VersaLogic EBX-22, Reference Manual, Page: 71 / 83

Interfaces and Connectors
EBX-22 Reference Manual
65
SPI “B
IT
B
ANG
” M
ODE
A special register is available at 1D7h, which enables the direct control (“bit banging”) of the SPI
interface. To use this register, the SPI field (bits D6-D5) of the MODCON register (1DFh) must
be set to 0h (see Table 44 for mode control settings).
SPIBB (Read/Write) 1D7h
D7 D6 D5 D4 D3 D2 D1 D0
SPI_IN SPI_INT SPI_CLK SPI_OUT SPI_CS3 SPI_CS2 SPI_CS1 SPI_CS0
Table 33: SPIBB Bit Assignments
Bit Mnemonic Description
D7 SPI_IN SPI Input – This bit is read-only.
D6 SPI_INT SPI Interrupt – This bit is read-only.
D5 SPI_CLK
SPI Clock – This bit is read/write.
D4 SPI_OUT
SPI Output – This bit is read/write.
D3-D0 SPI_CS
SPI Chip Select – These bits are read/write.
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