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Timeclock


GDMike

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1)Difficulty is such a relative term. I believe I could tackle this sucsessfully, but I would first need to clear up some personal issues... this would require a generous supply of LGAMs (lawyers, guns and monies)

 

2)In due consideration of the need for selection of an electrical interface and a programming language, along with any compatibility issues. It helps to have clear final goals in mind.

 

Because of it's single bidirectional I/O pin, this device seems like a good candidate for interfacing to the TI's parallel port, as it is also bi-directional. However I have little exp. with programming for the parallel port.

 

The 9901's pins are effectively unidirectional, thus requiring two separate pins, one for INPUT and one for OUTPUT.

 

If I interpret the DS1302 specs. correctly, it's I/O pin provides INPUT or OUTPUT only while both CE is high and SCLK is low. This does not provide for simple logic gating, required to ensure that DS1302 OUTPUT does not coincide with 9901 OUTPUT.

One simple solution would be to use an additional 9901 OUTPUT pin to buffer(tri-state) the other 9901 OUTPUT pin, under program control.

 

Once the electronic interface is in place, a simple TSR could be called from XB, or TI BASIC w/MINIMEMORY by using CALL LINK.

 

Perhaps it would be posible to drive the CRU's pins directly from one of Rich's XB versions ...sounds a bit cumbersome though.

 

I also have an ASSY program written by "yours truly" that does basically if not exactly what the DS1302 does, but requires an external periodic CLK pulse. Mine also provides, Week of Month, but does not currently include seconds. Designed to drive my Scheduler Program.:)

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Pretty much all the 9901 pins are already used, but it's fairly easy to add a second 9901 to the console by piggybacking it on the existing one and mapping it to unused CRU address (>0400 or >0800?). If you've got a RAMDisk in your system and have the source code for the DSR, then it is fairly easy to add a new device entry (so you don't need to mess around with the hardware to support a separate DSR just for the clock), and then add the software to support opening and reading/writing to the clock. That's how I added support for a parallel keyboard interface many many years ago.

Edited by Stuart
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Im just getting lazy and forgetting to time/date my work source files lately, and this time it cost me. Still digging for a dated file..But as good as I am, uh hm, I will rewrite what is missing. But things like this are fixable, I hope!

I do have a ramdisk shell. I'm trying to put parts into it to make it a basic ramdisk, while hoping I could interface this little clock..but in not holding my breath in getting this card to function, as it's a new area for me to work within.

Just wish me luck! Hey, thanks so much for the feedback, it gives me some hope.

Edited by GDMike
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The DS1302 uses a 3-wrie interface which will be much easier to deal with by using a microcontroller to interface it to the 99/4A.  Of course that means the microcontroller could also conveniently implement the CRU logic and DSU code.

 

Alternatively, the DS12885 could be used and memory mapped into some unused / repeated memory space.  This would not have the advantage of a DSR though, but would be simpler and faster to use and access.

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Yes..I'm a little slow getting this, but Mr.p said he made an address based PEB clock card and it's seen at >4000 he has some schematic somewhere, and I've asked him if he'd like to share.

I grabbed this chip outta da air..as a place to start as I didn't Know any better.

Thx

Edited by GDMike
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