summaryrefslogtreecommitdiffstatshomepage
path: root/src/devices/bus/mackbd/pluskbd.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'src/devices/bus/mackbd/pluskbd.cpp')
-rw-r--r--src/devices/bus/mackbd/pluskbd.cpp7
1 files changed, 7 insertions, 0 deletions
diff --git a/src/devices/bus/mackbd/pluskbd.cpp b/src/devices/bus/mackbd/pluskbd.cpp
index 41da3f01f43..bbdd1c5d6d8 100644
--- a/src/devices/bus/mackbd/pluskbd.cpp
+++ b/src/devices/bus/mackbd/pluskbd.cpp
@@ -129,6 +129,7 @@ protected:
virtual void device_add_mconfig(machine_config &config) override
{
I8048(config, m_mpu, 6_MHz_XTAL); // NEC 8048HC517 341-0332-A with ceramic resonator
+ m_mpu->set_addrmap(AS_IO, &m0110a_device::mpu_io);
m_mpu->p1_out_cb().set(FUNC(m0110a_device::p1_w));
m_mpu->p2_in_cb().set_ioport("P2");
m_mpu->p2_out_cb().set(FUNC(m0110a_device::p2_w));
@@ -191,6 +192,12 @@ private:
return result;
}
+ void mpu_io(address_map &map)
+ {
+ // MPU writes 0xff to these addresses before reading columns to ensure the bus pins aren't pulled down
+ map(0x2a, 0x33).nopw();
+ }
+
TIMER_CALLBACK_MEMBER(update_host_data)
{
if (bool(param) != bool(m_host_data_in))