Re: USB Breakout

On Feb 15, 2:24 pm, Mark Borgerson <mborger...@xxxxxxxxxxx> wrote:
In article <d9c3e27a-b3ee-4b69-9dcd-da12751e99d8>, cbarn24...@xxxxxxx says...

On Feb 13, 5:30ï¿=3Fpm, "}{" <snoozegr...@xxxxxxxxxxxxxxxx> wrote:
I am planning a project and would appreciate any guidance you guys could

At the moment, I have a measurement device connected to a decoder box - the
decoder box is connected to another PCB using a USB cable.

If practical, I would like to break into the USB cable running between the
decoder box and the PCB to modify the values on the fly. Specifically, if
two digits(say char 5 and char 6) are the same, a 1 would be appended,
otherwise a 0 would be appended.

So if 123456789 were transmitted from the decoder, I would like to intercept
and change it to 1234567890.

Likewise if 123455789 were transmitted, I would change this to 1234557891
and send on.

I have some experience programming PICs and RS232 but no experience using
USB(2 in this case).

Initially, I was thinking about using a PIC with a USB input connected to
the decoder, the same connected to the PCB and SPI between the two PICs.

Firstly, is this possible, and do you have any pointers on PICs & USB2..


Cant you use a usb to rs232 converter, pic, rs232 to usb converter.
You can get them ready made or just use the chips.

The USB part of the RS232 converter has to connect to a PC or other
host device that can handle all the enumeration and
control signals. IIRC, the device described by the OP,
has only one host and one slave device---not the two hosts
your converters would require.

For the sake of arguing, you can use a usb device to rs232 converter
(ftdi), pic and rs232 to usb host converter (avr).

Mark Borgerson