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Diffstat (limited to 'src/devices/cpu/m6502/m5074x.cpp')
-rw-r--r--src/devices/cpu/m6502/m5074x.cpp31
1 files changed, 16 insertions, 15 deletions
diff --git a/src/devices/cpu/m6502/m5074x.cpp b/src/devices/cpu/m6502/m5074x.cpp
index 46e6fffc9ae..5df0e863a0c 100644
--- a/src/devices/cpu/m6502/m5074x.cpp
+++ b/src/devices/cpu/m6502/m5074x.cpp
@@ -57,6 +57,7 @@ m5074x_device::m5074x_device(const machine_config &mconfig, device_type type, co
m_tmrxlatch(0),
m_last_all_ints(0)
{
+ std::fill(std::begin(m_pullups), std::end(m_pullups), 0);
}
//-------------------------------------------------
@@ -315,7 +316,7 @@ uint8_t m5074x_device::ports_r(offs_t offset)
return m_ddrs[3];
case 0xa:
- return read_port(4);
+ return read_port(4) & 0x0f;
case 0xb:
return m_ddrs[4];
@@ -329,53 +330,53 @@ void m5074x_device::ports_w(offs_t offset, uint8_t data)
switch (offset)
{
case 0: // p0
- send_port(0, data & m_ddrs[0]);
+ send_port(0, (data & m_ddrs[0]) | (m_pullups[0] & ~m_ddrs[0]));
m_ports[0] = data;
break;
case 1: // p0 ddr
- send_port(0, m_ports[0] & data);
+ send_port(0, (m_ports[0] & data) | (m_pullups[0] & ~data));
m_ddrs[0] = data;
break;
case 2: // p1
- send_port(1, data & m_ddrs[1]);
+ send_port(1, (data & m_ddrs[1]) | (m_pullups[1] & ~m_ddrs[1]));
m_ports[1] = data;
break;
case 3: // p1 ddr
- send_port(1, m_ports[1] & data);
+ send_port(1, (m_ports[1] & data) | (m_pullups[1] & ~data));
m_ddrs[1] = data;
break;
case 4: // p2
- send_port(2, data & m_ddrs[2]);
+ send_port(2, (data & m_ddrs[2]) | (m_pullups[2] & ~m_ddrs[2]));
m_ports[2] = data;
break;
case 5: // p2 ddr
- send_port(2, m_ports[2] & data);
+ send_port(2, (m_ports[2] & data) | (m_pullups[2] & ~data));
m_ddrs[2] = data;
break;
case 8: // p3
- send_port(3, data & m_ddrs[3]);
+ send_port(3, (data & m_ddrs[3]) | (m_pullups[3] & ~m_ddrs[3]));
m_ports[3] = data;
break;
case 9: // p3 ddr
- send_port(3, m_ports[3] & data);
+ send_port(3, (m_ports[3] & data) | (m_pullups[3] & ~data));
m_ddrs[3] = data;
break;
- case 0xa: // p4
- send_port(4, data & m_ddrs[4]);
- m_ports[4] = data;
+ case 0xa: // p4 (4-bit open drain)
+ send_port(4, (data & m_ddrs[4] & 0x0f) | (m_pullups[4] & ~m_ddrs[4]));
+ m_ports[4] = data & 0x0f;
break;
case 0xb: // p4 ddr
- send_port(4, m_ports[4] & data);
- m_ddrs[4] = data;
+ send_port(4, (m_ports[4] & data & 0x0f) | (m_pullups[4] & ~data));
+ m_ddrs[4] = data & 0x0f;
break;
}
}
@@ -496,7 +497,7 @@ void m50753_device::m50753_map(address_map &map)
map(0x00e0, 0x00eb).rw(FUNC(m50753_device::ports_r), FUNC(m50753_device::ports_w));
map(0x00ee, 0x00ee).r(FUNC(m50753_device::in_r));
map(0x00ef, 0x00ef).r(FUNC(m50753_device::ad_r));
- map(0x00f2, 0x00f2).w(FUNC(m50753_device::ad_start_w));
+ map(0x00f2, 0x00f2).nopr().w(FUNC(m50753_device::ad_start_w));
map(0x00f3, 0x00f3).rw(FUNC(m50753_device::ad_control_r), FUNC(m50753_device::ad_control_w));
map(0x00f5, 0x00f5).rw(FUNC(m50753_device::pwm_control_r), FUNC(m50753_device::pwm_control_w));
map(0x00f9, 0x00ff).rw(FUNC(m50753_device::tmrirq_r), FUNC(m50753_device::tmrirq_w));