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McTrinsic

Posted Fri Apr 24, 2020 11:59 am

Doesn’t work, tried that :).

An example: the driver for the Melody 1200 checks for the pcmcia device in RAM. Unfortunately, that is only in RAM if there is the respective hardware...

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Harjit

Posted Sun May 10, 2020 9:09 am

Back in 1986/1987, my friend, Jim Rothrock and I made a battery backed up real time clock called LittleBen which plugged into the second mouse port.

Jim wrote the software and I designed and built the hardware. I think we sold about 30 of them. They were all hand built. It was my first experience in running a business - IIRC, we broke even on the hardware but didn't make enough money to pay Jim for writing the software. I designed the circuit, printed circuit board, had them manufactured, called around and got quotes for all the parts, ordered the "best deal" - back then shipping was like $2.xx for a package! Then, I hand assembled them. This was the most challenging part because it was a lot of soldering and doing it at home without a great workbench was difficult. Then, I had to let them run for a little bit so that I could fine tune the frequency so that they didn't gain or lose time, make sure the battery was charging and holding charge, etc.

I did the hardware development on an Atari 800 using Action! (https://en.wikipedia.org/wiki/Action!_( ... _language)) since I was more familiar with that setup than my Amiga. Jim looked at it and ignored it and wrote his own version.

Inside, it had a Signetics chip (now NXP), a NiCd battery which was charged from the port, a variable capacitor to trim the frequency and a couple of other resistors, capacitors and I think a diode (for charging).

I've attached a picture of the manual, hardware unit, and the chips that were in it.
Attachments
LittleBen.jpg

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Christian

Posted Mon May 11, 2020 9:16 pm

Thanks for sharing. You used the same RTC chip that Microbotics used in the Stardrive and Multifunction Modules for the Starboard 2.
Maybe also in the MouseTime.
I hadn’t seen that chip being used much, but then again the Oki and Ricoh Chips used with the later Amiga models are probably also not that common.

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JoeUser
Dallas, TX

Posted Mon Mar 29, 2021 7:05 am

Back in 1986/1987, my friend, Jim Rothrock and I made a battery backed up real time clock called LittleBen which plugged into the second mouse port.
Looks like it'd be a fun little project board to build! Have you considered releasing the info publicly, to see if anyone wants to "pick up the mantle" and produce these for A1000 owners? That'd be awesome, I'd certainly buy one if someone (or yourself) built these. Heck, I'd even buy one in kit form and put it together myself 8-)

Just dreaming, but if the board could be fabbed with a pass-through for the DB-9 connector, so that it would be like the Microbotics model (plugged directly into the port, with no cable), would that work? Or, would passing mouse signals through disrupt the timing signal?

Anyway, thanks for sharing the history!

Edit: Just for grins, I just did a quick search for 68000 RTC's, and came across this (and its GitHub):

https://www.sparkfun.com/products/10160
https://github.com/sparkfun/DeadOn_RTC/tree/v1.1

I wonder if something like this would work, using either the keyboard cable method or mouse port, for the A1000?

Edit: Bump





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