eeprom.c

/* Copyright (C) 2015 Baruch Even
 *
 * This file is part of the B3603 alternative firmware.
 *
 *  B3603 alternative firmware is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  B3603 alternative firmware is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with B3603 alternative firmware.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "eeprom.h"
#include "stm8s.h"

static uint8_t eeprom_unlock_data(void)
{
	FLASH_DUKR = 0xAE; // Enable the flash data writing
	FLASH_DUKR = 0x56;

	return (FLASH_IAPSR & FLASH_IAPSR_DUL); // True if device unlocked
}

inline void eeprom_lock(void)
{
	FLASH_IAPSR &= ~FLASH_IAPSR_DUL;
}

uint8_t eeprom_set_afr0(void)
{
	uint8_t sr;
	uint16_t timeout = 0xFFFF;

	if (!eeprom_unlock_data())
		return 0;

	FLASH_CR2 = FLASH_CR2_OPT;// Set the OPT bit
	FLASH_NCR2 = ~FLASH_NCR2_NOPT; // Remove the NOPT bit

	OPT2 = 1;
	NOPT2 = 0xFE;
	for (timeout = 0xFFFF; timeout > 0; timeout--) {
		sr = FLASH_IAPSR;
		if (sr & FLASH_IAPSR_EOP)
			break;
	}

	if (sr & FLASH_IAPSR_WR_PG_DIS)
		timeout = 0; // This will report failure

	FLASH_CR2 &= FLASH_CR2_OPT;
	FLASH_NCR2 |= FLASH_NCR2_NOPT;
	eeprom_lock();
	return (timeout > 0) && (OPT2 & 1);
}

uint8_t eeprom_save_data(uint8_t *dst, uint8_t *src, uint8_t len)
{
	uint16_t timeout;
	uint8_t sr;

	if (!eeprom_unlock_data())
		return 0;

	for (; len > 0; len--, dst++, src++) {
		*dst = *src;
		IWDG_KR = 0xAA; // Reset the counter
	}

	for (timeout = 0xFFFF; timeout > 0; timeout--) {
		IWDG_KR = 0xAA; // Reset the counter
		sr = FLASH_IAPSR;
		if (sr & FLASH_IAPSR_EOP)
			break;
	}

	if (sr & FLASH_IAPSR_WR_PG_DIS)
		timeout = 0; // This will report failure

	eeprom_lock();
	return (timeout > 0);
}