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RE: [N8VEM: 0] Re: PropIO improvements
Hi Dave! Thanks! I am going to defer the reworking the PCB layout until we
do a larger redesign of the PropIO. By keeping the existing layout I can
avoid the lengthy PCB respin and reorder the PCBs this weekend.
Thanks and have a nice day!
Andrew Lynch
> -----Original Message-----
> From: n8...@googlegroups.com [mailto:n8...@googlegroups.com] On Behalf Of
> yoda
> Sent: Wednesday, July 07, 2010 11:41 PM
> To: N8VEM
> Subject: [N8VEM: 0] Re: PropIO improvements
>
> Hi Andrew,
>
> That sounds like a good idea and we can experiment with the second
> prop on the current board and prove that the 2 propeller idea works.
> I guess we can just cut the traces on the second propeller and jumper
> them up to the proto area.
>
> On the jumpers for P30 and P31 make sure they are cross over jumpers
> ie propeller 1 P30 -> propeller 2 P31 and propeller 1 P31 ->
> propeller 2 P30.
>
> BTW with a little different layout (rotate props 90 degrees and mount
> resistors vertically) would give a bigger proto area I think
>
> On Jul 7, 9:28 pm, "Andrew Lynch" <lyn...@yahoo.com> wrote:
> > Hi Dave! At this point, I've got three fixes in the board.
> >
> > 1. the VGA mount holes
> > 2. removed P13 interProp line
> > 3. fixed transistor footprints.
> >
> > I can easily add additional jumpers to allow P30 and P31 to interlink
> the
> > Propellers and that is no problem.
> >
> > At this point though I am thinking just do these minor clean ups and
> tweak
> > and just let the rest be as it is while the software catches up. As it
> > matures and the SBC V2 comes out then for the next round of PropIO
> boards
> > start looking into these advanced features.
> >
> > I am also thinking more like what Max was saying. The builders may be
> > better served by splitting the PropIO into a "stable" board with VGA,
> PS/2
> > keyboard, uSD, Ethernet, and USB host on a board. Then make a new
> > "developer" PropIO board with two Propellers with one dedicated to the
> ECB
> > and the other completely unassigned for experimentation purposes except
> for
> > the inter-Prop link. Then get rid of the expansion mezzanine concept
> since
> > the "developer" PropIO would have a lot of free space for builder
> expansion.
> >
> > Actually we could start on the second board pretty soon to hash out the
> > development concepts since it would be basically a stripped down PropIO.
> >
> > The big advantage is that I can send the existing PropIO basically "as
> is"
> > with minor changes to PCB manufacturing in the next weekend without
> major
> > redesign cycle. Then I can catch up on these other projects floating
> about.
> >
> > How does that sound for a plan? Thanks and have a nice day!
> >
> > Andrew Lynch
> >
> > > -----Original Message-----
> > > From: n8...@googlegroups.com [mailto:n8...@googlegroups.com] On Behalf
> Of
> > > yoda
> > > Sent: Wednesday, July 07, 2010 9:34 PM
> > > To: N8VEM
> > > Subject: [N8VEM: 7444] Re: PropIO improvements
> >
> > > Hi Andrew,
> >
> > > Let me try to answer some of the questions.
> >
> > > What I meant by SPI is there are a lot of devices that talk SPI that
> > > we can hang off of the propeller as there is a good low level driver
> > > for SPI which is used to actually communicate with the uSD now so we
> > > could reuse that code.
> >
> > > On freeing up one of the address lines, I want to hold off on that for
> > > the moment - I was actually wanting to use it for further addressing.
> > > For the high speed communications port we still have available P30 and
> > > P31 which are only used to load the initial programs into the
> > > propeller's eeprom. We can implement a set of jumpers that you remove
> > > to program and then insert them when you are operational. Ray
> > > (cluso99) did the same thing on the triblade prop which worked very
> > > well. My fear if we go to a command and data port that the loop for
> > > parsing the commands is going to get very long and that has to be in
> > > PASM and would not be easy for the uninitiated to try to write code
> > > for. I am also thinking in the new scheme we might want to rearrange
> > > some of the I/O so that some of it is on the second propeller (I have
> > > to check but I think we are out of cogs on propeller 1 and we will
> > > need to free at least one cog for inter prop communication)
> >
> > > Yes I think that object will work but I think there is actually a
> > > better one around that is even faster and implements a command
> > > protocol which we will want.
> >
> > > I don't think losing a separately addressable propeller is a bad thing
> > > because in fact it will be addressable by sending command strings via
> > > the first propeller (just a different communications path and probably
> > > as fast)
> >
> > > Dave
> >
> > > On Jul 7, 7:31 pm, "Andrew Lynch" <lyn...@yahoo.com> wrote:
> > > > Thanks Dave! OK, I think I understand what you are saying and
> propose a
> > > new
> > > > course of action.
> >
> > > > First, I fixed the problem with the PCB footprints for the PNP
> > > transistors
> > > > Q1 and Q3. They were reversed and now fixed.
> >
> > > > > -----Original Message-----
> > > > > From: n8...@googlegroups.com [mailto:n8...@googlegroups.com] On
> Behalf
> > > Of
> > > > > yoda
> > > > > Sent: Tuesday, July 06, 2010 9:31 PM
> > > > > To: N8VEM
> > > > > Subject: [N8VEM: 7423] Re: PropIO improvements
> >
> > > > > Hi Andrew,
> >
> > > > > Sounds interesting. I would wait a little on the decision as
> there is
> > > > > work on a different chip that has a full tcp/ip stack built in and
> > > > > around the same price or cheaper. It uses the same type of
> interface
> > > > > and will be much simpler to program in the long run. Also I have
> a
> >
> > > > [AJL>]
> >
> > > > OK, scratch the Ethernet mod and I'll just leave the existing
> > > functionality.
> > > > If builders want this functionality they can build a prototype and
> once
> > > > demonstrated working I'll include it in a future Propeller ECB
> board.
> >
> > > > > couple of the sparkfun usb break out boards that use SPI as well.
> I
> > > > > think it would be interesting adding serial ports with a much
> smaller
> > > > > footprint. I think there are all kinds of opportunities here. I
> > > > > think we might want to be able to jumper one more address line in
> > > > > where P13 is. There are so many things we can hang off the
> propeller
> > > > > that have SPI ports that can be useful we may run out of
> addressable
> >
> > > > [AJL>]
> > > > SPI serial ports? Do you mean SPI ports or serial ports driven by
> SPI?
> > > Do
> > > > you have a link for an example?
> >
> > > > > ports to the propeller. I guess the other thing is to have a
> command
> > > > > port that selects what the data port(s) do. It will be tricky to
> code
> > > > > but I have been pretty successful in the PASM code to make things
> > > > > happen. I was surprised with the uSD port I was still faster than
> the
> > > > > propeller could handle and had to insert the waitpeq into the
> stream
> > > > > to wait on the chip select line.
> >
> > > > [AJL>]
> >
> > > > I think this is very important. We should switch to a command port
> and
> > > data
> > > > port interface. Then we would only require A0 to distinguish
> between
> > > the
> > > > command and data port. That would free up P15 which we could use
> with
> > > P13
> > > > to form a high speed interPropeller communications link.
> >
> > > > Once we have a working interPropeller communications link then
> dedicate
> > > the
> > > > first Propeller to full time ECB bus interface. The first Propeller
> > > uses
> > > > several pins to communicate with the ECB and another two to
> communicate
> > > with
> > > > the second Propeller. It also handles the VGA, PS/2 keyboard, and
> the
> > > uSD
> > > > interface. The second Propeller's IO pins would be mostly free for
> > > > additional IO devices rather than spending 11 pins duplicating an
> > > interface
> > > > with the ECB.
> >
> > > > What we lose is separately addressable Propellers but gain a lot of
> IO
> > > pins
> > > > and also a high speed interPropeller communications link. The good
> news
> > > > about this approach is that it is mostly compatible with the
> existing
> > > PropIO
> > > > board. We can jumper the pins between the Propellers for the
> > > interPropeller
> > > > communications link. Then cut the traces on the second Propeller to
> > > free
> > > > them up from the ECB interface.
> >
> > > > Here is an example of fast inter-Propeller link. I gather it uses
> only
> > > a
> > > > single pin each way but we may want to use a diode between the
> > > Propellers to
> > > > protect the transmitter from a HIGH-LOW mismatch and also dedicate
> >
> > > >http://obex.parallax.com/objects/546/
> >
> > > > Probably there are many ways to implement so this is just an
> example.
> >
> > > > > One suggestion might be is run a small batch with the current
> fixes
> > > > > and let some of us play with some ideas on the second port before
> > > > > doing a larger run. I have not even populated the second chip yet
> so
> > > > > I don't know if there are any problems there, though I would
> expect
> > > > > not as it is such a simple interface.
> >
> > > > [AJL>]
> >
> > > > Yes, this is certainly possible and even easy to do. I can export
> the
> > > freed
> > > > up pins to a dual row header for expansion to the prototyping area
> > > and/or
> > > > mezzanine.
> >
> > > > > Just some ideas - I am on vacation at end of this week for a few
> days
> > > > > - when I get back will finish up some of the current code - found
> a
> > > > > few bugs in the terminal driver that I want to fix and then I will
> > > > > start playing with the second prop and finalizing a driver for
> CP/M 3
> > > > > that will support two 512 MB drives (I have figured out how I want
> to
> > > > > do the protocol for it - should only require less than 10 lines of
> > > > > spin code change)
> >
> > > > > Dave
> >
> > > > [snip]
> > > > [AJL>] That's great! Enjoy your vacation and I look forward to your
> > > return!
> > > > Thanks and have a nice day!
> >
> > > > Andrew Lynch
> >
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