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High speed USB chip?

A

Ancient_Hacker

Jan 1, 1970
0
Let's say I have a flash A/D putting out a byte every 100nsec or so.

Is there some simple chip that will take this data and send it to a
PC thru a USB-2 port?

hoping... Hoping.....
 
L

linnix

Jan 1, 1970
0
Let's say I have a flash A/D putting out a byte every 100nsec or so.

Is there some simple chip that will take this data and send it to a
PC thru a USB-2 port?

hoping... Hoping.....

Very difficult to get 80 Mb/s through USB.
 
J

Jim Thompson

Jan 1, 1970
0
Very difficult to get 80 Mb/s through USB.

Ehhh?

"Hi-Speed USB mode is capable of ... 480Mbits/second."

...Jim Thompson
 
L

linnix

Jan 1, 1970
0
Ehhh?

"Hi-Speed USB mode is capable of ... 480Mbits/second."

But chopped into 64 byte chunks and host enabled signalings.
A missed timing can delay the communications by msecs.
You need very good host hardware and firmware control on the PC side.

In theory, you can send 50 mpeg streams over usb (480/9).
I have not seen too many device with more than 1 stream.
 
J

Joel Kolstad

Jan 1, 1970
0
linnix said:
But chopped into 64 byte chunks and host enabled signalings.
A missed timing can delay the communications by msecs.
You need very good host hardware and firmware control on the PC side.

Well, it's true, you can't use crap USB chipsets and lousy drives, but the
GNURadio guys routinely sustain ~256Mbps over USB with decent quality hardware
and software; I believe I've heard them say that realistically the USB 2.0
limit is around ~320Mbps (40MBps).

80Mbps should be no problem.

Granted, I wouldn't stick this data acquisition device on the same bus as the
one you have a web cam, audio device, mouse, keyboard, etc. on -- I'd give it
a USB controller of its very own.
 
D

Donald

Jan 1, 1970
0
Jim said:
Ehhh?

"Hi-Speed USB mode is capable of ... 480Mbits/second."

480M(bits)/sec / 8 bits per byte = 60M(bytes)/sec

without any overhead.

It would be easier with a TCP connection.
...Jim Thompson


donald
 
L

linnix

Jan 1, 1970
0
Well, it's true, you can't use crap USB chipsets and lousy drives, but the
GNURadio guys routinely sustain ~256Mbps over USB with decent quality hardware
and software; I believe I've heard them say that realistically the USB 2.0
limit is around ~320Mbps (40MBps).

80Mbps should be no problem.

Granted, I wouldn't stick this data acquisition device on the same bus as the
one you have a web cam, audio device, mouse, keyboard, etc. on -- I'd give it
a USB controller of its very own.

Or crapy window drivers. I hate to disappoint the CEO of Seagate,
but I can't watch smooth porn on my super-fast usb hard drive.
So, the effective rate is probably less than 9 Mb/s.

480 Mb/s usb is like saying:
Vista is fine with less than 1G ram.
 
R

Robert Lacoste

Jan 1, 1970
0
Ancient_Hacker said:
Let's say I have a flash A/D putting out a byte every 100nsec or so.

Is there some simple chip that will take this data and send it to a
PC thru a USB-2 port?

hoping... Hoping.....

Cypress has some high speed USB enabled microcoontrollers that allows a data
stream to be directly routed to the USB engine, see for example the EZUSB
FX2LP (CY7C68014A ), data throughput is claimed to be 53Mbyte/s, which
should be ok for your application.

Cheers,
 
H

Hawker

Jan 1, 1970
0
We are using the Cypress FX2 series parts, as someone else mentioned,
for several projects.
The FIFOs are a bit small so we often have to use an external FIFO.
For my current project I have one bolted to CPLD and external SRAM for a
sorta FIFO.

Note for USB2 the theoretical maximum is 480M BITS/Sec. So that is 60M
Bytes per sec. In reality 80% is about all you can do or around
50mBytes per sec (Cypress claims a bit better though). Your project is 8
x (100nS^-1) or 80mBytes per sec. Not doable sustained, Perhaps cached
locally and sent later?

Hawker
 
R

Roger Hamlett

Jan 1, 1970
0
Hawker said:
We are using the Cypress FX2 series parts, as someone else mentioned,
for several projects.
The FIFOs are a bit small so we often have to use an external FIFO.
For my current project I have one bolted to CPLD and external SRAM for a
sorta FIFO.

Note for USB2 the theoretical maximum is 480M BITS/Sec. So that is 60M
Bytes per sec. In reality 80% is about all you can do or around
50mBytes per sec (Cypress claims a bit better though). Your project is 8
x (100nS^-1) or 80mBytes per sec. Not doable sustained, Perhaps cached
locally and sent later?

Hawker
Er. You are out by a factor of eight. He is pulling one byte every
100nSec.
Total just 10MB/sec.
Perfectly doable.

Best Wishes
 
J

Joel Kolstad

Jan 1, 1970
0
Hawker said:
Your project is 8 x (100nS^-1) or 80mBytes per sec.

Umm... shouldn't that be 80Mbits per second? He wanted to sample one bytes
every 100nS = 10 million samples/sec = 10Mbytes/sec = 80Mbps?
 
R

Roger Hamlett

Jan 1, 1970
0
Hawker said:
Yes as Roger and you pointed out I goofed.
That is what I get for only half paying attention to what I am doing.
100nS-1 = 10M/bytes *8 = 80mBits per second.
So this will fit no problem I blew it.

Hawker
The second question though is using 'm', not 'M'. Normally 'b' is bits,
'B' is bytes, 'm' is milli, and 'M' is mega. If he only wanted 80mBits, it
could be done using RS232 serial!...
The stupid thing is just how easy this type of slip is. I sent a post
myself to 'Hawker', and managed to generate the right answer, but type
'mSec', instead of 'nSec'....
It is a big danger of using the 'prefix' letters.

Best Wishes
 
H

Hawker

Jan 1, 1970
0
Yes as Roger and you pointed out I goofed.
That is what I get for only half paying attention to what I am doing.
100nS-1 = 10M/bytes *8 = 80mBits per second.
So this will fit no problem I blew it.

Hawker
 
J

joseph2k

Jan 1, 1970
0
Robert said:
Cypress has some high speed USB enabled microcoontrollers that allows a
data stream to be directly routed to the USB engine, see for example the
EZUSB FX2LP (CY7C68014A ), data throughput is claimed to be 53Mbyte/s,
which should be ok for your application.

Cheers,
Only on a dedicated single device USB controller. Protocol overhead and
protocol timing limitations matter.
 
M

Mike Harrison

Jan 1, 1970
0
Only on a dedicated single device USB controller. Protocol overhead and
protocol timing limitations matter.

These guys :
https://www.quickusb.com/index.htm?target=dept_13.html
do a module based on the Cypress chip which comes with driver software to make USB2 comms fairly
painless.
However you might need to add a fifo between the ADC and the USB interface to guarantee no data
loss.
 
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