[coreboot] $7 cheap FT232H board as EHCI debug dongle for coreboot - would it work?

[Mike Banon]

These digikey cables do not explicitly mention that they have FT232H
chip, also they cost $23.5 minimum while aliexpress board costs $7 -
3x times less expensive

On Mon, Mar 5, 2018 at 7:06 PM, Vadim Bendebury <vbendeb at chromium.org> wrote:
> Did you consider one of these:
>
> https://www.digikey.com/products/en/cable-assemblies/smart-cables/468?k=ftdi+uart&k=&pkeyword=ftdi+uart&pv493=316&FV=ffe001d4&quantity=0&ColumnSort=0&page=1&pageSize=25
>
> there are many options, it is important to match the cable's VDD to your
> board's (1.8V vs 3.3V), the rest of the parameters is way less important.
>
> -vb
>
>
> On Sat, Mar 3, 2018 at 5:27 AM, Mike Banon <mikebdp2 at gmail.com> wrote:
>>
>> Good day! I am looking for the dirt cheap EHCI debug dongle. Initially
>> I found these instructions for FX2LP -
>> https://www.coreboot.org/DIY_EHCI_debug_dongle - but they require a
>> lot of manual soldering/mods which depend on your boards revision and
>> I am not sure if the currently produced boards are 100% compatible
>> with the wiki instructions
>>
>> But then I noticed a coreboot has USBDEBUG_DONGLE_FTDI_FT232H option:
>> " Use this with FT232H usb-to-uart. Configuration is hard-coded to use
>> 8n1, no flow control "
>>
>> Kyösti Mälkki tested it " with gizmosphere/gizmo1 Explorer add-on
>> board, which exposes the following device:
>>    0x0403 Future Technology Devices International, Ltd
>>    0x6014 FT232H Single HS USB-UART/FIFO IC "
>> but gizmo1 is expensive and I am not a fan of the single board
>> computers (SBCs) : they all require the binary blobs which could
>> contain the scary backdoors
>>
>> However, there are $7 cheap FT232H boards with USB available at
>> AliExpress:
>>
>>
>> https://www.aliexpress.com/item/NEW-CJMCU-FT232H-Multifunction-High-Speed-USB-to-JTAG-UART-FIFO-SPI-I2C-Module/32818305310.html
>>
>> I plan to get a couple of these boards, connect them to each other
>> with 1P 2.54mm wires, plug the 1st board into master PC
>> (coreboot-PC-under-debug) USB 2.0 port and the 2nd board into slave PC
>> (another coreboot PC which will be logging the debug info)
>>
>> Please tell me: could this setup work in theory, or there are obvious
>> shortcomings that could prevent it from working?
>>
>> Best regards,
>> Mike Banon
>>
>> --
>> coreboot mailing list: coreboot at coreboot.org
>> https://mail.coreboot.org/mailman/listinfo/coreboot
>
>