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Diffstat (limited to 'src/devices/video/md4330b.cpp')
-rw-r--r-- | src/devices/video/md4330b.cpp | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/src/devices/video/md4330b.cpp b/src/devices/video/md4330b.cpp new file mode 100644 index 00000000000..de3b2e49c4a --- /dev/null +++ b/src/devices/video/md4330b.cpp @@ -0,0 +1,104 @@ +// license:BSD-3-Clause +// copyright-holders:hap +/* + +Mitel MD4330B / MD4332B LCD Driver + +It's a simple shift register CMOS LCD driver. +'30 has 30 segments, '32 has 32. The "C" versions are ceramic chips, the "E" are epoxy. + +TODO: +- RST pin (asynchronous on MD4332B) + +*/ + +#include "emu.h" +#include "video/md4330b.h" + + +DEFINE_DEVICE_TYPE(MD4330B, md4330b_device, "md4330b", "Mitel MD4330B LCD Driver") +DEFINE_DEVICE_TYPE(MD4332B, md4332b_device, "md4332b", "Mitel MD4332B LCD Driver") + +//------------------------------------------------- +// constructor +//------------------------------------------------- + +md4330b_device::md4330b_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, u8 qmax) : + device_t(mconfig, type, tag, owner, clock), + m_qmax(qmax), m_write_q(*this), m_write_do(*this) +{ } + +md4330b_device::md4330b_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : + md4330b_device(mconfig, MD4330B, tag, owner, clock, 30) +{ } + +md4332b_device::md4332b_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) : + md4330b_device(mconfig, MD4332B, tag, owner, clock, 32) +{ } + + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void md4330b_device::device_start() +{ + // resolve callbacks + m_write_q.resolve_safe(); + m_write_do.resolve_safe(); + + // zerofill + m_shift = 0; + m_clk = 0; + m_di = 0; + m_do = 0; + m_rst = 0; + m_tc = 0; + + // register for savestates + save_item(NAME(m_shift)); + save_item(NAME(m_clk)); + save_item(NAME(m_di)); + save_item(NAME(m_do)); + save_item(NAME(m_rst)); + save_item(NAME(m_tc)); +} + + +//------------------------------------------------- +// handlers +//------------------------------------------------- + +void md4330b_device::update_q() +{ + u32 out = m_shift; + if (m_tc) + out = ~out; + out &= (1 << m_qmax) - 1; + + m_write_q(0, out); +} + +WRITE_LINE_MEMBER(md4330b_device::clk_w) +{ + state = (state) ? 1 : 0; + + // shift on rising edge + if (state && !m_clk) + { + // DO pin follows carry out + m_do = (m_rst) ? 0 : BIT(m_shift, m_qmax-1); + + if (m_rst) + m_shift = 0; + else + m_shift = (m_shift << 1) | m_di; + + // output + update_q(); + m_write_do(m_do); + } + + m_clk = state; +} |