SPI XDR

There is a SPI controller which support :

half/full duplex
single/dual/quad SPI
SDR/DDR/.. data rate

You can find its APB3 implementation here :

https://github.com/SpinalHDL/SpinalHDL/blob/68b6158700fc2440ea7980406f927262c004faca/lib/src/main/scala/spinal/lib/com/spi/xdr/Apb3SpiXdrMasterCtrl.scala#L43

Configuration

Here is an example.

Apb3SpiXdrMasterCtrl(
  SpiXdrMasterCtrl.MemoryMappingParameters(
    SpiXdrMasterCtrl.Parameters(
      dataWidth = 8, // Each transfer will be 8 bits
      timerWidth = 12, // The timer is used to slow down the transmission
      spi = SpiXdrParameter( // Specify the physical SPI interface
        dataWidth = 4, // Number of physical SPI data pins
        ioRate = 1, // Specify the number of transfer that each spi pin can do per clock 1 => SDR, 2 => DDR
        ssWidth = 1 // Number of chip selects
      )
    )
    .addFullDuplex(id = 0) // Add support for regular SPI (MISO / MOSI) using the mode id 0
    .addHalfDuplex( // Add another mode
      id = 1,  // mapped on mode id 1
      rate = 1, // When rate is 1, the clock will do up to one toggle per cycle, divided by the (timer+1)
                // When rate bigger (ex 2), the controller will ignore the timer, and use the SpiXdrParameter.ioRate
                // capabilities to emit up to "rate" transition per clock cycle.
      ddr = false, // sdr => 1 bit per SPI clock, DDR => 2 bits per SPI clock
      spiWidth = 4 // Number of physical SPI data pin used for serialization
    ),
    cmdFifoDepth = 32,
    rspFifoDepth = 32,
    xip = null
  )
)

Software Driver

See :

https://github.com/SpinalHDL/SaxonSoc/blob/dev-0.3/software/standalone/driver/spi.h https://github.com/SpinalHDL/SaxonSoc/blob/dev-0.3/software/standalone/spiDemo/src/main.c