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// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/**********************************************************************
DALLAS DS2404
RTC + BACKUP RAM
**********************************************************************/
#ifndef MAME_MACHINE_DS2404_H
#define MAME_MACHINE_DS2404_H
#pragma once
class ds2404_device : public device_t, public device_nvram_interface
{
public:
// construction/destruction
ds2404_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock);
// inline configuration helpers
void ref_year(uint32_t year) { m_ref_year = year; }
void ref_month(uint8_t month) { m_ref_month = month; }
void ref_day(uint8_t day) { m_ref_day = day; }
/* 1-wire interface reset */
void _1w_reset_w(uint8_t data);
/* 3-wire interface reset */
void _3w_reset_w(uint8_t data);
uint8_t data_r();
void data_w(uint8_t data);
void clk_w(uint8_t data);
protected:
// device-level overrides
virtual void device_start() override;
virtual void device_reset() override { }
virtual void device_post_load() override { }
virtual void device_clock_changed() override { }
// device_nvram_interface overrides
virtual void nvram_default() override;
virtual bool nvram_read(util::read_stream &file) override;
virtual bool nvram_write(util::write_stream &file) override;
TIMER_CALLBACK_MEMBER(timer_tick);
private:
void rom_cmd(uint8_t cmd);
void cmd(uint8_t cmd);
uint8_t readmem();
void writemem(uint8_t value);
enum STATE
{
STATE_IDLE = 1, /* waiting for ROM command, in 1-wire mode */
STATE_COMMAND, /* waiting for memory command */
STATE_ADDRESS1, /* waiting for address bits 0-7 */
STATE_ADDRESS2, /* waiting for address bits 8-15 */
STATE_OFFSET, /* waiting for ending offset */
STATE_INIT_COMMAND,
STATE_READ_MEMORY, /* Read Memory command active */
STATE_WRITE_SCRATCHPAD, /* Write Scratchpad command active */
STATE_READ_SCRATCHPAD, /* Read Scratchpad command active */
STATE_COPY_SCRATCHPAD /* Copy Scratchpad command active */
};
emu_timer *m_tick_timer;
// configuration state
uint32_t m_ref_year;
uint8_t m_ref_month;
uint8_t m_ref_day;
uint16_t m_address;
uint16_t m_offset;
uint16_t m_end_offset;
uint8_t m_a1;
uint8_t m_a2;
uint8_t m_sram[512]; /* 4096 bits */
uint8_t m_ram[32]; /* scratchpad ram, 256 bits */
uint8_t m_rtc[5]; /* 40-bit RTC counter */
STATE m_state[8];
int m_state_ptr;
};
DECLARE_DEVICE_TYPE(DS2404, ds2404_device)
#endif // MAME_MACHINE_DS2404_H
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