6502-OS/system/spi.s65

;********************************************************************************
; @module SPI
; @type driver
; @details
; @depends IO-W65C22N
;********************************************************************************

.include "system/system.s65"
.include "programs/print_slow.s65"

.ifndef INCLUDE_SPI
INCLUDE_SPI = 1


.bss
SPI_PAGES_WRITTEN:  .res 1
SPI_BYTES_WRITTEN:  .res 1
.segment "SPI"
SPI_CODE_START:     ; .res $1000
    lda $1000
    sta $1000
    lda $1000
    sta $1000
    lda $1000
    sta $1000
    lda IO1 + IO::RA
    lda IO1 + IO::RA
    bra SPI_CODE_START
    ; jsr lcd_clear
    ; PrintSlow msg,20
    ; jmp home
; msg:
    ; .asciiz "YO DAS WAR    SPI"



.code
.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

;********************************************************************************
; @function Initialize the IO Adapter for SPI
; @param ARG0-1 Address of the SPI_Pins struct
;********************************************************************************
.proc spi_p_init
    stz SPI_PAGES_WRITTEN
    stz SPI_BYTES_WRITTEN
    ; todo USE MASKS
    ; set Shift register to shift in under external clock on CB1
    lda #IO::ACR::SR_SIN_PHIE
    sta SPI_IO + IO::ACR

    ; enable SR interrupts
    lda #(IO::IRQ::IRQ | IO::IRQ::SR)
    sta SPI_IO + IO::IER
    DEBUG_LED_ON 1
    rts
.endproc

.proc spi_p_read
    DEBUG_LED_ON 0
    ; print received byte
    lda SPI_IO + IO::SR
    sta SPI_CODE_START,x
    inc SPI_BYTES_WRITTEN
    jsr lcd_char
    rts
.endproc

    
;********************************************************************************
; @function Read bytes
; @param X Number of bytes to send
; @param ARG0-1 Address of the SPI_Pins struct
; @param ARG2-3 Address of the first byte
;********************************************************************************
.proc recv_data
.endproc
;********************************************************************************
; @function Send bytes
; @param X Number of bytes to send
; @param ARG0-1 Address of the SPI_Pins struct
; @param ARG2-3 Address of the first byte
;********************************************************************************
.proc send_data
.endproc

    

_send_byte:
    
.endif