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UPS was Kind to Me Today

A box containing 250 of the Molex connectors arrived today so now I’ll be populating lots of SS-50 boards again.  They arrive in trays of 56 connectors, two of which are here:

Speaking of rebuilding my inventory, I’ll have a lot of items for show/sale at Vintage Computer Festival East in New Jersey, May 18-20.  There are a few vintage computer festivals around the country, but the one in NJ is definitely big compared to the rest.  Besides being a great time to see and use our products, there are dozens of excellent displays of vintage computer systems, so it’s a great chance to see a lot of the systems you missed or couldn’t afford at the time.

I’ve been using github to hold most of the engineering documents for our products, including CAD files, source code, documentation, etc.  In the near future I’m going to start making some of the projects public, particularly the source code to the SD shield, our extensions to SBUG, xSWTBUG, the KIM Clone monitor, etc.  Customers have noted that some of the code on the thumb drive is older than what’s actually shipped with products so it makes sense to just put the code in public git repositories so the latest is always available.  I’m also hoping others will pick up the code and do more with it.  Despite my enthusiasm to write code, design hardware and produce a few dozen products, I also have a day job, family, and sometimes need some down-time to play with other interests.  Having the code public means others can free access to it and can put their extensions on-line for others.

This weekend I’m helping my wife with a STEM weekend at a local Girl Scout camp so the soldering iron will be turned off most of Saturday.


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All Kinds of Stuff

First, we’re watching the TV a lot hoping for the best for Florida.  My family enjoys vacationing each year in Marco Island, which seems to be exactly where Irma is heading.  A number of our friends got out of the state in time so we’re hoping they’ll be able to return home to find little damage.

Next week my son goes to college which means I’ll be pretty much gone all next weekend and most likely doing final preparations this week during the evenings.  There might be little accomplished here for the next week in terms of Corsham Tech projects but I will do my best to answer emails.

VCF Midwest (just west of Chicago) is happening this weekend.  Normally I’d be there but my new full-time job is keeping me busy and I just didn’t want to miss a couple days of work.  Yes, I really enjoy what I do for a full-time job, which is writing embedded software.

KIM Clone status… I spent the last two weeks chasing a “software” problem and the finally realizing last night that my design was right for a 6502 but had a slight error for using a 65C02.  Once the fix was applied the 65C02 worked perfectly.  The design has been updated to accommodate either chip.  My plan is to ship with a 65C02 but all of my code is written for the 6502 so it will work with either chip.  There is one annoying problem that I know how to fix but just didn’t have time yet to address: the FT232RL backfeeds power into the main circuit, and it’ll take a couple more surface mount parts to fix.  The other outstanding hardware problem is that single step doesn’t work; it appears that a single jumper might fix it.

That’s enough for now… there is work to be done!


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This board is targeted to 6809 based systems which have a 4K EPROM window from F000 to FFFF.  By default, the EEPROMs included with all our systems are 8K (28C64) because it’s easier for me to stock one EEPROM instead of multiple ones.  The lower 4K is not accessible, and SBUG is in the top 4K.

As some of you know, we’ve been looking at getting a port of OS/9 and while working with the OS/9 experts it was decided that a custom EPROM image with most of OS/9 in it would be a better solution that have 4K of SBUG and then using a lot of RAM for the OS.  I didn’t want to make a customer choose between flashing either OS/9 or SBUG, so it was suggested to make a small add-on board with DIP switches to select which image to load.

Here is that board:

SW1 controls A12 and SW2 controls A13, so by setting them appropriately and with the right size EPROM, this board allows up to four boot images to be in memory from E000 to FFFF.  Since I use 8K EEPROMs, only two images are available, but a customer can also use a 28C128 which allows four images.

The price for this board assembled and tested without an EEPROM is $20.  Kit is $15, and a bare board for $10.  Free shipping in the US, of course.

I can hear your next question: “So is OS/9 available?”

No, but extremely close.  Boisy Pitre and I worked at VCF SE and made a lot of progress.  I made changes to the EEPROM code and Arduino code, as well as to the motherboard to allow everything to work.  He did all the code changes in NitrOS/9 to support the Corsham Tech boards.  I’ve had a preliminary version running for about a month now and it’s very nice.  Boisy is working to get the changes into the official distribution and then it will be available.  In the picture above, SW1 selects SBUG or NitrOS/9 boot… ON is Flex, OFF is NitrOS/9.

Close, very close.