Quote:
Originally Posted by scotsman
Hi Kent... Now I can almost 100% assure you that when you plug in your new cable, nothing will happen. This is because a) I have once tried it with just bridging the pins with a needle...
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Shorting pins 4 & 5? In what way?
Quote:
Originally Posted by scotsman
... Somehow, when you plug in your PC, the DR detects it (when it asks you whether you wnt to mount)
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When a USB connection is made, the power pins (being longer) connect first. This causes the device that senses the power to poll the data lines (lines 2 & 3). If there is no signal, some devices, like the DR, assume that charge only is intended, and go to that mode. (Other devices shut down the port if there is no data; this is why
some--
adequately powered--chargers will not charge
some devices.)
Quote:
Originally Posted by scotsman
... and when you say yes, it seems to load some driver to operate the device in gadget (slave/device, not host) mode.
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I was hoping, if everything was wired as it
might be, that that OTG Host would be enabled at the hardware level, but that the Freescale, lacking drivers, would not know what to do, and throw up an error message. There are different ways for USB to be set up, but this would have been a sure fire way to know that we are not headed for a dead-end.
Quote:
Originally Posted by scotsman
One way to go were to find out which script is executed when mounting the device. I could try that on the emulator maybe, if the script is there, (on the emulator it is not such a pain to browse through directories and "cat" files then on the device - see my "terminal workaround" post).
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Back in 'the good old days' (the 70s) we used to be able to replace the processor's clock with a de-bounced switch, and
one-step through cycles; logic levels could be measured with a multi-meter at each 'cycle'--didn't really need a data analyzer or scope. Oh, the good old days. I don't envy you, scotsman, but
I wish I could help.
Quote:
Originally Posted by scotsman
On your open device, could you check where the usb is wired to? Are all pins connected to the freescale? It is clear that all pins are wired somewhere, since otherwise you could not charge the device and transfer data. The question, however, is wheter the power pins go to the freescale CPU as well, or to some charging circuit. This is important because we will need power out of the socket, which will only come from the CPU's USB controller.
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I will check, but tracing these circuits may not be as straightforward as you think. Also, as I have noted on another thread, when the battery is plugged in, the DR behaves the same as when a wall charger is plugged into the USB port. That
suggests that they
both go to the power management circuit.
For a mini B port, only pins 1,2,3 and 5 are used, those are all that are needed for power and data for a
non-Host connection. On the DR, all 5 pins
are wired on the circuit board, and this suggests that iRex designed for OTG;
there is no other reason to wire pin 4,
that is for Host. Note also that
any Data Out can trigger the USB power output--it depends how the designers chose to do it. It is choices like that, security-locked one-time-programmable (OTP) chips, and 'house marked' (i.e., unidentifiable) chips that complicate circuit tracing.
If iRex designed for OTG, one has to wonder why they
didn't implement it (it
might even have failed the USB OTG testing requirements). Considering also that iRex has not
fully implemented Host on
any device that I know of, my only guesses are not heartening for our effort.
Quote:
Originally Posted by scotsman
Also... once the right driver is in place, it should be possible to switch to host mode via software only.
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That
is part of the USB OTG Supplement, but it is an
optional implementation, and may not be available--
Oh, but it would be nice... If the DR's case weren't a
lock-box, the easiest thing would be to swap the mini B socket with a Mini AB--simple as pie--but it is what it is. Let us hope for the software option.
Thanks for the links and PDF, I'll go over it all and see if I can find anything useful before I start tracing circuits.
The last few days have been hectic... I just started a job that turned into a can of worms...
and took my Mom to the Hospital... I'll put what time I can into this.
Okay, I'm going shopping.
Kent