb2_device.html
HSIC (High-Speed Inter-Chip) is an industry standard for USB chip-to-chip interconnect with a 2-signal (strobe, data) source synchronous serial interface using 240 MHz DDR signaling to provide only high-speed (480 Mbps data rate). No external cables or connectors and hot plug-n-play are supported. There is also no analog transceivers, and hence reduces the complexity, cost, power consumption, and manufacturing risk. Low power can be achieved with 1.2 V LVCMOS signaling levels instead of the 3.3 V signaling requirement. Both data and strobe are bi-directional utilizing NRZI encoding. In addition, HSIC interface is always operated at high speed, 480 Mbps. Hence, no high-speed chirp protocol is needed during enumeration. Finally, HSIC USB is fully compatible with existing USB software stacks and provides all data transfer needs through a single unified USB software stack. For more technical information regarding the requirements to implement a HSIC USB solution, please refer to the High-Speed Inter-Chip USB Electrical Specification, Version 1.0 (a supplement to the USB 2.0 specification.) which is now available online at http://www.usb.org/developers/docs/docs
http://www.synopsys.com/dw/dwtb/hsic_usb2_device/hsic_usb2_device.html
U-boot and Flash (NOR, NAND & SPI)
U-boot now has support for 3 different flash technologies:
NOR flash (traditional parallel 8-bit or 16-bit wide data bus, with a dedicated address bus).
NAND flash (newer technology 8-bit or 16-bit data bus, which is multiplexed with the address bus).
SPI serial flash (newer technology, simple 4-wire serial bus).
http://www.stlinux.com/u-boot/flash
NOR flash (traditional parallel 8-bit or 16-bit wide data bus, with a dedicated address bus).
NAND flash (newer technology 8-bit or 16-bit data bus, which is multiplexed with the address bus).
SPI serial flash (newer technology, simple 4-wire serial bus).
http://www.stlinux.com/u-boot/flash
2011年7月23日 星期六
2011年7月22日 星期五
2011年7月21日 星期四
2011年7月19日 星期二
2011年7月18日 星期一
2011年7月17日 星期日
2011年7月16日 星期六
2011年7月14日 星期四
2011年7月12日 星期二
Motorola Mobility launches wireless video bridge
http://www.iptv-news.com/iptv_news/april_2011/motorola_mobility_launches_wireless_video_bridge
CyWee Unveils 3 Products Integrating PC, Digital Home, Mobile Devices
http://www.prnewswire.com/news-releases/cywee-unveils-3-products-integrating-pc-digital-home-mobile-devices-80924322.html
2011年7月11日 星期一
2011年7月10日 星期日
2011年7月9日 星期六
2011年7月7日 星期四
2011年7月5日 星期二
台網通廠再現募資潮 60億資金陸續到位
台網通廠再現募資潮 60億資金陸續到位
台網通廠再現募資潮 60億資金陸續到位 2011/07/06-陳慧玲
台系網通設備廠包括啟碁、明泰、中磊、正文等，2011年上半陸續提出募資計畫，其中，中磊與正文6月底提出可轉債募資計畫，中磊預計以不超過6億元為額度發行可轉換公司債...
DIGITIMES中文網 原文網址: 台網通廠再現募資潮 60億資金陸續到位 http://www.digitimes.com.tw/tw/dt/n/shwnws.asp?CnlID=1&Cat=60&Cat1=10&id=0000240791_XFS8N3LQ8R5CTV21FSHO4#ixzz1RHBFbK00
台網通廠再現募資潮 60億資金陸續到位 2011/07/06-陳慧玲
台系網通設備廠包括啟碁、明泰、中磊、正文等，2011年上半陸續提出募資計畫，其中，中磊與正文6月底提出可轉債募資計畫，中磊預計以不超過6億元為額度發行可轉換公司債...
DIGITIMES中文網 原文網址: 台網通廠再現募資潮 60億資金陸續到位 http://www.digitimes.com.tw/tw/dt/n/shwnws.asp?CnlID=1&Cat=60&Cat1=10&id=0000240791_XFS8N3LQ8R5CTV21FSHO4#ixzz1RHBFbK00
2011年7月4日 星期一
TR-069
http://bawbaw-hu.blogspot.com/2007/03/tr-069.html
TR-069定義：
TR-069為 DSL Forum所定義的CPE WAN端的管理協定CPE WAN Management Protocol（CWMP），透過網路遠端管理客戶端設備的協定。
TR-069為Device和Auto Configuration Servers (ACS)之間共同的溝通方式，使用SOAP透過HTTP傳輸，包函了一個安全的自動設定和控制等管理的完整架構。ACS是一種裝置，可以管理終端設備、trouble shoot、設定、昇級等功能。
Protocol stack
TR-069的目的:
服務提供商(Service Providers)現在可以使用一個共同的管理平台,通過網路以使用TR-069的CPE及ACS完成廣大及覆雜的自動設定、管理所有客戶設備（像是modems, routers, gateways, Set-top box, paddles, VoIP-phones等等…）
TR-069 End-to-End Architecture
主要的功能:
自動設定及動態的服務更新。
軟體及韌體的管理。
狀態及效能的監控。
故障診斷。
TR-069相關延伸協定:
TR-098-Internet Gateway Device Data Model for TR-069(之前定義在TR-069的參數，現今全部移至TR-098)
TR-104-Provisioning Parameters for VoIP CPE(VoIP的參數)
TR-106-Data Model Template for TR-069 Enabled Devices
TR-110-Reference Models for VoIP Configurations in the DSL Home
TR-111-Remote. Management of Home Networking Devices
其餘WT階段文件不在此篇提出。
TR-069定義：
TR-069為 DSL Forum所定義的CPE WAN端的管理協定CPE WAN Management Protocol（CWMP），透過網路遠端管理客戶端設備的協定。
TR-069為Device和Auto Configuration Servers (ACS)之間共同的溝通方式，使用SOAP透過HTTP傳輸，包函了一個安全的自動設定和控制等管理的完整架構。ACS是一種裝置，可以管理終端設備、trouble shoot、設定、昇級等功能。
Protocol stack
TR-069的目的:
服務提供商(Service Providers)現在可以使用一個共同的管理平台,通過網路以使用TR-069的CPE及ACS完成廣大及覆雜的自動設定、管理所有客戶設備（像是modems, routers, gateways, Set-top box, paddles, VoIP-phones等等…）
TR-069 End-to-End Architecture
主要的功能:
自動設定及動態的服務更新。
軟體及韌體的管理。
狀態及效能的監控。
故障診斷。
TR-069相關延伸協定:
TR-098-Internet Gateway Device Data Model for TR-069(之前定義在TR-069的參數，現今全部移至TR-098)
TR-104-Provisioning Parameters for VoIP CPE(VoIP的參數)
TR-106-Data Model Template for TR-069 Enabled Devices
TR-110-Reference Models for VoIP Configurations in the DSL Home
TR-111-Remote. Management of Home Networking Devices
其餘WT階段文件不在此篇提出。
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