Re: [CAD_CAM_EDM_DRO] [EE]: USB stepper drive system

Dennis,

Have you looked at the Cypress AN21xx parts
(http://www.cypress.com/usb/datasheets.html) ?

One of the advantages of this chip is that the 8052 firmware is downloaded
by the Windows Device Driver. This makes microcode updates very easy.

I have not used the Cypress parts, however, I did do some work on the
original parts manufactured by AnchorChips. (Cypress purchased AnchorChips
about a year ago).

John

----- Original Message -----
From: Dennis Cranston <dennisc@...>
To: <CAD_CAM_EDM_DRO@...>
Sent: Wednesday, December 20, 2000 9:09 AM
Subject: RE: [CAD_CAM_EDM_DRO] [EE]: USB stepper drive system


> List
> I have been thinking in this same direction. Currently I have been trying
> to get my hands on a NetChip Net2890 Evaluation Board.
> http://www.netchip.com/products/2890eb.htm This board contains a USB
chip
> and a 8051 processor on the board. In addition, the board contains a
> parallel port. The kit is suppose to supply all source code for both the
> 8051 and the PC end.
> The theory is to have a distributed processing arrangement where the PC
> parses the Gcodes and develops step and direction commands along with some
> sort of a timing index. This 'packet' would be sent via USB to the board
> which would handle the timing and output through the parallel port to
motor
> control boards.
> At this point, I am still trying to get a $ response from the local
> distributer.
>
> Dennis
>
>
>
>
> On Tuesday, December 19, 2000 11:57 PM, Lawrence Glaister
> [SMTP:lg@...] wrote:
> >
> > There has been a lot of talk lately on the list promoting the
> development
> > of
> > some "smart hardware" to supplement the PC's poor performance. The
> second
> > item that is rearing its ugly head is that pc's are rapidly losing
their
> > ISA
> > slots and their serial/parallel ports. I also subscribe to the
usb-devel
> > list and am getting a pretty good feel for what usb is capable of. I
use
> > EMC
> > as the PC end smarts. It basically works well as an open source gcode
> > interpreter that expects to output a drive signal and receive back an
> > encoder signal for each axis every 1ms or so (programmable). The usb
bus
> > can
> > be thought of as a fast 12mb/sec serial port (about 1/2 of this is
> actually
> > usable). I am starting to think along the lines of a usb board that
> > contains
> > some number of rate generators (like Marriss's DDS system or even pic
> based
> > software DDS) to generate the stepper drive signals smoothly and the
> same
> > number of encoder interfaces (either in hardware counters or possibly
> pic
> > based software interfaces). The interface would use an isosyncronous
> read
> > port and a write port to read/write the command/status signals every
ms.
> A
> > four channel card would cover most applications although once design is
> a
> > little further along, it may be possible to put 6 axis on a card and
> > produce
> > them in various states of population. USB support is getting pretty
good
> > under linux, with quite a few example drivers. Between the lists, there
> is
> > a
> > lot of talent available... where to we need to be in a year from now?
> Would
> > USB make sense in a shop environment for getting machine control
> > information
> > in/out of the computer?
> > Would DAC outputs for servos make sense? Would +-50ma outputs make
sense
> > for
> > driving hydraulic servo valves? How much would the board cost to
> produce?
> > It
> > is going to be hard to beat the cost of an add-in parallel port. The
> card
> > would definitely make laptops or low end Macs like an iMac attractive
as
> a
> > dedicated controller. Just some ideas to think about for the next
> > generation
> > cnc controllers.
> > =======================================================
> > Lawrence Glaister VE7IT email: lg@...
> > 1462 Madrona Drive http://jfm.bc.ca
> > Nanoose Bay BC Canada
> > V9P 9C9
> > =======================================================
> >
> >
> >
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>
>
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