6502-OS/system/spi.h65

;;********************************************************************************
;; @module SPI-P
;; @details
;;  Support being a peripheral SPI device.
;; @depends IO-W65C22N
;;********************************************************************************
.ifndef INCLUDE_SPI
INCLUDE_SPI = 1

.include "system/system.h65"

;;********************************************************************************
;; @brief Support being a peripheral SPI device
;; @details
;;  This requires the data line to be hooked up to `CB2` and the clock to `CB1`.
;;  The VIA will be set to shift in the data into the shift register under the external clock.
;; @ingroup drivers
;; @see via_hardware_bug "VIA external clock bug"
;;********************************************************************************
.scope spi_p

;; Address of the VIA that is used for the spi connection
SPI_IO = IO2
Import spi_p, init, irq_handler, status, buffer_size, recv_size
ImportZp spi_p, buffer_ptr
Import spi_p, begin_read, end_read, irq_read_byte, recv_bytes
Import spi_p, begin_write, end_write, irq_write_byte, sent_bytes


;;********************************************************************************
;; @brief Status of a SPI transfer 
;;********************************************************************************
.enum STATUS
    XFER_SIZEL  = %10000000
    XFER_SIZEH  = %01000000
    XFER        = %00000001
    DONE        = %00000000
    ERROR       = %00100000
.endenum

.endscope
.endif  ; guard

; .struct SPI_P_Pins
;     ; VIA addresses
;     DDR_a   .word   ; address of the data direction register
;     R_a     .word   ; address of the register
;     ; pin mask
;     SCLK_p  .byte   ; Serial Clock
;     POCI_p  .byte   ; Peripheral Out / Controller In
;     PICO_p  .byte   ; Peripheral In / Controller Out
;     CSB_p   .byte   ; Chip Select
;     ; settings
;     CPOL    .byte   ; Clock Polarity
;     CPHA    .byte   ; Clock Phase
; .endstruct