ioi   ld    a, (SPI_SLAVE_CS_REG)  ; read the CS register
         bit   SPI_SLAVE_CS_BIT, a    ; is CS true?
         jr    nz, SPIWrite_cont      ; jump if yes - high true 
         xor   a                      ; a = 0 = show no CS
         ld    l, a                   ; set
         ld    h, a                   ;  return value
         ret
SPIWrite_cont: