[Coco] 68764/68766 EPROMs

Al Hartman alhartman6 at optonline.net
Mon Sep 21 20:00:28 EDT 2015


Very cool!

My burners will handle 68766 EPROMS, but being able to use a 2764 will help 
lots of folks.

Thanks for doing this!

-[ Al ]-

-----Original Message----- 
From: Zippster

I just started drawing an adapter up a few minutes ago.
Cutting a deal for the proms to go with them.  They will be far less than 
$18.
I have quite a few CoCos that could use an ECB, so it’s something I’ve been
intending to do anyway.

I’ll should have files off to OSH Park tonight or tomorrow, there’s not much 
to an
adapter like this.

- Ed



> On Sep 21, 2015, at 5:53 PM, Al Hartman <alhartman6 at optonline.net> wrote:
>
> This is not for a disk controller. Ron needs an Extended BASIC ROM for a 
> Coco he bought. I no longer have any masked ROMs, and offered to burn him 
> one if he could get me the blank EPROMS.
>
> But a 2764 with an adapter will cost as much as that 68766 for $18.00, 
> unless Ron can wire one up himself.
>
> Clearance isn't a problem for an ECB ROM.
>
> -[ Al ]-
>
> -----Original Message----- From: Arthur Flexser
>
> P.S.  It is also possible to bypass the disk controller clearance problem
> by having a 28-pin 2764 or 27128 EPROM in a 24-pin disk controller socket
> with pins hanging off the end and other pins bent outward to not plug in,
> hand-wiring a few connections between things.  Not pretty, but workable.
>
> Art
>
> On Mon, Sep 21, 2015 at 6:33 PM, Arthur Flexser <flexser at fiu.edu> wrote:
>
>> There have been various such adapters in the CoCo and non-CoCo markets. 
>> I
>> sold one with ADOS for a time.  Cloud 9 sells a particularly low-profile
>> one, though it is somewhat more expensive than those sold by others. 
>> There
>> is not quite enough clearance for most adapters in the Tandy disk
>> controllers--some have tried cutting a hole in the plastic cover, or just
>> living with the cover not quite being able to snap shut (the screw will
>> keep the cover from coming off, and the controller can still be inserted 
>> in
>> the cartridge slot.  Probably not great for the long haul to have 
>> pressure
>> on the circuit board, though.)  The Disto controllers, with their sheet
>> metal covers, have a bit more clearance.  The problem of clearance is
>> greatly magnified if you want to piggyback a SmartWatch real-time clock
>> underneath the Disk Basic ROM.  (I went with a 
>> cutting-a-hole-in-the-cover
>> method there in my own CoCo system.)
>>
>> A consideration that also exists is that it may be harder to find an 
>> EPROM
>> programmer capable of programming the 6876x series than for the 27xx 
>> EPROMs.
>>
>> Art
>>
>>
>> On Mon, Sep 21, 2015 at 6:14 PM, Mark J. Blair <nf6x at nf6x.net> wrote:
>>
>>> Would it be more practical to make an adapter to plug in more common 
>>> 27xx
>>> series EPROMs? I don't recall how much physical clearance is in there.
>>>
>>> --
>>> Mark J. Blair, NF6X <nf6x at nf6x.net>
>>> http://www.nf6x.net/
>>>
>>>
>>> --
>>> Coco mailing list
>>> Coco at maltedmedia.com
>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>>
>>
>>
>
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