There is a trend observed in the market for designing products with SuperSpeed USB and NAND Flash inside. There are camera manufacturers, printer manufacturers as well as FLASH drive manufacturers involved in the trend. It is crucial, at this point of time in the market, to have a proper knowhow on what factors affect such designs and what can be done to achieve a successful and a longlife design.
The USB 3.0 standard claims that it is 10 times faster than USB 2.0. The theoretical speed is 4.8Gbps (600MBps). However looking at various realistic speed test reports made available by more
than one developers, it has been concluded that 400MBps is the maximum achievable speed for this standard.
Factors affecting performance
Depending on the NAND Flash used in the system, the performance can be estimated. But, there are a number of factors affecting the speed and performance of USB in a system. Eric Huang has listed
the dependencies very interestingly in his blog. I am listing them here.
The USB transfer speed is affected by the following factors:
Looking into a nonidealized system, the SLS SuperSpeed USB Device IP Core tests performed on GigaByte A75 Motherboard have indicated the performance ~2.1Gigabits per second (262.5
Megabytes per second) with mass storage interface and ~2.7Gigabits per second (337.5 Megabytes per second) with raw interface.
There is a word in the development community about NAND Flash being the bottleneck for USB performance.
Lets see how the performance numbers with the NAND Flash look like. Mass storage performance tests with SLS SuperSpeed IP and ONFI controller IP (without ECC overload) have indicated speed
upto 101.5 MBps (812 Mbps).
What does this mean?
Not bad to have this solution for the current product upgrade...
For more information on the numbers, you can contact email@example.com or visit www.slscorp.com/ip-cores
Here is a short video that explains the procedure for booting VxWorks OS on Stratix III Dev. Kit using MP32 IP core.
The video does not have audio instructions. We are in the process of updating the video with audio instructions.
Coming soon: video with audio instructions.
More Information at: http://www.slscorp.com/pages/mp32.php
The title should not be a surprise here in the USB Community since SuperSpeed USB is now in the market. Still this is a news for developers working on this.
Talking about SuperSpeed USB, the USB 3.0 standard claims that it is 10 times faster than USB 2.0. The theoretical speed is 4.8Gbps (600MBps). However looking at various realistic speed test reports made available by more than one developers, it has been concluded that 3.2 Gbps (400MBps) is the maximum achievable speed for this standard.
The core efficiency is dependent on a number of factors like 8b/10b encoding, packet structure and framing, link level flow control and protocol overhead.
Various tests performed with SLS SuperSpeed USB core indicate the speed of 400MB/s in an embedded system.
At 5Gbps signalling rate with 8b/10b encoding, the raw throughput is 500MBps. When link flow control, packet framing, and protocol overhead are considered, it is realistic for 400MBps or more to be delivered to an application.
What speed can I have in my new product with SuperSpeed interface?
If you have this question in your mind, you are at the right place. One of our clients evaluating the USB 3.0 core practically achieved the speed of 2.5Gbps for IN operation and 2Gbps for OUT operation.
The raw throughput of 500MBps can be observed on the USB 3.0 Development Board (between FPGA and PHY). The picture below shows the board:
2Gbps speed is achieved on this board using SLS USB 3.0 Device core. The block diagram of the core is given below: