Topics

CDP1802 "Kit"

 

  FYI - The CPU is the only hard to find part, but the asking price is less than many people pay for the 1802 chip alone.

 

               https://www.bgmicro.com/9z1510.aspx

 

I have no connection with BG Micro, although I have ordered from them a few times and have always been happy.

 

Bob

 

 

P.S.  Just realized that it's missing any kind of address latch chip (e.g. a 74HC373) which you would need to build any working system with these parts.  BG may not realize that it's required.  Hardly a big deal, but worth mentioning.

 

  Oooppsss - I guess this is old news.   Sorry!

ajparent1/kb1gmx
 

Last i checked thye did miss the latch not they do sell them.

Minor thing as the ram and erprom are such that a updated circuit would be needed
as the uninitiated likely have no clue.

Lee Hart
 

ajparent1/kb1gmx wrote:
Last i checked thye did miss the latch not they do sell them.

Minor thing as the ram and erprom are such that a updated circuit would
be needed
as the uninitiated likely have no clue.
I did send them an email outlining this, with links to working Elf schematics etc. No reply yet (though I rarely expect one from a company).

Not only is the latch missing, but also something for an address decoder. Then it will need some kind of I/O to do anything useful.

The simplest circuit I can think of would add a 4042 4-bit latch with both true and inverted outputs. Clock it with TPA to latch A8, A9, A10, and A15. Use the true and inverted outputs of A15 to select ROM at 0, RAM at 8000h. With only A0-A10 available, you could use 2K of the EPROM, and 2K of the RAM.

Burn RCA's UT4 or my IDIOT monitor into the EPROM. Use Q and EF4 for TTL serial I/O.

Lee Hart

--
ICEs have the same problem as lightbulbs. Why innovate and make
better ones when the current ones burn out often enough to keep
you in business? -- Hunter Cressall
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

 

Would there be any problems latching all eight upper address bits by adding a single '373 or '573 and selecting ROM with A15 on /CE (pin 18) and selecting RAM with A15 on active high E2 (pin 26) with active low /E1 (pin 20) grounded?  You'd have eight 4K ROM images spanning $0000..$7FFF and four 8K RAM images spanning $8000..$FFFF.

Happy Holidays.  Mike


From: "Lee Hart" <leeahart@...>
To: cosmacelf@groups.io
Sent: Wednesday, December 18, 2019 5:51:25 PM
Subject: Re: [cosmacelf] CDP1802 "Kit"

ajparent1/kb1gmx wrote:
> Last i checked thye did miss the latch not they do sell them.
>
> Minor thing as the ram and erprom are such that a updated circuit would
> be needed
> as the uninitiated likely have no clue.

I did send them an email outlining this, with links to working Elf
schematics etc. No reply yet (though I rarely expect one from a company).

Not only is the latch missing, but also something for an address
decoder. Then it will need some kind of I/O to do anything useful.

The simplest circuit I can think of would add a 4042 4-bit latch with
both true and inverted outputs. Clock it with TPA to latch A8, A9, A10,
and A15. Use the true and inverted outputs of A15 to select ROM at 0,
RAM at 8000h. With only A0-A10 available, you could use 2K of the EPROM,
and 2K of the RAM.

Burn RCA's UT4 or my IDIOT monitor into the EPROM. Use Q and EF4 for TTL
serial I/O.

Lee Hart

--
ICEs have the same problem as lightbulbs. Why innovate and make
better ones when the current ones burn out often enough to keep
you in business? -- Hunter Cressall
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com




ajparent1/kb1gmx
 

Mike,
That works but only if further expansion is not needed.
No one says you must fully decode addresses.

 

It's just an alternative to Lee's "simplest circuit I can think of" which provides at least the same, probably more, capability compared to the 4042 suggestion.  Of course you still need to add I/O.

Why do you think the suggested circuit would hinder expansion?  Layout your board with a 32-pin RAM socket and plug in the 8K RAM or a 64K RAM and the same decoding scheme (active lo A15 = ROM, active hi A15 = RAM) will map 32K of RAM into the address space at $8000..$FFFF with the 64K RAM chip installed.  64K and 128K RAM chips are relatively inexpensive.  You can do something similar to expand the ROM.  

Mike


From: "ajparent1/kb1gmx" <kb1gmx@...>
To: cosmacelf@groups.io
Sent: Wednesday, December 18, 2019 10:11:36 PM
Subject: Re: [cosmacelf] CDP1802 "Kit"

Mike,
That works but only if further expansion is not needed.
No one says you must fully decode addresses.

Lee Hart
 

Mike McLaren, K8LH wrote:
Would there be any problems latching all eight upper address bits by
adding a single '373 or '573 and selecting ROM with A15 on /CE (pin 18)
and selecting RAM with A15 on active high E2 (pin 26) with active low
/E1 (pin 20) grounded? You'd have eight 4K ROM images spanning
$0000..$7FFF and four 8K RAM images spanning $8000..$FFFF.
I didn't look up the specs for that 8K RAM. If it has an active-high chip select, your scheme should work! It provides more memory than my minimal scheme. :-)

If you're going to make a board, you might as well lay it out with jumper options to also support up to a 32k EPROM, and 128k RAM. There are 128k RAMs that also have an active-high chip select pin. You could only use 32k of that RAM, but you'd have a 4-chip system with 64k of memory and a bit-banger serial port.

Lee

--
ICEs have the same problem as lightbulbs. Why innovate and make
better ones when the current ones burn out often enough to keep
you in business? -- Hunter Cressall
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

 

Perhaps something like this (attached) for RAM expansion (128K RAM chips are cheap) and then do something similar for the ROM (EEPROM)?  Still need some I/O...



From: "Lee Hart" <leeahart@...>
To: cosmacelf@groups.io
Sent: Wednesday, December 18, 2019 11:22:17 PM
Subject: Re: [cosmacelf] CDP1802 "Kit"

Mike McLaren, K8LH wrote:
> Would there be any problems latching all eight upper address bits by
> adding a single '373 or '573 and selecting ROM with A15 on /CE (pin 18)
> and selecting RAM with A15 on active high E2 (pin 26) with active low
> /E1 (pin 20) grounded?  You'd have eight 4K ROM images spanning
> $0000..$7FFF and four 8K RAM images spanning $8000..$FFFF.

I didn't look up the specs for that 8K RAM. If it has an active-high
chip select, your scheme should work! It provides more memory than my
minimal scheme. :-)

If you're going to make a board, you might as well lay it out with
jumper options to also support up to a 32k EPROM, and 128k RAM. There
are 128k RAMs that also have an active-high chip select pin. You could
only use 32k of that RAM, but you'd have a 4-chip system with 64k of
memory and a bit-banger serial port.

Lee

--
ICEs have the same problem as lightbulbs. Why innovate and make
better ones when the current ones burn out often enough to keep
you in business? -- Hunter Cressall
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com




 

... selecting ROM with A15 on /CE (pin 18) and selecting RAM with A15 on active high E2
  That's what I had in mind.  As for I/O, you could use one of those TTL level USB to serial adapters and connect it directly to Q and some EFx pin.  With the sole addition of the address latch, you should have enough here to run Tiny BASIC.
 

Lee Hart
 

Bob Armstrong wrote:
... selecting ROM with A15 on /CE (pin 18) and selecting RAM with
A15 on active high E2
That's what I had in mind. As for I/O, you could use one of those
TTL level USB to serial adapters and connect it directly to Q and some
EFx pin. With the sole addition of the address latch, you should have
enough here to run Tiny BASIC.
Good point, Bob.

Here's a Christmas "card" for all you Elves. Order one of these 1802 kits from BGMicro, and I'll provide an 1802MC CPU board to use them for $8 (plus postage to wherever you live).

(Obviously, you don't need their kit, if you already have the parts in your junk box.)

If you have an EPROM programmer for the 2732 they supply, I have the code for Tiny BASIC and the IDIOT monitor on my website. Program this into the EPROM, and you're in business!

If you don't have a programmer, I can supply a programmed EPROM for another $2.

There are a few other small parts you'll need; a few resistors and capacitors, a 74HC373 address latch, etc. You can also add a few more chips to provide an input and output ports.

Merry Christmas!
Lee Hart

--
Obsolete (Ob-so-LETE). Adjective. 1. Something that is simple,
reliable, straightforward, readily available, easy to use, and
affordable. 2. Not what the salesman wants you to buy.
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

 

Slightly off-topic but I was thinkin'...  Wouldn't it be nice to take advantage of the extra memory on those 128K RAM chips.  An 'untested' concept for mapping 16K banks in and out of the 64K address space is attached.

Cheerful regards, Mike


From: "Bob Armstrong" <bob@...>
To: cosmacelf@groups.io
Sent: Thursday, December 19, 2019 10:33:55 AM
Subject: Re: [cosmacelf] CDP1802 "Kit"

... selecting ROM with A15 on /CE (pin 18) and selecting RAM with A15 on active high E2
  That's what I had in mind.  As for I/O, you could use one of those TTL level USB to serial adapters and connect it directly to Q and some EFx pin.  With the sole addition of the address latch, you should have enough here to run Tiny BASIC.
 

Lee Hart
 

Lee Hart wrote:

Here's a Christmas "card" for all you Elves. Order one of these 1802
kits from BGMicro, and I'll provide an 1802MC CPU board to use them
for $8 (plus postage to wherever you live).
...
There are a few other small parts you'll need; a few resistors and
capacitors, a 74HC373 address latch, etc. You can also add a few more
chips to provide an input and output ports.

Merry Christmas!
Lee Hart
Thanks for the orders! This will keep Santa's elves busy. :-)

Some additions to my hastily-posted offer:

1. Send orders directly to me at <leeahart@...> to avoid clutter on the cosmacelf list.

2. I didn't notice that the BGMicro #9Z1510 kit comes with a 0.6" wide RAM chip (MCM6064P12). The 1802MC PCB is set up for a 0.6" wide EPROM (like the 2732) and a 0.3" wide RAM (like the CY7C199).

BGMicro has a Toshiba TC5588P-20 0.3" wide 8K RAM (their #ICSTC5588P) for $1.39. I haven't tried it yet, but it should drop right in to the 1802MC board. Either order one with your kit, or ask if they can substitute it for the MCM6064P12.

3. If you've already ordered your BGMicro kit, I can provide the CY7C199 32k RAM for $2 each. Bonus; it increases your RAM to 32k. :-)

4. Both Tiny BASIC and the IDIOT monitor fit in one 4K EPROM.

5. Or, if you're getting the EPROM from me, I can also provide a 32k EPROM with Chuck Yakym's MCSMP20 monitor and BASIC3 for the same price $2).

I'll put some Paypal "buy now" buttons on my web page at <www.sunrise-ev.com/1802.htm to make these options easier to order. Look for them tomorrow!

Happy ho-ho-holidays!
Lee Hart


--
Obsolete (Ob-so-LETE). Adjective. 1. Something that is simple,
reliable, straightforward, readily available, easy to use, and
affordable. 2. Not what the salesman wants you to buy.
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Lee Hart
 

Lee Hart wrote:
I'll put some Paypal "buy now" buttons on my web page at
<www.sunrise-ev.com/1802.htm> to make these options easier to order. Look
for them tomorrow!
OK; I made a couple new Paypal buttons at <http://www.sunrise-ev.com/1802.htm>. To keep from getting buried by too many options, I just provided two:

*SPECIAL #1* is $8.00 for just the 1802MC CPU board.

*SPECIAL #2* is $10.00 for the 1802MC CPU board, a 32K EPROM programmed with the MCSMP20 monitor and RCA's BASIC3, and a 32K RAM.

The EPROM and RAM supplied with the BGMicro kit will work in the 1802MC; but not at the same time. Download the manual on the same web page for details. :-)

Happy Holidays,
Lee Hart
--
Obsolete (Ob-so-LETE). Adjective. 1. Something that is simple,
reliable, straightforward, readily available, easy to use, and
affordable. 2. Not what the salesman wants you to buy.
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

Peter Renaud
 

Hi,
That’s a great deal! Where do I sign up? I already have the parts from my Cosmac Elf build and I have a programmer. I was thinking of also getting the BGmicro kit but shipping to Canada was more than half the cost.
Thanks


From: cosmacelf@groups.io <cosmacelf@groups.io> on behalf of Lee Hart <leeahart@...>
Sent: Friday, December 20, 2019 1:26:56 AM
To: cosmacelf@groups.io <cosmacelf@groups.io>
Subject: Re: [cosmacelf] CDP1802 "Kit"
 
Lee Hart wrote:
> I'll put some Paypal "buy now" buttons on my web page at
> <www.sunrise-ev.com/1802.htm> to make these options easier to order. Look
> for them tomorrow!

OK; I made a couple new Paypal buttons at
<http://www.sunrise-ev.com/1802.htm>. To keep from getting buried by too
many options, I just provided two:

*SPECIAL #1* is $8.00 for just the 1802MC CPU board.

*SPECIAL #2* is $10.00 for the 1802MC CPU board, a 32K EPROM programmed
with the MCSMP20 monitor and RCA's BASIC3, and a 32K RAM.

The EPROM and RAM supplied with the BGMicro kit will work in the 1802MC;
but not at the same time. Download the manual on the same web page for
details. :-)

Happy Holidays,
Lee Hart
--
Obsolete (Ob-so-LETE). Adjective. 1. Something that is simple,
reliable, straightforward, readily available, easy to use, and
affordable. 2. Not what the salesman wants you to buy.
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com



ajparent1/kb1gmx
 

Lee,

Order is in for two of the special 2. 

Allison

 

I believe BG Micro just bumped the price for the CDP1802ACE processor by two bucks and the kit by three bucks...  

ajparent1/kb1gmx
 

Yes they did.   I've not seen an invoice from them yet either.  The latter
is important as the order was pre price change.

David Schultz
 

On 12/22/19 10:15 AM, ajparent1/kb1gmx wrote:
Yes they did.   I've not seen an invoice from them yet either.  The latter
is important as the order was pre price change.

They have been running a sale (12 days of Christmas) and that was the
sale price.


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terminated that service.)