diff options
author | Nigel Barnes <Pernod70@users.noreply.github.com> | 2019-11-22 23:15:54 +0000 |
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committer | Nigel Barnes <Pernod70@users.noreply.github.com> | 2019-11-22 23:18:04 +0000 |
commit | 50d394f973fbe47523abc9b5bb3238cf0d705889 (patch) | |
tree | 44885949f3b988c689a168932100a6a24aea0046 /src/devices/bus | |
parent | ed3fb56b47940aecbe7961b247861f878aa50127 (diff) |
bml3: Added Hitachi Real Time Clock card [Russell Bull]
Diffstat (limited to 'src/devices/bus')
-rw-r--r-- | src/devices/bus/bml3/bml3rtc.cpp | 104 | ||||
-rw-r--r-- | src/devices/bus/bml3/bml3rtc.h | 52 |
2 files changed, 156 insertions, 0 deletions
diff --git a/src/devices/bus/bml3/bml3rtc.cpp b/src/devices/bus/bml3/bml3rtc.cpp new file mode 100644 index 00000000000..baaba60a22c --- /dev/null +++ b/src/devices/bus/bml3/bml3rtc.cpp @@ -0,0 +1,104 @@ +// license:GPL-2.0+ +// copyright-holders:Russell Bull +/********************************************************************* + + bml3rtc.cpp + + Hitachi RTC card for the MB-6890 + + I cannot find any reference to the original Hitachi board that + had this feature, but I was given a schematic back in the 1980's + and I designed a board that included the circuitry. + The standard ROM supported this battery-backed RTC and detects + it's presence on start up. + +*********************************************************************/ + +#include "emu.h" +#include "bml3rtc.h" + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +DEFINE_DEVICE_TYPE(BML3BUS_RTC, bml3bus_rtc_device, "bml3rtc", "Hitachi Real Time Clock Card") + + +//------------------------------------------------- +// device_add_mconfig - add device configuration +//------------------------------------------------- + +void bml3bus_rtc_device::device_add_mconfig(machine_config &config) +{ + MSM5832(config, m_rtc, 32.768_kHz_XTAL); +} + + +READ8_MEMBER(bml3bus_rtc_device::bml3_rtc_r) +{ + uint8_t data = 0x00; + + if (offset == 2) // read @ 0xff3a + { + if (BIT(m_addr_latch, 7)) //bit 7 is the !write buffer enable + { + data = m_rtc->data_r(); + } + else + { + data = m_data_latch; //the Hitachi ROM code detects RTC presence by reading back what it wrote to the data latch + } + } + return data | 0xf0; // return low nibble only +} + +WRITE8_MEMBER(bml3bus_rtc_device::bml3_rtc_w) +{ + switch (offset) + { + case 0: // addr latch @ 0xff38 + m_rtc->cs_w(1); //always selected + m_rtc->write_w(BIT(data, 6)); + m_rtc->read_w(BIT(data, 7)); + m_rtc->address_w(data & 0x0f); + + m_addr_latch = data; + break; + + case 1: // data latch @ 0xff39 + m_rtc->hold_w(BIT(data, 6)); + + if (BIT(m_addr_latch, 6)) + { + m_rtc->data_w(data & 0x0f); + } + + m_data_latch = data; + break; + } +} +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +bml3bus_rtc_device::bml3bus_rtc_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : device_t(mconfig, BML3BUS_RTC, tag, owner, clock) + , device_bml3bus_card_interface(mconfig, *this) + , m_rtc(*this, "rtc") +{ +} + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void bml3bus_rtc_device::device_start() +{ + // install into memory + address_space &space_prg = space(); + space_prg.install_readwrite_handler(0xff38, 0xff3a, read8_delegate(*this, FUNC(bml3bus_rtc_device::bml3_rtc_r)), write8_delegate(*this, FUNC(bml3bus_rtc_device::bml3_rtc_w))); + + m_addr_latch = 0; + m_data_latch = 0; +} diff --git a/src/devices/bus/bml3/bml3rtc.h b/src/devices/bus/bml3/bml3rtc.h new file mode 100644 index 00000000000..2adb9870804 --- /dev/null +++ b/src/devices/bus/bml3/bml3rtc.h @@ -0,0 +1,52 @@ +// license:GPL-2.0+ +// copyright-holders:Russell Bull +/********************************************************************* + + bml3rtc.h + + Hitachi RTC card for the MB-6890 + +*********************************************************************/ + +#ifndef MAME_BUS_BML3_BML3RTC_H +#define MAME_BUS_BML3_BML3RTC_H + +#pragma once + +#include "bml3bus.h" +#include "machine/msm5832.h" + + +//************************************************************************** +// TYPE DEFINITIONS +//************************************************************************** + +class bml3bus_rtc_device: + public device_t, + public device_bml3bus_card_interface +{ +public: + // construction/destruction + bml3bus_rtc_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock); + + DECLARE_READ8_MEMBER(bml3_rtc_r); + DECLARE_WRITE8_MEMBER(bml3_rtc_w); + +protected: + // device-level overrides + virtual void device_start() override; + + // optional information overrides + virtual void device_add_mconfig(machine_config &config) override; + +private: + required_device<msm5832_device> m_rtc; + + uint8_t m_addr_latch; + uint8_t m_data_latch; +}; + +// device type definition +DECLARE_DEVICE_TYPE(BML3BUS_RTC, bml3bus_rtc_device) + +#endif // MAME_BUS_BML3_BML3RTC_H |