Hi All
Just a word of warning to anyone developing USB on the Olimex LPC2478-STK.
There are two circuit diagrams on the Olimex web site:
- http://www.olimex.com/dev/images/ARM/LPC/LPC2478-STK-sch.gif
and
- http://www.olimex.com/dev/pdf/ARM/LPC/LPC-2478STK.pdf (the user's manual
with a circuit diagram embedded in it)
The first shows the USB device connector connected to U2D+/U2D- and USB host to
U1D+/U1D-.
The second shows the USB device connector connected to U1D+/U1D- and USB host to
U2D+/U2D-.
Logically the device would be connected to U2 since this allows the host to run
at the same time on U1 (the inversion is not true).
The Rev. A board (the one that I have and the one shown in the user's
manual) has the USB device connected to U1D+/U1D-. Of course I was working with
the first circuit diagram and - because things just didn't want to work -
ended up tracing the tracks on the board, which resulted in the discovery of the
cross-over and ultimately the second diagram...
What is also strange is that the USB_CONNECT and VBUS signals are not actually
connected to USB_CONNECT or VBUS pins on the LPC2478 - even though the signals
are names as one would expect. This means that these signals need to be be
controlled via GPIOs instead.
Looking at the IAR USB code reference (I believe that the IAR board is an IAR
badged Olimex board) it happily controls the USB_CONNECT pin, so I wonder how it
manages to work...:-0
Regards
Mark
http://www.uTasker.com
Olimex LPC-2478-STK USB
Started by ●April 16, 2010
Reply by ●April 17, 20102010-04-17
Hi Mark,
This topic was discussed on the problem, too.
http://tech.groups.yahoo.com/group/lpc2000/message/45569
Tsuneo
--- In l..., "Mark" wrote:
>
> Hi All
>
> Just a word of warning to anyone developing USB on the Olimex LPC2478-STK.
>
> There are two circuit diagrams on the Olimex web site:
> - http://www.olimex.com/dev/images/ARM/LPC/LPC2478-STK-sch.gif
> and
> - http://www.olimex.com/dev/pdf/ARM/LPC/LPC-2478STK.pdf (the user's manual with a circuit diagram embedded in it)
>
> The first shows the USB device connector connected to U2D+/U2D- and USB host to U1D+/U1D-.
> The second shows the USB device connector connected to U1D+/U1D- and USB host to U2D+/U2D-.
>
> Logically the device would be connected to U2 since this allows the host to run at the same time on U1 (the inversion is not true).
>
> The Rev. A board (the one that I have and the one shown in the user's manual) has the USB device connected to U1D+/U1D-. Of course I was working with the first circuit diagram and - because things just didn't want to work - ended up tracing the tracks on the board, which resulted in the discovery of the cross-over and ultimately the second diagram...
>
> What is also strange is that the USB_CONNECT and VBUS signals are not actually connected to USB_CONNECT or VBUS pins on the LPC2478 - even though the signals are names as one would expect. This means that these signals need to be be controlled via GPIOs instead.
>
> Looking at the IAR USB code reference (I believe that the IAR board is an IAR badged Olimex board) it happily controls the USB_CONNECT pin, so I wonder how it manages to work...:-0
>
> Regards
>
> Mark
> http://www.uTasker.com
>
This topic was discussed on the problem, too.
http://tech.groups.yahoo.com/group/lpc2000/message/45569
Tsuneo
--- In l..., "Mark" wrote:
>
> Hi All
>
> Just a word of warning to anyone developing USB on the Olimex LPC2478-STK.
>
> There are two circuit diagrams on the Olimex web site:
> - http://www.olimex.com/dev/images/ARM/LPC/LPC2478-STK-sch.gif
> and
> - http://www.olimex.com/dev/pdf/ARM/LPC/LPC-2478STK.pdf (the user's manual with a circuit diagram embedded in it)
>
> The first shows the USB device connector connected to U2D+/U2D- and USB host to U1D+/U1D-.
> The second shows the USB device connector connected to U1D+/U1D- and USB host to U2D+/U2D-.
>
> Logically the device would be connected to U2 since this allows the host to run at the same time on U1 (the inversion is not true).
>
> The Rev. A board (the one that I have and the one shown in the user's manual) has the USB device connected to U1D+/U1D-. Of course I was working with the first circuit diagram and - because things just didn't want to work - ended up tracing the tracks on the board, which resulted in the discovery of the cross-over and ultimately the second diagram...
>
> What is also strange is that the USB_CONNECT and VBUS signals are not actually connected to USB_CONNECT or VBUS pins on the LPC2478 - even though the signals are names as one would expect. This means that these signals need to be be controlled via GPIOs instead.
>
> Looking at the IAR USB code reference (I believe that the IAR board is an IAR badged Olimex board) it happily controls the USB_CONNECT pin, so I wonder how it manages to work...:-0
>
> Regards
>
> Mark
> http://www.uTasker.com
>
Reply by ●April 17, 20102010-04-17
Hi Tsuneo
Thanks, that seems to tie up.
Strange thing is that I did a search for "LPC2478" - there were 355 threads which I checked through - only 2 of them were to do with USB but a different USB topic.
The one that you link to doesn't turn up, although it has LPC2478 in its subject - therefore I never found it before....
Regards
Mark
--- In l..., "t_chinzei" wrote:
>
> Hi Mark,
>
> This topic was discussed on the problem, too.
> http://tech.groups.yahoo.com/group/lpc2000/message/45569
>
> Tsuneo
Thanks, that seems to tie up.
Strange thing is that I did a search for "LPC2478" - there were 355 threads which I checked through - only 2 of them were to do with USB but a different USB topic.
The one that you link to doesn't turn up, although it has LPC2478 in its subject - therefore I never found it before....
Regards
Mark
--- In l..., "t_chinzei" wrote:
>
> Hi Mark,
>
> This topic was discussed on the problem, too.
> http://tech.groups.yahoo.com/group/lpc2000/message/45569
>
> Tsuneo
Reply by ●April 17, 20102010-04-17
Hi
As follow up I tried searching for the thread. Using advanced search I enter "LPC2478" in the subject and get 199 matches. Still this thread is not listed.
Then I tried with the search word "Olimex". This gave me 435 hits but again not including this thread.
After a little investigation I realised that the newest thread that I was getting (in both cases) was from around the 20th March 2009 (anything newer doesn't show)
How did you manage to find it again? Is this a general search problem or is it restricted to me???
Regards
Mark
--- In l..., "Mark" wrote:
>
> Hi Tsuneo
>
> Thanks, that seems to tie up.
>
> Strange thing is that I did a search for "LPC2478" - there were 355 threads which I checked through - only 2 of them were to do with USB but a different USB topic.
>
> The one that you link to doesn't turn up, although it has LPC2478 in its subject - therefore I never found it before....
>
> Regards
>
> Mark
>
> --- In l..., "t_chinzei" wrote:
> >
> > Hi Mark,
> >
> > This topic was discussed on the problem, too.
> > http://tech.groups.yahoo.com/group/lpc2000/message/45569
> >
> > Tsuneo
>
As follow up I tried searching for the thread. Using advanced search I enter "LPC2478" in the subject and get 199 matches. Still this thread is not listed.
Then I tried with the search word "Olimex". This gave me 435 hits but again not including this thread.
After a little investigation I realised that the newest thread that I was getting (in both cases) was from around the 20th March 2009 (anything newer doesn't show)
How did you manage to find it again? Is this a general search problem or is it restricted to me???
Regards
Mark
--- In l..., "Mark" wrote:
>
> Hi Tsuneo
>
> Thanks, that seems to tie up.
>
> Strange thing is that I did a search for "LPC2478" - there were 355 threads which I checked through - only 2 of them were to do with USB but a different USB topic.
>
> The one that you link to doesn't turn up, although it has LPC2478 in its subject - therefore I never found it before....
>
> Regards
>
> Mark
>
> --- In l..., "t_chinzei" wrote:
> >
> > Hi Mark,
> >
> > This topic was discussed on the problem, too.
> > http://tech.groups.yahoo.com/group/lpc2000/message/45569
> >
> > Tsuneo
>
Reply by ●April 17, 20102010-04-17
--- In l..., "Mark" wrote:
> How did you manage to find it again? Is this a general search problem or is it restricted to me???
>
> Regards
>
> Mark
>
The search feature for the Yahoo Groups is seriously broken. It used to work pretty well a couple of years ago. Lately, not so much.
Richard
> How did you manage to find it again? Is this a general search problem or is it restricted to me???
>
> Regards
>
> Mark
>
The search feature for the Yahoo Groups is seriously broken. It used to work pretty well a couple of years ago. Lately, not so much.
Richard
Reply by ●April 17, 20102010-04-17
On 17/04/2010 15:08, rtstofer wrote:
> --- In l..., "Mark" wrote:
>
>> How did you manage to find it again? Is this a general search problem or is it restricted to me???
>>
>> Regards
>>
>> Mark
>> The search feature for the Yahoo Groups is seriously broken. It used to work pretty well a couple of years ago. Lately, not so much.
The group is archived here:
http://www.embeddedrelated.com/groups.php
A search of the archive might work a lot better.
Leon
--
Leon Heller
G1HSM
> --- In l..., "Mark" wrote:
>
>> How did you manage to find it again? Is this a general search problem or is it restricted to me???
>>
>> Regards
>>
>> Mark
>> The search feature for the Yahoo Groups is seriously broken. It used to work pretty well a couple of years ago. Lately, not so much.
The group is archived here:
http://www.embeddedrelated.com/groups.php
A search of the archive might work a lot better.
Leon
--
Leon Heller
G1HSM
Reply by ●April 17, 20102010-04-17
Hi Leon
Yes, that works well!!!
Many thanks - this will certainly help in the future.
Regards
Mark
--- In l..., Leon Heller wrote:
>
> On 17/04/2010 15:08, rtstofer wrote:
> >
> >
> > --- In l..., "Mark" wrote:
> >
> >> How did you manage to find it again? Is this a general search problem or is it restricted to me???
> >>
> >> Regards
> >>
> >> Mark
> >>
> >
> > The search feature for the Yahoo Groups is seriously broken. It used to work pretty well a couple of years ago. Lately, not so much.
>
> The group is archived here:
>
> http://www.embeddedrelated.com/groups.php
>
> A search of the archive might work a lot better.
>
> Leon
> --
> Leon Heller
> G1HSM
>
Yes, that works well!!!
Many thanks - this will certainly help in the future.
Regards
Mark
--- In l..., Leon Heller wrote:
>
> On 17/04/2010 15:08, rtstofer wrote:
> >
> >
> > --- In l..., "Mark" wrote:
> >
> >> How did you manage to find it again? Is this a general search problem or is it restricted to me???
> >>
> >> Regards
> >>
> >> Mark
> >>
> >
> > The search feature for the Yahoo Groups is seriously broken. It used to work pretty well a couple of years ago. Lately, not so much.
>
> The group is archived here:
>
> http://www.embeddedrelated.com/groups.php
>
> A search of the archive might work a lot better.
>
> Leon
> --
> Leon Heller
> G1HSM
>
