// license:BSD-3-Clause // copyright-holders:hap /* National Semiconductor MM5445 series VFD Driver TODO: - brightness control input pin (sets output voltage level) */ #include "emu.h" #include "video/mm5445.h" DEFINE_DEVICE_TYPE(MM5445, mm5445_device, "mm5445", "MM5445 VFD Driver") DEFINE_DEVICE_TYPE(MM5446, mm5446_device, "mm5446", "MM5446 VFD Driver") DEFINE_DEVICE_TYPE(MM5447, mm5447_device, "mm5447", "MM5447 VFD Driver") DEFINE_DEVICE_TYPE(MM5448, mm5448_device, "mm5448", "MM5448 VFD Driver") //------------------------------------------------- // constructor //------------------------------------------------- mm5445_device::mm5445_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, u8 outpins) : device_t(mconfig, type, tag, owner, clock), m_outmask((u64(1) << outpins) - 1), m_write_output(*this) { } mm5445_device::mm5445_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : mm5445_device(mconfig, MM5445, tag, owner, clock, 33) { } mm5446_device::mm5446_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : mm5445_device(mconfig, MM5446, tag, owner, clock, 34) { } mm5447_device::mm5447_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : mm5445_device(mconfig, MM5447, tag, owner, clock, 34) { } mm5448_device::mm5448_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : mm5445_device(mconfig, MM5448, tag, owner, clock, 35) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void mm5445_device::device_start() { // resolve callbacks m_write_output.resolve_safe(); // zerofill m_clk = 0; m_enable = 0; m_data = 0; m_shiftreg = 0; m_shiftcount = 0; // register for savestates save_item(NAME(m_clk)); save_item(NAME(m_enable)); save_item(NAME(m_data)); save_item(NAME(m_shiftreg)); save_item(NAME(m_shiftcount)); } //------------------------------------------------- // handlers //------------------------------------------------- WRITE_LINE_MEMBER(mm5445_device::clock_w) { state = (state) ? 1 : 0; bool rise = state && !m_clk; m_clk = state; // clock on rising edge if (rise) { u64 data_in = u64(m_data & ~m_enable) << 34; u64 lead_in = ~m_shiftreg & data_in; m_shiftreg = (m_shiftreg & ((u64(1) << 34) - 1)) | data_in; // leading 1 triggers shift start if (m_shiftcount == 0 && !lead_in) return; // output on 35th clock if (m_shiftcount == 35) { m_shiftcount = 0; m_write_output(0, m_shiftreg & m_outmask, ~u64(0)); } else { m_shiftreg >>= 1; m_shiftcount++; } } }