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/* Copyright (c) 2009 Dmitry Xmelkov
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
* Neither the name of the copyright holders nor the names of
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. */
/* $Id: eewr_byte.S,v 1.1.2.3 2009/09/10 01:45:31 dmix Exp $ */
#ifndef __DOXYGEN
#include <avr/io.h>
#if E2END && __AVR_ARCH__ > 1
#include <avr/eeprom.h>
#include "asmdef.h"
#include "eedef.h"
ENTRY eeprom_write_byte
mov r18, r22
ENTRY eeprom_write_r18
#if __AVR_XMEGA__ /* -------------------------------------------- */
# ifndef CCP_IOREG_gc
# define CCP_IOREG_gc 0xD8 /* IO Register Protection */
# endif
# ifndef NVM_CMD_READ_EEPROM_gc
# define NVM_CMD_READ_EEPROM_gc 0x06
# endif
# ifndef NVM_CMD_LOAD_EEPROM_BUFFER_gc
# define NVM_CMD_LOAD_EEPROM_BUFFER_gc 0x33
# endif
# ifndef NVM_CMD_ERASE_WRITE_EEPROM_PAGE_gc
# define NVM_CMD_ERASE_WRITE_EEPROM_PAGE_gc 0x35
# endif
# ifndef NVM_CMD_ERASE_EEPROM_BUFFER_gc
# define NVM_CMD_ERASE_EEPROM_BUFFER_gc 0x36
# endif
; Prepare base address of NVM.
ldi ZL, lo8(NVM_BASE)
ldi ZH, hi8(NVM_BASE)
; Wait until NVM is not busy.
1: ldd r19, Z + NVM_STATUS - NVM_BASE
sbrc r19, NVM_NVMBUSY_bp
rjmp 1b
; Disable EEPROM mapping into data space.
ldd r19, Z + NVM_CTRLB - NVM_BASE
andi r19, ~NVM_EEMAPEN_bm
std Z + NVM_CTRLB - NVM_BASE, r19
; Check the clearance of EEPROM page buffer.
ldd r19, Z + NVM_STATUS - NVM_BASE
sbrs r19, NVM_EELOAD_bp
rjmp 3f ; erase is not required
; Note that we have only four clock cycles to write to the CCP
; protected register NVM_CTRLA, after writing to CCP. The 'ldi'
; instruction always takes one clock to execute and 'std' instruction takes
; two clock cycles. We fall within the four cycles that the CCP leaves
; us to write the command execution start bit to the NVM_CTRLA
; register. Note that r18 must be preserved until written to NVM_DATA0
; Issue EEPROM Buffer Erase:
ldi r19, NVM_CMD_ERASE_EEPROM_BUFFER_gc
std Z + NVM_CMD - NVM_BASE, r19
ldi r19, CCP_IOREG_gc
out CCP, r19
ldi r19, NVM_CMDEX_bm
std Z + NVM_CTRLA - NVM_BASE, r19
; Wait until NVM is not busy.
2: ldd r19, Z + NVM_STATUS - NVM_BASE
sbrc r19, NVM_NVMBUSY_bp
rjmp 2b
; Issue EEPROM Buffer Load command.
3: ldi r19, NVM_CMD_LOAD_EEPROM_BUFFER_gc
std Z + NVM_CMD - NVM_BASE, r19
std Z + NVM_ADDR0 - NVM_BASE, addr_lo
std Z + NVM_ADDR1 - NVM_BASE, addr_hi
std Z + NVM_ADDR2 - NVM_BASE, __zero_reg__
std Z + NVM_DATA0 - NVM_BASE, r18
; Issue EEPROM Erase & Write command.
ldi r18, NVM_CMD_ERASE_WRITE_EEPROM_PAGE_gc
std Z + NVM_CMD - NVM_BASE, r18
ldi r18, CCP_IOREG_gc
ldi r19, NVM_CMDEX_bm
out CCP, r18
std Z + NVM_CTRLA - NVM_BASE, r19
; Increment address.
adiw addr_lo, 1
ret
#else /* ---------------------------------------------------- */
1: sbic _SFR_IO_ADDR (EECR), EEWE
rjmp 1b
# if defined (EEPM0) && defined (EEPM1)
; Set programming mode: erase and write.
out _SFR_IO_ADDR (EECR), __zero_reg__
# elif defined (EEPM0) || defined (EEPM1)
# error /* Unknown EECR register. */
# endif
# ifdef EEARH
# if E2END > 0xFF
out _SFR_IO_ADDR (EEARH), addr_hi
# else
; This is for chips like ATmega48: the EEAR8 bit must be cleaned.
out _SFR_IO_ADDR (EEARH), __zero_reg__
# endif
# endif
out _SFR_IO_ADDR (EEARL), addr_lo
out _SFR_IO_ADDR (EEDR), r18
in __tmp_reg__, _SFR_IO_ADDR (SREG)
cli
sbi _SFR_IO_ADDR (EECR), EEMWE
sbi _SFR_IO_ADDR (EECR), EEWE
out _SFR_IO_ADDR (SREG), __tmp_reg__
adiw addr_lo, 1
ret
#endif /* ---------------------------------------------------- */
ENDFUNC
#endif /* E2END && __AVR_ARCH__ > 1 */
#endif /* !__DOXYGEN__ */
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