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From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Sockets for TSOP 64
References: <3D828A59.CDA3247C@webaccess.net> <3D82DA1F.2C249F96@webaccess.net> <firstname.lastname@example.org>
Date: Sat, 14 Sep 2002 14:29:35 GMT
NNTP-Posting-Date: Sat, 14 Sep 2002 07:29:35 PDT
Nico Coesel wrote:
> Chuck Simmons wrote:
> >Gary Tait wrote:
> >> On Sat, 14 Sep 2002 01:01:29 GMT, Chuck Simmons
> >> wrote:
> >> >I think the package is called TSOP 64. It has about 20 mil pin pitch and
> >> >the pins are on two sides of the package instead of all around. These
> >> >are flash parts and our programmer has a Yamaichi socket that releases
> >> >by pressing down (the pins are clamped from above by the contacts) and
> >> >our development board (which cannot do programming) has a Yamaichi clam
> >> >shell type socket (the pins are contacted from below).
> >> >
> >> >We have successfully used similar sockets to the first type with parts
> >> >having up to 100 pins and the second type works well for us in a 128 pin
> >> >model and a 208 pin model. We are not able to get reliable operation
> >> >with either socket for more than a minute or two with the flash parts.
> >> >That is, it can take 5 or 10 reseating attempts to get a part to program
> >> >and then we move it to the development board and it is hit or miss
> >> >whether the board will boot. The board itself is OK because it runs
> >> >perfectly from soldered down SRAM loaded through a JTAG interface.
> >> >
> >> >Unfortunately, it is not in our plan ever to solder down the flash on
> >> >the development boards (we theoretically can program flash through an
> >> >ATAPI interface but we don't have anyone to develop host side drivers to
> >> >do it). Thus we have to have removable flash in our lab and we have to
> >> >distribute preprogrammed flash parts to customers with development
> >> >boards even though they have JTAG load capability at some stations in
> >> >their labs.
> >> >
> >> Why not load the form Jtag?
> >1) I was one of the chip architects and I have very strong ideas about
> >how to develop with buried microprocessors in multiple chips. Important
> >is making development on one chip relatively independent of development
> >on the other. Flash loading is an important part of that.
> Do the boards have a serial port? Were I work we only put a small
> bootloader into the flash of a uC. This bootloader allows us to upload
> & start any piece of software into the board (either in flash or ram).
> I have a feeling that this method may be suitable for you as well.
> You could ommit the flash and mount a RAM chip on the evaluation board
> and have your evaluation customers upload software through the serial
The evaluation board has an SRAM that is a jumper option to the flash.
Our use of flash was to create a product development environment in
which various design functions could operate independently (mechanical,
optical, servo, host interface and so forth). That works as long as the
flash works. Our earlier rev boards use a PLCC flash which is reliable
in sockets but growth of the demonstration code forced us to a larger
flash only available in TSOP. We are too far along to back out of the
flash configuration. Anyway, the socket is a mechanical issue orthogonal
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons email@example.com
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