USB interface on MSP430

[Srihari Marni]

Hi,

i am interested in developing a system that will send and receive data  from the computer to a micro-controller( MSP430)  through USB .

MSP430 has  USART, and only 256 bytes of ram and 8Kb of flash.

do you know if  256 bytes of ram is enough?

Plz help.

[Kartik Mohta]

You would of course need a USB-serial interface for this. The amount
of RAM needed depends on the application. How much data do you need to
send/receive per transfer?

--
Kartik

[Srihari Marni]

i need to send about 4kb of flash memory.. i want to know if  USB 2.0 protocol can be implemented on this chip.

thank you kartik.

[Kartik Mohta]

I don't think you can have proper USB2.0 on the MSP, you should be
able to get a USB low-speed implementation on it though. There is an
AVR implementation available here:
http://www.obdev.at/products/vusb/index.html, you can probably port
the code over to the MSP.

Can you elaborate more on what you are planning to do?

--
Kartik

[Srihari Marni]

Actually all I need is to send the data collected by MSP430 ( from other devices previously)  to a laptop. I wonder if usual laptop usb port can support the low speed implementation you have mentioned. do you mean usb1.1 implementation? I  want to know if this MSP 430 can interact with latest USB port on a laptop or pc...
thanks again.

[Srihari Marni]

i dont have any necessity on speedy connection, if it works thats more than enough. after all the data i would be sending is as low as 4KB.

[Kartik Mohta]

That site says that the implementation is USB 1.1 compatible and USB
2.0 hosts are supposed to be backwards compatible with USB 1.0/1.1, so
that should work with any new laptop/PC. The main challenge would be
porting the code from the AVR to the MSP.

--
Kartik

[Srihari Marni]

also i really doubt if 256 bytes of ram would be enough. if it can be implemented i can sit and write my own code from scratch but i am in the process of deciding Microcontroller for my application, i already ordered Launchpad for this MSP430 microcontroller.
Hope it works. Thanks a lot.

[Siraj Issani]

If the highlight of your project is not porting of usb stack on a uC, then why not use a virtual serial port over usb in laptop for data commit? You can use the existing usart and transmit data with as high as 38.4kBaud/s. You can use any COTS usb serial port hardware.

--
Siraj

On 30 Apr 2011 00:53, "Srihari Marni" <rok...@gmail.com> wrote:

[Ashish Goel]

I think the simplest way of doing this would be to use an FTDI chip for serial to USB conversion. I have an MSP 430 communicating with the USB port of an SBC through the FTDI chip on my desk right now.

PS: I am an alumnus not in IIT anymore.

[Siraj Issani]

On 30 Apr 2011 01:49, "Ashish Goel" <ashi...@stanford.edu> wrote:
>
> I think the simplest way of doing this would be to use an FTDI chip for serial to USB conversion. I have an MSP 430 communicating with the USB port of an SBC through the FTDI chip on my desk right now.
>
> PS: I am an alumnus not in IIT anymore.

And his desk is probably sunlit at this very moment :P

[Srihari Marni]

Hi Siraj,

Thanks for your idea, looks good. but from productivity point of view  circuit cost increases.

regards
Srihari

[Ashish Goel]

Not really. My lab is in the basement :)

http://www.phdcomics.com/comics/archive.php?comicid=872

[Kartik Mohta]

On Fri, Apr 29, 2011 at 4:23 PM, Srihari Marni <rok...@gmail.com> wrote:
> Hi Siraj,
>
> Thanks for your idea, looks good. but from productivity point of view
> circuit cost increases.
>

From a productivity point of view, you save a lot of time by using the
USB-serial converter :)

--
Kartik

[Srihari Marni]

Thank you Karthik and Ashish.

Ashish, Can you tell me which chip it is?? I mean ID and some more details.

Thank you

[Siraj Issani]

I guess you meant the product BOM cost increases. That is very true. This also rules out a FTDI chip based circuit solution as it is costlier on both time and money.
Productivity-wise a COTS component should actually save time.

--
Siraj

On 30 Apr 2011 01:53, "Srihari Marni" <rok...@gmail.com> wrote:

[Mehul Tikekar]

Why don't you just use an AVR instead of MSP430. The VUSB site that Mohta mentions probably has the project already done for you :)

Mehul

[Ashish Goel]

What I have is FT232RL

[Srihari Marni]

Mehul, looks thats a convenient way, but i have ordered a Launchpad already for MSP430
anyways i will try coding and see... i dont think it would be difficult.
if its not doable i will go ahead with AVR chip.

[Srihari Marni]

Thank you Ashish and Sriaj.

[Siraj Issani]

On 30 Apr 2011 02:08, "Ashish Goel" <ashi...@stanford.edu> wrote:
>
> What I have is FT232RL

To reduce costs you can look at ftdi chips from vinculum.

[Srihari Marni]

http://e2e.ti.com/support/microcontrollers/msp43016-bit_ultra-low_power_mcus/f/166/t/92172.aspx

looks like i need VNC2

[Kartik Mohta]

I don't think you need USB Host functionality, yours would just be a
USB peripheral.

--
Kartik

[Srihari Marni]

karthik, usb host in sense powering device.., r8. ok

[Siraj Issani]

On 30 Apr 2011 02:15, "Kartik Mohta" <karti...@gmail.com> wrote:
>
> I don't think you need USB Host functionality, yours would just be a
> USB peripheral.

Ditto. For the record, vnc1l is good enough for host functionality. But I would seriously discourage designing a circuitry around a usb controller chip for this application unless you need the design experience. I would strongly recommend a commercially off-the-shelf circuit module or a usb serial port.

[Srihari Marni]

I would strongly recommend a commercially off-the-shelf circuit module or a usb serial port.

hmm., but why do u think we cant do a low speed USB connection with direct MSP itself

[Srihari Marni]

Also can any body elaborate diff between host and peripheral.. except powering up?

[Siraj Issani]

On 30 Apr 2011 02:32, "Srihari Marni" <rok...@gmail.com> wrote:
>
>
>
> I would strongly recommend a commercially off-the-shelf circuit module or a usb serial port.
>
> hmm., but why do u think we cant do a low speed USB connection with direct MSP itself

No, thats not what I think. What I said was only in the interest of time.

[Srihari Marni]

Hi Siraj,

I am looking for few open source regarding the same, looks like code is not so tough to implement.. I even found some guy who did it on MSP430, getting in touch with him for the code .. :-)