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kster59
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Post by kster59 »

My understanding of the 3318 is that it is a PHY only.

You need to write all the drivers BOTH on the PC side AND on the XMOS side.

This involves a LOT of work.

To put it in context, that USB audio driver company charges $8000 for a license to use their driver unrestricted.

Also to put it in context that XTAG2 has a 3318 and XMOS still hasn't released a working VCP driver for it let alone a bulk transfer protocol which makes it useless for basically all my projects (can't even debug printf statements).

It appears a lot of people seem to develop board designs before even trying it out on a dev board.


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wibauxl
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Post by wibauxl »

Agreed for the board development!
The issue with the 3318 is that with SMC, you have to develop a mini-board to host it before you can test...

For the driver, if you go for a mass storage or a HID, you don't have to develop them, as they are embedded in the OS. I was planning to have the board appear as a disk with a firmware folder if the BL was activated and whatever the user wanted (HID or mass storage) when BL is inactive. This would make the firmare update quite easy. A bit naive perhaps...

Going for the FT232 greatly simplifies the development of the BL firmware but also makes need for a software side for the firmware uploader.
Last edited by wibauxl on Tue Jun 29, 2010 4:56 pm, edited 1 time in total.
kster59
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Post by kster59 »

I've written a USB firmware loader using the FT245R that works well. Libflash makes it pretty easy.

Having a USB folder seems interesting but that seems really easy to delete the firmware.

To implement HID or mass storage you can choose other usb solutions besides FTDI. My plan was to implement and sell a low cost module based on an C8051F321 which I already laid out. The Silabs chip has an internal oscillator and power supply which makes it very nice to use as a single optional chip solution (can leave it out with no effects). It also has an HID mouse demo (not sure about mass storage) and USBXpress (easy to use USB).

Maybe I will still go ahead eventually but previously I had some discount with XMOS chips and they told me I couldn't use it for production so felt a bit screwed that I did the development a week before this announcement and right now the project is just for internal use.

I encourage use of the silabs chip with connection through SPI which I used as a USB AND ADC request line and can help a little with it.
JohnR
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Post by JohnR »

Hi,
I encourage use of the silabs chip with connection through SPI which I used as a USB AND ADC request line and can help a little with it.
I would second the use of these Silabs USB chips. I recently used them to implement a USB to 4-20mA link, feeding 4 converters via SPI. It is very easy to use, at least in the HID mode, which allows a surprising amount of flexibility in sending/receiving data. The Silabs publications and forums are also very helpful.

John
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wibauxl
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Post by wibauxl »

kster59 wrote:Having a USB folder seems interesting but that seems really easy to delete the firmware.
The idea is not to show the factory image, nor the original image.
The device would appear as a small empty drive when the bootloader is selected.
To restore original behaviour, the user will erase all files on the drive.
He can add firmware.xxx.bin where xxx is the image number.
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wibauxl
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Post by wibauxl »

kster59 wrote:I've written a USB firmware loader using the FT245R that works well.
Better go for a FT245R or FT232R?
Of course, there is a big difference in pin count used (and routing...), but can you benefit from the increased bandwidth of the FT245 in VCP mode?
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