[Coco] Grant Searles SBC

[Kip Koon]

Hi Matthew,
I played around with several capacitance values on my breadboard version 4 years ago and never did decide on which one to use.  I'll try it on my Kipper SBC as I forgot to put one on the reset line as well as the breadboard.  That maybe one of the reasons why I didn't get an output on the serial port at the CoCoFEST.  Thank you for the suggestion.  I had forgotten about that.  You are the man!  :)

Kip Koon
computerdoc at sc.rr.com
http://www.cocopedia.com/wiki/index.php/Kip_Koon


> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Matthew Stock
> Sent: Wednesday, May 06, 2015 7:32 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: Re: [Coco] Grant Searles SBC
> 
> Bill,
> 
> When it's in this state, what do BA and BS look like on rise of Q?  are they both high?  If not, it's not a halt state but something else.
> Only thing I can think of is to put a 1uF cap between the reset line and ground to complete the RC circuit and see if that helps.  I
> suspect the reset isn't a clean slope and that's annoying the CPU.
> 
> Matt
> 
> 
> On Wed, May 6, 2015 at 7:16 PM, Bill Nobel <b_nobel at hotmail.com> wrote:
> 
> > Hi guys.  This is a shout out to the Hardware Experts out there.  I am
> > trying to build this unit on a breadboard and am having some issues.
> > I am following the circuit to a tee.  Powering up I get 1.843 mhz on
> > the E & Q lines R/W is working.  But sometimes when I hit reset my BA
> > line goes high throwing CPU into HALT state even though my HALT is
> > tied High.  Also on the terminal window I am getting nothing but
> > garbage @ 115200 baud.  The one difference to the circuit I am using a
> > FTDI instead of the 9 pin serial plug.  I verified the FTDI by
> > connecting to a old desktop pc using Hyperterm so the chip is working.
> > But on the SBC I get nothing.  I even went to the extent of swapping
> > out all the chips and verified by hand the Eprom code to see if it Burned properly.
> >
> >  Any suggestions or help would be appreciated.
> >
> > Bill Nobel
> >
> >
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