Hi Josh!
I'd like 3 boards myself, when ready for production!
Thanks,
Fabio
On Jun 5, 2014 7:55 AM, "Crusty OMO" <[email protected]> wrote:

> Thanks Tom,
>
> I'll put you down for 2 boards and 3 LM323K's.  I'll try to make trip
> across the boarder to ship them from the US side... let's see how the
> timing works.
>
> Cheers,
> Josh Bensadon
>
>
> ------------------------------
> Subject: Re: [N8VEM-S100:3966] ALTAIR/IMSAI 8080 CPU replacement board
> From: [email protected]
> Date: Wed, 4 Jun 2014 22:35:06 -0400
> To: [email protected]
>
> I'll take two when your ready
>
>
> Good work.
>
> ~~ _/) ~~~~ _/) ~~~~ _/) ~~~~ _/) ~~
> Sent from my Phone
>
>
> On Jun 4, 2014, at 10:19 PM, Crusty OMO <[email protected]> wrote:
>
> Hi Guys,
>
> Well I'm finally done laying out this board.  The autorouter only produced
> swiss cheese with over 900 via's.  It looked terrible!
> Anyway, I scrapped everything the autorouter did initially, and proceeded
> to layout the traces manually.  Once I got what I thought was all the hard
> parts done, I let the autorouter have another go at it.  Again it did not
> work out so well and it was unable to complete the board, so I proceeded to
> undo it's changes and/or improve it's routing manually.  I squeezed those
> traces in there tight, any tighter and they'll be popping off the board.
> Anyway, I'm working on the silkscreen layer and ready to do a run.
> Here's a picture of the board layout....
> You can see the serial port connections on the top left, SD card to the
> right of the 27C256 EPROM, parallel ports next to that and the ALTAIR and
> IMSAI front panel connectors.  There are also a few jumpers around the
> board to configure for CPU or Peripheral board only and ALTAIR/IMSAI mode.
> Firmware for the board will be my next project, but I have to make
> preparations for VCF-MW my priority.  Dave Ruske and I will be doing a
> COSMAC 1802 exhibit there in September.
>
> <Pic.bmp>
>
>
> Cheers,
> Josh Bensadon
>
>
>
>
> ------------------------------
> From: [email protected]
> To: [email protected]
> Subject: RE: [N8VEM-S100:3711] ALTAIR/IMSAI 8080 CPU replacement board
> Date: Sun, 18 May 2014 00:57:20 +0000
>
> Hi Guys,
>
> Well, this project has just reached a milestone.  The hardware is tested
> and working.  I had some rewiring to do to make it work for the ALTAIR, I
> thought the ALTAIR and IMSAI front panels were (near) identical, but they
> are not.
> There are some jumpers on the board to configure between ALTAIR and IMSAI.
>
> Here's a picture of my debugging and testing setup.  The board is being
> tested in the ALTAIR.
>
> <IMG_1527.JPG>
>
>
> Now entering Phase 2... building a PCB.
>
> Cheers,
> Josh Bensadon
>
>
> ------------------------------
> From: [email protected]
> To: [email protected]
> Subject: RE: [N8VEM-S100:3666] ALTAIR/IMSAI 8080 CPU replacement board
> Date: Tue, 13 May 2014 13:56:05 -0700
>
> Very nice Josh!
>
> John
>
>
>
> *From:* [email protected] [mailto:[email protected]
> <[email protected]>] *On Behalf Of *Crusty OMO
> *Sent:* Tuesday, May 13, 2014 1:19 PM
> *To:* [email protected]
> *Subject:* RE: [N8VEM-S100:3664] ALTAIR/IMSAI 8080 CPU replacement board
>
>
>
> Hi Group,
>
> Well, I'm cooking up this board at the moment.  I have all the hardware
> figured out to run like the original CPU boards.
> I need to do a little more testing of the hardware, then I'll proceed to
> building the boards.
> The Memory, I/O, UARTs and SPI interface to the SD card appear to all be
> working.
> 8K chunks of memory can become either ROM, RAM or mapped off the board.
>
> CPU: 8080A
> UARTS: 2x 8250
> RAM: 2x 32K
> ROM: 32K
> I/O: 8 input, 6 output pins
> SPI to SD Card interface
> ALTAIR & IMSAI Front Panel Connectors.
>
> Where ROM is selected in a block it overlaps the RAM on reads, but writes
> go through to RAM.
> The ROM can then be disabled and reads will come from the RAM at that
> location.
> The firmware is copying itself to RAM then switching off the ROM.
> The CPU can be deselected with jumpers and the board will work as RAM/ROM
> and I/O for another CPU on the bus.
>
> Pictures attached.  Yellow-Data, Brown-Address, Blue-I/O,
> Green-Control/Status & everything else.
>
> Regards,
> Josh Bensadon
>
>
>
>
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