Finally! A product that is easy and Straightforward to review. I’m speaking of the BB-1 control module from Byte-Back, Rt. 3 Box 147 Brodie Road, Leesville, SC 29070. It is easy to review because it is easy to understand, easy to build and easy to implement. When you open the package, you find all your parts neatly organized into envelopes, with a comprehensive set of instructions that will guide you through the steps to turn that collection of parts into a working I/O board. When you’re done, an evening later, you’ll have a nifty little board that gives you the heart of any number of dedicated control applications. Basically, the device consists of two PIO chips, (one for input, one for output), eight reed relays for output control, and the necessary decoding and buffering circuitry. Because of its two I/O chips, the BB-1 is almost like two boards; not only can you control up to eight different circuits or devices, you can also get the logic status of eight input circuits or devices. A nice touch is the on-board regulator and heatsink. Other nice touches are the plated and masked board, on-board status LED’s for output indication (just great for debugging), and a competent yet uncondescending attitude in the manual.
The board is decoded at addresses 16381 (for input) and 16382 (for output). PEEKing 16381 gives you a number that, on conversion to binary, gives you which input lines are pulled to ground (active low), Similarly, POKEing 16382 with the desired number actuates the relays and indicator LEDs. Byteback warns against having anything else in this memory range, but I’ve tried it on two 64K RAMs and on the Hunter board, and it works flawlessly even if that block is already in use by RAM. Of course, you can’t put anything else in these addresses, but I’ve found no problems due to the apparent conflict. Additional boards can be decoded for other addresses, to give you as many lines as you’d care to wire up. The output circuit has an on-board latch to keep the output status the same even if you NEW the computer; only a POKE or LD into 16382 (3FFEh) will change the status. The on-board relays are the tiny DIP reed variety which are fine for controlling low-level currents like other TTL stuff, analog summing amps, etc. but should be used to control other (external) relays to handle loads over about -5A resistive, and any non-resistive loads. Or use power transistors or triacs (for DC or AC respectively). You could replace the relays with opto-couplers if you need the faster response.
This board ($59 kit, $69 A&T) is a good buy for those who wish to get into outside control and aren’t afraid of the basic electricity aspect of it, but would rather not get into decoding, PIO, latches, buffers, drivers and all that sort of thing; an evening of pleasant kit-building, and you’re ready to hook it up to your bells and whistles. We do recommend that you get sockets for the PIO (and other) chips just in case you blow one out; Byte-Back doesn’t supply them. I got lazy and soldered mine in, and haven’t had any trouble (Yet). You’ll also need an edge connector to the relay and input lines, unless you plan to hard-wire the board. Other than that, there are no surprises. You wire it up, it works, Now what you do with it is up to you; if you can turn it on and off with a switch, you can turn it on and off using your computer.
EDITOR’s NOTE: So what am I doing with it? As I mentioned in the intro, I’m building a machine to measure battery performance, based around a TS1500. The BB-1 is used to select the charge/discharge current (first 5 bits), charge or discharge mode (6th bit), turn the cassette motor on and off and select VOTEM mode (7th bit), and select LOAD or SAVE (8th bit) to prevent feedback or ground-loop problems with the recorder.