// 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, uint32_t 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 */
DECLARE_WRITE8_MEMBER(ds2404_1w_reset_w);
/* 3-wire interface reset */
DECLARE_WRITE8_MEMBER(ds2404_3w_reset_w);
DECLARE_READ8_MEMBER(ds2404_data_r);
DECLARE_WRITE8_MEMBER(ds2404_data_w);
DECLARE_WRITE8_MEMBER(ds2404_clk_w);
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 void nvram_read(emu_file &file) override;
virtual void nvram_write(emu_file &file) override;
virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) override;
private:
void ds2404_rom_cmd(uint8_t cmd);
void ds2404_cmd(uint8_t cmd);
uint8_t ds2404_readmem();
void ds2404_writemem(uint8_t value);
enum DS2404_STATE
{
DS2404_STATE_IDLE = 1, /* waiting for ROM command, in 1-wire mode */
DS2404_STATE_COMMAND, /* waiting for memory command */
DS2404_STATE_ADDRESS1, /* waiting for address bits 0-7 */
DS2404_STATE_ADDRESS2, /* waiting for address bits 8-15 */
DS2404_STATE_OFFSET, /* waiting for ending offset */
DS2404_STATE_INIT_COMMAND,
DS2404_STATE_READ_MEMORY, /* Read Memory command active */
DS2404_STATE_WRITE_SCRATCHPAD, /* Write Scratchpad command active */
DS2404_STATE_READ_SCRATCHPAD, /* Read Scratchpad command active */
DS2404_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 */
DS2404_STATE m_state[8];
int m_state_ptr;
};
DECLARE_DEVICE_TYPE(DS2404, ds2404_device)
#endif // MAME_MACHINE_DS2404_H