Each card has no less than 4 each 1uF ceramic caps distributed along the power busses. The cards are RS# 276-168B one card is fashioned into a 5 slot backplane with 30 pin headers, into this are 3 cards, one housing the Arduino Micro, one containing the 2 597's and the third having 3 CD4069's serving as signal conditioners for an array of RC pulse delays. The delay card serves the 597's with data inputs and a reference STCK such that a parasitic capacitance change from a touch pad causes the rising edge of the channel's strobe to arrive after STCK (key presence, logical 0) or before STCK (key no presence, logical 1). My initial design used a LS374 for capture, then would have been used to load a 597, but I realised the storage register could facilitate the same function as the preceding LS374 without requiring 2 additional chips and the real-estate associated therewith. I am not using the SPI built in hardware, it will be required later for the 32 channels of source drivers. I would also like to thank-you for the response.