Mo & Terry Smedley

H8 Prototyping Frame

This is an update to the Heath H8-7 Breadboard.  The concept is a static "frame" that contains all the bus interface and power supply circuitry, with a replaceable middle section for the prototyping card of the user's choice.  It was designed for solder or solderless prototyping boards, and is not ideal for wire wrapping.  The bus interface contains fully buffered input, output, and bidirectional data ports, all brought out to "KK" headers.  Oscilloscope test points are available for all bus control signals.  There are five LEDs available for debugging (three static, and two pulse-stretched).  +3.3v, +5v, and +12v regulated and fused power supplies are on the board, accessible from a polarized "KK" header as well as solderless breadboard connections.  It is most suited for Eurocard 3U (160mm x 100mm) prototype cards, or the Radio Shack 276-168B mini-prototype card.

There is room on the board for a 3M TexTool 20-pin ZIF socket for the GAL decoder.  The GAL programming is likely to change from project to project, and the ZIF socket will prevent board damage caused by repeated insertions and removals of the GAL.

PCB designs for protoboards similar to the Radio Shack 276-168B are also found here, in four different hole patterns (1x3, 2x3, 1x4, and 2x4).  See the X-Ray views for the clearest distinction between the different patterns.  The Radio Shack board used 1x3 patterns with no solder-resist coating, one-side only.  The 1x3 pattern board here has a very similar electrical pattern, but has through-hole plating and solder resist.