spi2.fs

\ hardware SPI driver, 2nd device

PB11 variable ssel2  \ can be changed at run time
PB13 constant SCLK2  
PB14 constant MISO2  
PB15 constant MOSI2  

: +spi2 ( -- ) ssel2 @ ioc! ;  \ select SPI
: -spi2 ( -- ) ssel2 @ ios! ;  \ deselect SPI

: >spi2> ( c -- c )  \ hardware SPI, 8 bits
  SPI2-DR !  begin SPI2-SR @ 1 and until  SPI2-DR @ ;

\ single byte transfers
: spi2> ( -- c ) 0 >spi2> ;  \ read byte from SPI
: >spi2 ( c -- ) >spi2> drop ;  \ write byte to SPI

: spi2-init ( -- )  \ set up hardware SPI
  OMODE-PP    ssel2 @ io-mode! -spi2
  OMODE-AF-PP SCLK2   io-mode!
  IMODE-FLOAT MISO2   io-mode!
  OMODE-AF-PP MOSI2   io-mode!

  14 bit RCC-APB1ENR bis!  \ set SPI2EN
  %0000000001010100 SPI2-CR1 !  \ clk/8, i.e. 9 MHz, master
  SPI2-SR @ drop  \ appears to be needed to avoid hang in some cases
  2 bit SPI2-CR2 bis!  \ SS output enable
;