Interfacing C4PMF with X-10

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Interfacing C4PMF with X-10

Post by lowrybt1 » Thu Aug 17, 2017 9:49 pm

Assuming I'm never going to find a CA-25 header card, I'm looking at ways to interface a Challenger running OS65D with a "modern" X-10 controller. There is a device that attaches to serial ports call a "Firecracker." X-10 Firecrackers appear to be readily available.

How does it work? You send a specific Hex number to the Firecracker attached to the serial port and it will in turn send RF signals\commands to an X10 controller. The command must be preceded by a header and footer (both numbers) For the fun of it, I'm going to give this a try with a C4P. Sending the Hex numbers\codes should be easy enough using Print #1 or poking the numbers in sequence via location 65413. But there is one piece I need guidance with....

Before sending the header, footer and command to the Firecracker, it needs to be toggled on and off (reset and placed in standby mode). This is accomplished by setting the DTR and RTS lines low and then high, in rapid sequence. Here's the question: how might that be done with C4PMF printer port? Is there a poke statement of Disk!"IO command that could accomplish that?

Thanks, Tom
C4PDF w. 24K, 2 x 5.25 MPI B-51 drives
C1P RevB with fully-populated 610 board and A-13. Klyball D-13.
Spares: 600 Rev.D, 610 board, 540A, A-13 with homebuilt data separator, MPI B-51 logic board (w/o data sep module) and mechanicals

Steve Gray
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Location: Markham, Ontario, Canada

Re: Interfacing C4PMF with X-10

Post by Steve Gray » Fri Aug 18, 2017 1:46 am

I have something called the "IBM Home Director". It also has a standard rs232 interface to control x10 modules. Recently i saw some of these kits on ebay for relatively cheap prices...

C4P working, C1P working. 600D Replica working, C4P+D&N floppy not working. 505 board, 610 board, Mittendorf board, TOSIE hacker board need testing, PicoDOS disk untested.

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Re: Interfacing C4PMF with X-10

Post by dave » Fri Aug 18, 2017 3:18 pm

The 6850 has an /RTS line that can be controlled via bits 5 and 6 of the ACIA control register at $FC00 (64512). I don't think interrupts are supported, so you can just use bit 6. Setting it to 0 brings /RTS low, and setting it to 1 brings /RTS high.

Depending on your 505 board setup, you may need to set a jumper to make sure you're getting the /RTS signal to the connector.

I don't see a DTR line on the osi schematic, but if you're not using DTR for handshaking, you could connect it to the /RTS line, and drive them both together.

If you're doing hardware handshaking, that may be a problem, but if both lines are kept high except during the reset, then that may do the trick.

Good luck,


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