; ***************************************************************************
; copyright   : (C) 2025 by Martin Preuss
; email       : martin@libchipcard.de
;
; ***************************************************************************
; * This file is part of the project "AqHome".                              *
; * Please see toplevel file COPYING of that project for license details.   *
; ***************************************************************************

#ifndef AVR_MODULES_COM2W_COM2WN_SEND_H
#define AVR_MODULES_COM2W_COM2WN_SEND_H


; WORK IN PROGRESS



.cseg



; ---------------------------------------------------------------------------
; @routine com2wSendMsg
;
; @param X pointer to bytes to send
; @param Y pointer to interface data in SRAM
; @return CFLAG set if message sent, cleared otherwise
; @clobbers R16, R18 (R20, R22, R24, R25, X)

com2wSendMsg:
  ldi r20, 6                             ; wait for about 60us for clock low
  rcall com2wWaitForClockLowMulti10Us    ; (R17, R20, R22)
  brcs com2wSendMsg_busy                 ; CLK got low while waiting, so line is busy
  push r15
    in r15, SREG
    cli                                  ; atomic disable irq and set CLK low
    rcall com2wDisableClkIrq             ; (none)
    rcall com2wClkSetLow                 ; reserve bus (none)
    out SREG, r15
  pop r15
  adiw xh:xl, NETMSG_OFFS_MSGLEN
  ld r18, X
  sbiw xh:xl, NETMSG_OFFS_MSGLEN
  inc r18                                ; adjust for DESTADDR
  inc r18                                ; adjust for MSGLEN
  inc r18                                ; adjust for CRCBYTE
  rcall com2wWaitTime1                   ; longer wait period (R22)
  rcall com2wSendBytes                   ; (r16, r17, r18, r22, X)
  rcall com2wClkSetHigh                  ; make sure bus is released
  rcall com2wDataSetHigh

  rcall com2wEnableClkIrq                ; (none)
  ldi r16, NET_IFACE_OFFS_PACKETSOUT_LOW
  rcall NET_Interface_IncCounter16       ; (R24, R25)
  sec
  ret
com2wSendMsg_busy:
  ldi r16, NET_IFACE_OFFS_ERR_BUSY_LOW
  rcall NET_Interface_IncCounter16       ; (R24, R25)
  clc
  ret
; @end



; ---------------------------------------------------------------------------
; @routine com2wSendBytes
;
; @param  R18 number of bytes to send
; @param X pointer to bytes to send
; @param Y pointer to interface data in SRAM
; @clobbers: r16, r18, X (r17, r22)

com2wSendBytes:
com2wSendBytes_loop:
    rcall com2wClkSetLow                      ; (none)
    rcall com2wWaitTime1                      ; longer wait period (R22)
    ld r16, X+
    rcall com2wSendByte                       ; (R16, R17, R22)
    dec r18
  brne com2wSendBytes_loop
  ret
; @end



; ---------------------------------------------------------------------------
; @routine com2wSendByte
;
; @param R16 byte to send
; @param Y pointer to interface data in SRAM
; @clobbers r16, r17 (r22)

com2wSendByte:
  ldi r17, 8
com2wSendByte_loop:
    rcall com2wClkSetLow
    rcall com2wWaitTime1                        ; longer wait period (R22)
    lsr r16
    brcs com2wSendByte_send1
    rcall com2wDataSetLow
    rjmp com2wSendByte_sent
com2wSendByte_send1:
    rcall com2wDataSetHigh
com2wSendByte_sent:
    rcall com2wWaitTime2                        ; shorter wait period (R22)
    push r15
      in r15, SREG
      cli                                       ; ensure time period by disabling irqs
      rcall com2wClkSetHigh
      rcall com2wWaitTime1                      ; longer wait period (R22)
      out SREG, r15
    pop r15
    dec r17
  brne com2wSendByte_loop
  ret
; @end



; ---------------------------------------------------------------------------
; @routine com2wWaitTime1
;
; waits for longer period (e.g. 30ns)
;
; @clobbers R22

com2wWaitTime1:
  Utils_WaitNanoSecs COM2W_WAITTIME1, 7, r22            ; wait for longer time (minus RCALL and RET)
  ret
; @end



; ---------------------------------------------------------------------------
; @routine com2wWaitTime2
;
; waits for shorter period (e.g. 10ns)
;
; @clobbers R22

com2wWaitTime2:
  Utils_WaitNanoSecs COM2W_WAITTIME2, 7, r22            ; wait for shorter time (minus RCALL and RET)
  ret
; @end







#endif ; AVR_MODULES_COM2W_COM2WN_SEND_H