Author Topic: Think about USB Host  (Read 3773 times)

Offline Manish

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Think about USB Host
« on: August 25, 2012, 02:35:34 PM »
Hi Mark,

  Manish here, From last 2 year, we use Utasker RTOS for LPC2378/LPC2388. Now we would like to add some new device to our product,like USB. I seen your forum and document regarding that you have given support to USB slave as massstorage device or CDC. I have a USB host non RTOS source for lpc2388, so can you implement from that host in LPC23xx RTOS code?.

 From one step, I seen that many USB device(Bluethooth,Zigbee dongle,many Filed Digital Field sensor,GSM modem) work as CDC means we can read like a RS232. for those we need to use those device we add driver file in to PC, so in place of PC we expand those driver file and add in to our source  so we can communicate those USB CDC device if we add usb host for CDC device.  If you have like this. I think we can do it.

Manish Dabhi

Offline mark

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Re: Think about USB Host
« Reply #1 on: August 26, 2012, 09:26:05 PM »
Hi Manish

The uTasker project presently (still) doesn't include USB host support.

It is true that there are many dongles available for PCs (they are quite cheap) which extend them with various interfaces. Theoretically it is a very interesting approach to use USB host mode together with these dongles.

There may however be two risks involved:
- the PC dongles tend to be changed often and so are not so suitable for industrial use where long supply of such parts is usually important
- I think that you may find that the dongles are kept cheap by offloading a lot of the work (eg. the protocol stacks that their interfaces require) to the PC. That means that the 'clever' stuff is often in the PC driver and so to use them in embedded projects may require a lot of additional development since the interface will be quite low level and the stack, security, encryption etc. nned to be done in the processor. Embedded extension interfaces with integrated stack, allowing a simple application interface (without needing to do additional processing or solving the protocol details), are much easier to develop, avoid additional certification (for some interfaces) and also don't load the processor with these jobs.