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mm74c922: data output pins are clocked the same time as DA pin

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This commit is contained in:
hap 2020-07-17 21:36:40 +02:00
parent 33fbb85d59
commit 65a2745af0
3 changed files with 22 additions and 13 deletions
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24
src/devices/machine/mm74c922.cpp
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@ -34,15 +34,15 @@ DEFINE_DEVICE_TYPE(MM74C923, mm74c923_device, "mm74c923", "MM74C923 20-Key Encod
mm74c922_device::mm74c922_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock, int max_y) :
device_t(mconfig, type, tag, owner, clock),
m_write_da(*this),
m_read_x(*this),
m_write_da(*this), m_read_x(*this),
m_cap_osc(0), m_cap_debounce(0),
m_max_y(max_y),
m_inhibit(false),
m_x(0),
m_y(0), m_data(0),
m_da(false),
m_next_da(false), m_scan_timer(nullptr)
m_y(0),
m_data(0), m_next_data(0),
m_da(false), m_next_da(false),
m_scan_timer(nullptr)
{
}
@ -79,6 +79,7 @@ void mm74c922_device::device_start()
save_item(NAME(m_x));
save_item(NAME(m_y));
save_item(NAME(m_data));
save_item(NAME(m_next_data));
save_item(NAME(m_da));
save_item(NAME(m_next_da));
}
@ -123,6 +124,12 @@ void mm74c922_device::change_output_lines()
// active high output
m_write_da(m_da ? 1 : 0);
}
// clock data latches
if (m_next_data != m_data)
{
m_data = m_next_data;
}
}
@ -156,7 +163,7 @@ void mm74c922_device::detect_keypress()
// key released
m_inhibit = false;
m_next_da = false;
m_data = 0xff; // high-Z
m_next_data = (1 << m_max_y) - 1; // high-Z
LOG("MM74C922 Key Released\n");
}
@ -172,10 +179,9 @@ void mm74c922_device::detect_keypress()
m_next_da = true;
m_y = y;
m_data = (y << 2) | m_x;
m_next_data = (y << 2) | m_x;
LOG("MM74C922 Key Depressed: X %u Y %u = %02x\n", m_x, y, m_data);
return;
LOG("MM74C922 Key Depressed: X %u Y %u = %02x\n", m_x, y, m_next_data);
}
}
}

1
src/devices/machine/mm74c922.h
View File

@ -86,6 +86,7 @@ private:
int m_y; // latched row
uint8_t m_data; // data latch
uint8_t m_next_data; // next value of data latch
bool m_da; // data available flag
bool m_next_da; // next value of data available flag

10
src/mame/drivers/saitek_intchess.cpp
View File

@ -18,7 +18,8 @@ Hardware notes:
- 4-digit 7seg display
TODO:
- remove nmistate workaround when 6502 NMI is fixed
- 6502 CPU core NMI isn't working properly at the moment, it acts like a hold_line,
m_nmistate can be removed once that is fixed
- colors are estimated from photos (black and white are obvious, but the green
and cyan are not standard 0x00ff00 / 0x00ffff)
- video timing is unknown, sprite offsets are estimated from photos
@ -100,6 +101,7 @@ private:
u8 m_select = 0;
u8 m_7seg_data = 0;
bool m_nmistate = false;
};
void intchess_state::machine_start()
@ -107,6 +109,7 @@ void intchess_state::machine_start()
// register for savestates
save_item(NAME(m_select));
save_item(NAME(m_7seg_data));
save_item(NAME(m_nmistate));
}
INPUT_CHANGED_MEMBER(intchess_state::reset_button)
@ -205,13 +208,12 @@ u8 intchess_state::control_r()
TIMER_DEVICE_CALLBACK_MEMBER(intchess_state::cass_input)
{
// cassette input is tied to NMI
static bool nmistate = false;
bool state = ((m_cass->get_state() & CASSETTE_MASK_UISTATE) == CASSETTE_PLAY) && (m_cass->input() < -0.04);
if (state != nmistate)
if (state != m_nmistate)
{
m_maincpu->set_input_line(INPUT_LINE_NMI, state ? ASSERT_LINE : CLEAR_LINE);
nmistate = state;
m_nmistate = state;
}
}