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jecottrell
Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ
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Bootloader through a FTDI USB/Serial Interface? |
Posted: Thu Dec 07, 2006 1:18 pm |
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Hello All,
I was wondering if anyone has implemented a 'typical' serial type bootloader (tinybld, CCS, Microchip, etc.) through a FTDI USB interface?
It would be nice to be able to bootload via USB with an off-the-shelf bootloader. At the moment I'm trying to decide whether to move to USB or stick with serial.
Any comments, suggestions, experience, or wisdom would be appreciated.
Thanks,
John |
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Ttelmah Guest
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Posted: Thu Dec 07, 2006 3:41 pm |
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There is nothing much to this. The FTDI chips/modules, are the core of many of the USB-serial converter cables on the market. A far as the PIC is concerened, it only sees normal serial (with the advantage of not needing a MAX232, since the chips give 'logic level' serial, with the right polarity to directlyinterface to the PIC's UART. As far as the PC end is concerened, this is just seen as a USB serial port, and functions exactly like any other serial port.
I have half a dozen different things that use these modules, and a couple implement bootloaders. In one case, the FTDI chip is optional, and can be replaced by a RS232 connector and interface chip. As far as the code at both ends is concerned behaviour is identical whichever interface is used.
If you want to go 'custom', FTDI, will supply small blocks of USB addresses, and using these (and reprogramming the ROM on the interface), allows the unit to be seen with a custom 'name', and if required to hide it's simple serial nature.
Best Wishes |
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jecottrell
Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ
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Posted: Thu Dec 07, 2006 4:45 pm |
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RJ,
Thanks. That's what I was hoping and had cautiously assumed. I think I'll give it a go.
John |
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jma_1
Joined: 08 Feb 2005 Posts: 147 Location: Wisconsin
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Posted: Thu Dec 07, 2006 5:15 pm |
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Greetings,
Ttelmah is correct.
I'm presently using an FTDI chip in a project and have not had any issues. On a side note, try to pick one of the newer chips by FTDI or Silicon Labs. Some of the newer chips have built in EEPROM and might not need a separate oscillator. The new Vinculum chip by FTDI can even by a USB host or slave.
Cheers,
JMA |
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Martin Berriman
Joined: 08 Dec 2005 Posts: 66 Location: UK
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Posted: Sat Dec 09, 2006 10:27 am |
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jma_1 wrote: | Some of the newer chips have built in EEPROM and might not need a separate oscillator. The new Vinculum chip by FTDI can even by a USB host or slave. |
The latest FT232R does indeed not require an external crystal, EEPROM or USB impedance matching resistors - well worth changing over to.
I am currently experimenting with a Vinculum device. Idea is to have the PIC check the USB flash disk for a certain file at boot up and if found then perform a firmware upgrade. This is quite a lot to stuff into a bootloader though so needs one of the bigger devices... |
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ratgod
Joined: 27 Jan 2006 Posts: 69 Location: Manchester, England
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Posted: Tue Dec 12, 2006 10:48 am |
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@martin
many thanks for this tidbit, im going to to switch over completely on my next project |
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