This is the Grits Programmable I/O Board for the PC/104 bus.  U1, the Lattice ispLSI2096A, is the only active component on the board.   All other parts on the board are passive devices, either resistors, capacitors, or resistor networks.  U1 is programmed through port P2 in the upper-right corner.  The socket at U2 allows the addition of an oscillator should a new application require it.

This is the top of the Grits Board shown without any components.  Because U1 is fully programmable, it was possible to route the signals directly without signals having to cross, even using the surface mount components which are normally thought to require lots of vias.  This is a two-layer board. 

This is the bottom of the Grits Board shown without any components.  There is a continuous ground plane under all high-speed signal lines, which helps reduce electromagnetic interference (EMI).

This is the Cornbread Programmable I/O Board.  U1, the Lattice ispLSI2096A, is the only active component on the board.   All other parts on the board are passive devices, either resistors, capacitors, or resistor networks.  U1 is programmed through port P2 in the upper-left corner.  The socket at U2 allows the addition of an oscillator should a new application require it.

This is the top of the Cornbread Board shown without any components.  Because U1 is fully programmable, it was possible to route the signals directly without signals having to cross, even using the surface mount components which are normally thought to require lots of vias.  This is a two-layer board. 

This is the bottom of the Cornbread Board shown without any components.  There is a continuous ground plane under all high-speed signal lines, which helps reduce electromagnetic interference (EMI).

This is the Flapjack Programmable I/O Board.  This board was designed to be buildable without having to deal with surface mount parts.  All parts are either through-hole types, or are mounted in through-hole sockets.  U1, the Lattice ispLSI1032E, is the only integrated circuit on the board.  Transistor Q1 is required to drive one bus line because the Lattice ispLSI1032E does not support open-drain outputs.  All other parts on the board are passive devices, either resistors, capacitors, or resistor networks.  U1 is programmed through port P4 in the upper-left corner.   The socket at U2 allows the addition of an oscillator should a new application require it.

This is the top of the Flapjack Board shown without any components.  Because U1 is fully programmable, it was possible to route the signals directly without signals having to cross. This is a two-layer board. 

This is the bottom of the Flapjack Board shown without any components.  There is a continuous ground plane under all high-speed signal lines, which helps reduce electromagnetic interference (EMI). 
 

This is the board which precipitated the idea of a fully programmable I/O board. This is a four-layer board, with 74F245 line drivers to match a customer requirement. This design was optimized to drive the customer specified cables to a remote unit.  The lessons learned on this development were incorporated into the first I/O board designed for FreeIO.org, the Cornbread board.

                                                 . . . . . . . . . .