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(MESS) hd44780: added 4-bit interface mode. (nw)

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This commit is contained in:
Sandro Ronco 2013-01-19 19:47:24 +00:00
parent 3d2da02fe1
commit 11b5eef085
2 changed files with 92 additions and 27 deletions
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116
src/mess/video/hd44780.c
View File

@ -3,7 +3,6 @@
Hitachi HD44780 LCD controller
TODO:
- 4-bit mode
- 5x10 chars
- dump internal CGROM
@ -87,7 +86,8 @@ void hd44780_device::device_start()
save_item( NAME(m_blink));
save_item( NAME(m_ddram));
save_item( NAME(m_cgram));
save_item( NAME(m_nibble));
save_item( NAME(m_data_latch));
}
@ -115,6 +115,8 @@ void hd44780_device::device_reset()
m_char_size = 0;
m_disp_shift = 0;
m_blink = 0;
m_nibble = false;
m_data_latch = 0;
set_busy_flag(1520);
}
@ -223,34 +225,53 @@ UINT32 hd44780_device::screen_update(screen_device &screen, bitmap_ind16 &bitmap
WRITE8_MEMBER(hd44780_device::control_write)
{
if (BIT(data, 7)) // Set DDRAM Address
if (m_data_len == 0)
{
m_nibble = !m_nibble;
if (m_nibble)
{
m_data_latch = data & 0xf0;
return;
}
else
{
m_data_latch |= ((data>>4) & 0x0f);
}
}
else
{
m_data_latch = data;
}
if (BIT(m_data_latch, 7)) // Set DDRAM Address
{
m_ac_mode = 0;
m_ac = data & 0x7f;
m_ac = m_data_latch & 0x7f;
m_cursor_pos = m_ac;
set_busy_flag(37);
}
else if (BIT(data, 6)) // Set CGRAM Address
else if (BIT(m_data_latch, 6)) // Set CGRAM Address
{
m_ac_mode = 1;
m_ac = data & 0x3f;
m_ac = m_data_latch & 0x3f;
set_busy_flag(37);
}
else if (BIT(data, 5)) // Function Set
else if (BIT(m_data_latch, 5)) // Function Set
{
// datasheet says you can't change char size after first function set without altering 4/8 bit mode
if (BIT(data, 4) != m_data_len)
m_char_size = BIT(data, 2);
if (BIT(m_data_latch, 4) != m_data_len)
m_char_size = BIT(m_data_latch, 2);
m_data_len = BIT(data, 4);
m_num_line = BIT(data, 3);
m_data_len = BIT(m_data_latch, 4);
m_num_line = BIT(m_data_latch, 3);
set_busy_flag(37);
}
else if (BIT(data, 4)) // Cursor or display shift
else if (BIT(m_data_latch, 4)) // Cursor or display shift
{
UINT8 direct = (BIT(data, 2)) ? +1 : -1;
UINT8 direct = (BIT(m_data_latch, 2)) ? +1 : -1;
if (BIT(data, 3))
if (BIT(m_data_latch, 3))
m_disp_shift += direct;
else
{
@ -260,23 +281,23 @@ WRITE8_MEMBER(hd44780_device::control_write)
set_busy_flag(37);
}
else if (BIT(data, 3)) // Display on/off Control
else if (BIT(m_data_latch, 3)) // Display on/off Control
{
m_display_on = BIT(data, 2);
m_cursor_on = BIT(data, 1);
m_blink_on = BIT(data, 0);
m_display_on = BIT(m_data_latch, 2);
m_cursor_on = BIT(m_data_latch, 1);
m_blink_on = BIT(m_data_latch, 0);
set_busy_flag(37);
}
else if (BIT(data, 2)) // Entry Mode set
else if (BIT(m_data_latch, 2)) // Entry Mode set
{
m_direction = (BIT(data, 1)) ? +1 : -1;
m_direction = (BIT(m_data_latch, 1)) ? +1 : -1;
m_shift_on = BIT(data, 0);
m_shift_on = BIT(m_data_latch, 0);
set_busy_flag(37);
}
else if (BIT(data, 1)) // return home
else if (BIT(m_data_latch, 1)) // return home
{
m_ac = 0;
m_cursor_pos = 0;
@ -285,7 +306,7 @@ WRITE8_MEMBER(hd44780_device::control_write)
m_disp_shift = 0;
set_busy_flag(1520);
}
else if (BIT(data, 0)) // clear display
else if (BIT(m_data_latch, 0)) // clear display
{
m_ac = 0;
m_cursor_pos = 0;
@ -299,7 +320,19 @@ WRITE8_MEMBER(hd44780_device::control_write)
READ8_MEMBER(hd44780_device::control_read)
{
return (m_busy_flag << 7) | (m_ac & 0x7f);
if (m_data_len == 0)
{
m_nibble = !m_nibble;
if (m_nibble)
return (m_busy_flag << 7) | (m_ac & 0x70);
else
return (m_ac<<4) & 0xf0;
}
else
{
return (m_busy_flag << 7) | (m_ac & 0x7f);
}
}
void hd44780_device::update_ac(void) // m_data_bus_flag was left as global so old savestates will work
@ -324,10 +357,29 @@ WRITE8_MEMBER(hd44780_device::data_write)
return;
}
if (m_ac_mode == 0)
m_ddram[m_ac] = data;
if (m_data_len == 0)
{
m_nibble = !m_nibble;
if (m_nibble)
{
m_data_latch = data & 0xf0;
return;
}
else
{
m_data_latch |= ((data>>4) & 0x0f);
}
}
else
m_cgram[m_ac] = data;
{
m_data_latch = data;
}
if (m_ac_mode == 0)
m_ddram[m_ac] = m_data_latch;
else
m_cgram[m_ac] = m_data_latch;
m_data_bus_flag = 1;
update_ac();
@ -343,6 +395,16 @@ READ8_MEMBER(hd44780_device::data_read)
else
data = m_cgram[m_ac];
if (m_data_len == 0)
{
m_nibble = !m_nibble;
if (m_nibble)
return data & 0xf0;
else
data = (data<<4) & 0xf0;
}
m_data_bus_flag = 2;
update_ac();

3
src/mess/video/hd44780.h
View File

@ -96,6 +96,9 @@ protected:
UINT8 m_char_size; //char size 5x8 or 5x10
UINT8 m_blink;
bool m_nibble;
UINT8 m_data_latch;
};
// device type definition