DiGidot C4 Extended Manual page 22

4X SPI OUT
Average recommendation is max. 3 SPI universes per port (check the C4 Performance guide for max. load per IC) | SPI cable length max. 2
m. (7 ft.)
This option shows four SPI Data only outputs. Each SPI Ground wire must be the same length as the
Data wires per output, to prevent timing issues.
2 x SPI DATA + CLOCK OUT
Average recommendation is max. 6 SPI universes per port (check the C4 Performance guide for max. load per IC) | SPI cable length max. 2
m. (7 ft.)
This option shows two SPI Data + Clock signals. Please note that all grounds must be connected.
C4 Manual Version 2.2.0 22-78