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Date:   Thu, 21 Nov 1996 15:53:04 +1000
From: Mick Gulovsen   bigmik@blaze.net.au
Subject: Minor errors with SS

Hi there,

Maybe this has already been looked at (I am not sure as I have been a
bit out of touch for the last few weeks) but here goes:

I just got around to putting my FED'57 basic SS together and discovered
the following,

1.  On Antti's overlay the pullup for the SCL pin (pin 6) of the EEPROM
is omitted. there is a place for this at the 2 pads shown between the
EEPROM and the 57 chip.

of course the Cheap comms (all components to left of ic4) is NOT reqd if
you use Dons mother board.

2.  The position of the brownout CCT on pic.002 is not shown, it can be
placed where the triangle of pads are under r2 (R2 is NOT required if
the brownout is used), the correct orientation for the brownout ic (dons
version anyway) is with the flat towards the '57.

3.  With the brownout ic installed dons m/b WONT reset the pic, it is
reqd to place a link across the 330 ohm resistor on the PCB (labelled
r14 on PCB itself see next note)

4.  On Dons m/b the overlay shows the current limiting R as R14 for the
reset button whereas the CCT diagram shows it to be R15 (which is really
the BOOT switches one).


Q.  Is the output of this brownout chip Open collector ? Is it safe to
directly short it out? Maybe a better solution is to put the 330 ohm
between the output of the chip and the reset of the SS.
===============================================================
Subject: Re: Minor errors with SS

Antti's response:

>1.  On Antti's overlay the pullup for the SCL pin (pin 6) of the EEPROM
>is omitted. there is a place for this at the 2 pads shown between the
>EEPROM and the 57 chip.

Mick This: SCL PULL-UP Is not required for I2C operation and it seems
FED Basic is happy without it too!

>of course the Cheap comms (all components to left of ic4) is NOT reqd if
>you use Dons mother board.

sure

>2.  The position of the brownout CCT on pic.002 is not shown, it can be
>placed where the triangle of pads are under r2 (R2 is NOT required if
>the brownout is used), the correct orientation for the brownout ic (dons
>version anyway) is with the flat towards the '57.

Thanks, I hope it was drawn correctly, but dont have any to test with:(

>3.  With the brownout ic installed dons m/b WONT reset the pic, it is
>reqd to place a link across the 330 ohm resistor on the PCB (labelled
>r14 on PCB itself see next note)
>
>4.  On Dons m/b the overlay shows the current limiting R as R14 for the
>reset button whereas the CCT diagram shows it to be R15 (which is really
>the BOOT switches one).
>
>
>Q.  Is the output of this brownout chip Open collector ? Is it safe to
>directly short it out? Maybe a better solution is to put the 330 ohm
>between the output of the chip and the reset of the SS.

It depends on the type of bo used. I think most are open collector,
what brings us to PIC.002 major bug, if open-collector brownout is on
board and board is used "stand-alone" then there is really no place for
reset pullup, except to mount a SMD res directly on brownout pins.

=======================================================================

Don's response: 22-Nov-96
OK on the shorting of the resistor Mick. I'll check the component labels
too, and correct the circuit and instructions.

The BO chips I have are CMOS output, not open collector, so they don't
require a resistor, however the open collector may be required if the reset
is to be daisy-chained, or reset to ground.
Perhaps both types may be required.

=======================================================================

>Date:   Fri, 22 Nov 1996 15:17:59 +1000
From: Mick Gulovsen  bigmik@blaze.net.au
Subject: Re: Minor errors with SS

Hi there Antti (and Co),

> Mick This: SCL PULL-UP Is not required for I2C operation and it seems
> FED Basic is happy without it too!

Ok! No worries then. It is supported on the PCB anyway but fine if its
not needed then there is no need to use it
 
> >2.  The position of the brownout CCT on pic.002 is not shown, it can be
> >placed where the triangle of pads are under r2 (R2 is NOT required if
> >the brownout is used), the correct orientation for the brownout ic (dons
> >version anyway) is with the flat towards the '57.
> 
> Thanks, I hope it was drawn correctly, but dont have any to test with:(

Yes! it appears to be drawn correctly.
I didnt check the ceap comms as I have an aversion to using it, I prefer
max myself.

> >3.  With the brownout ic installed dons m/b WONT reset the pic, it is
> >reqd to place a link across the 330 ohm reseistor on the PCB (labelled
> >r14 on PCB itself see next note)

This may because Don bought the CMOS version of the panasonic resets. I
would think the OPEN DRAIN version would work ok... Another point here
with open collector/drain shouldnt there be a pull-up resistor on the
MCLR?

> >Q.  Is the output of this brownout chip Open collector ? Is it safe to
> >directly short it out? Maybe a better solution is to put the 330 ohm
> >between the output of the chip and the reset of the SS.
> 
> It depends on the type of bo used. I think most are open collector,
> what brings us to PIC.002 major bug, if open-collector brownout is on
> board and board is used "stand-alone" then there is really no place for
> reset pullup, except to mount a SMD res directlry on brownout pins.

Aha answered my question before I asked it.  Pretty good service I'd
say.  =8-)

> Mick, please let me know what you are doing with it! If it is anything
> useful what you are ready to share lets start making app-notes!

Thats fine, I dont mind sharing, in fact I encourage it. I have to admit
that on a personal level (at THIS moment) I am only interested in using
the FED basic SS. As I am usually using an LCD I use the 57 version,
however when the 74 version is available I will be using that one. I
will then buy the FED basic compiler and do away with the EEPROM.
===============================================================
From - Sat Nov 23 05:47:24 1996
From: Mick Gulovsen    bigmik@blaze.net.au
Subject: Re: Minor errors with SS

Gday Fellas,

> The BO chips I have are CMOS output, not open collector, so they don't
> require a resistor, however the open collector may be required if the reset
> is to be daisy-chained, or reset to ground.

Of course you can always but a 1k ohm R between the output of the CMOS
b.o. an easy place to do this is to cut the track on the back of the
pic.002 PCB that goes from the output of the b.o. to the small via and
place the R in there on the back.

> Perhaps both types may be required.

Perhaps.

CYAs
======================================================================
Subject: Re: Minor errors with SS
Date: Fri, 22 Nov 1996 04:37:36 +0200 (sat)
From: Kalle Pihlajasaari   kalle@device.data.co.za

Hi All,

> http://www.labyrinth.net.au/~donmck/ss-users.html
> has been added to my sstudio page.

I must have a look here.

> Have attached a quick response that I put there too.
> 
> I just wonder if SimmStick User list server is just about in order now.

Action at last :-)  I can set up a list if Antti is not about to
get one from his ISP right away.  We can move the user base over
later is we like (I'm getting good at renaming mailing lists ;-}


> Ben, do you have data on digikey BO ccts. I think mabey we need CMOS OP
> and Open Collector OP depending on function. PIC.002 may need CMOS
> anyway as it requires a resistor otherwise. And there isn't room. :(

I am much agains the CMOS output Reset ICs.  They are less versetile and 
the next rev of the board can certainly have place for the pull up
so I am going to stick with an extra resistor, under the board if need be.

> After board-room talks with Mick (Friday night drink session on Thursday
> night), I may drop my cheap programmer in favour of the DT001 board. It
> will push users into the direction we all want to go. May also adjust
> price down a little if I do this.

Sounds great, I have had 2 nibbles on the DT001 and the SS concept here
and have just done the first draft of my new iprice list found at

  http://www.ip.co.za/ip/catalog.htm

> OK on the shorting of the resistor Mick. I'll check the component labels
> too, and correct the circuit and instructions.
> 
> The BO chips I have are CMOS output, not open collector, so they don't
> require a resistor, however the open collector may be required if the reset
> is to be daisy-chained, or reset to ground.
> Perhaps both types may be required.

Lets all stick with the OC reset chips, they can be used in so many more
ways.

Cheers
-- 
Kalle Pihlajasaari     kalle@ip.co.za
Interface Products     P O Box 15775, DOORNFONTEIN, 2028, South Africa
+ 27 (11) 402-7750     Fax: 402-7751
===============================================================