; ***************************************************************************
; 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.   *
; ***************************************************************************


.cseg



; ---------------------------------------------------------------------------
; @routine UART_HW_Interface_Init @global
;
; @param Y pointer to interface data in SRAM
; @clobbers R16 (R17, X)

UART_HW_Interface_Init:
  rcall NET_Interface_Init                  ; (R16, R17, X)
  ldi r16, 0xff
  std Y+UART_HW_IFACE_OFFS_READBUFNUM, r16
  std Y+UART_HW_IFACE_OFFS_WRITEBUFNUM, r16
  ldi r16, UART_HW_READMODE_IDLE
  std Y+UART_HW_IFACE_OFFS_READMODE, r16
  ldi r16, UART_HW_WRITEMODE_IDLE
  std Y+UART_HW_IFACE_OFFS_WRITEMODE, r16
  ret
; @end



; ---------------------------------------------------------------------------
; @routine UART_HW_Interface_SetReadBuffer @global
;
; @param Y pointer to interface data in SRAM
; @param r16 read buffer number
; @param X   pointer to read buffer
; @clobbers R17

UART_HW_Interface_SetReadBuffer:
  std Y+UART_HW_IFACE_OFFS_READBUFNUM, r16
  adiw xh:xl, 1
  std Y+UART_HW_IFACE_OFFS_READBUFPOS_LOW, xl
  std Y+UART_HW_IFACE_OFFS_READBUFPOS_HIGH, xh
  sbiw xh:xl, 1
  clr r17
  std Y+UART_HW_IFACE_OFFS_READBUFUSED, r17
  ldi r17, NET_BUFFERS_SIZE-1
  std Y+UART_HW_IFACE_OFFS_READBUFLEFT, r17
  ret
; @end



; ---------------------------------------------------------------------------
; @routine UART_HW_Interface_SetWriteBuffer @global
;
; @param Y pointer to interface data in SRAM
; @param r16 write buffer number
; @param X   pointer to write buffer
; @clobbers r17

UART_HW_Interface_SetWriteBuffer:
  std Y+UART_HW_IFACE_OFFS_WRITEBUFNUM, r16
  adiw xh:xl, 1
  std Y+UART_HW_IFACE_OFFS_WRITEBUFPOS_LOW, xl   ; begin of msg (dest addr byte)
  std Y+UART_HW_IFACE_OFFS_WRITEBUFPOS_HIGH, xh
  adiw xh:xl, 1                                  
  ld r17, X                                      ; payload length byte
  sbiw xh:xl, 2                                  ; back to start of buffer
  inc r17
  inc r17
  inc r17
  std Y+UART_HW_IFACE_OFFS_WRITEBUFUSED, r17
  std Y+UART_HW_IFACE_OFFS_WRITEBUFLEFT, r17
  ret
; @end