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author Mike <mike.harris@gmail.com>2019-06-19 16:55:46 -0700
committer ajrhacker <ajrhacker@users.noreply.github.com>2019-06-19 19:55:46 -0400
commit2e0f4af6ee693fb6f40183bc60ef16db826c8780 (patch)
tree2f3a9fd60d4bc5706f68e0a4cddb62dad65df65d /src/devices/bus/ss50
parent492a9e1b48c47e8c1299fedf2efd5612b580f5d2 (diff)
Pia6821 improvements (#5254)
* 6821pia: fix method names in comments * zwackery: Remove PIA port A z_mask setting. This would only be relevant if the PIA was read while in output mode. These are inputs, and only read in input mode, so z_mask is not relevant. * thomson: move pia pullup resistors from z_mask to read handler. * 6821pia: remove unused set_port_a_z_mask calls. * dgn_beta: move pia pullup resistors from z_mask to read handler. * mpu3: Don't invert the VFD power on reset line. It doesn't go through an inverter. I believe this was done to work around a bug in the PIA port A implementation. * pia6821: remove m_port_a_z_mask variable. * 6821pia: For port A reads, only use the DDR for reading pins unless. Provide an override option when a device depends on slightly undefined behavior of an external device driving the pins and changing the value read. One board seems to need this (coinmstr). I don't have the schematics, but it seems it uses this to check its meter operation.
Diffstat (limited to 'src/devices/bus/ss50')
-rw-r--r--src/devices/bus/ss50/mpc.cpp2
1 files changed, 1 insertions, 1 deletions
diff --git a/src/devices/bus/ss50/mpc.cpp b/src/devices/bus/ss50/mpc.cpp
index ba05d80e8e3..8563a289202 100644
--- a/src/devices/bus/ss50/mpc.cpp
+++ b/src/devices/bus/ss50/mpc.cpp
@@ -136,7 +136,7 @@ void ss50_mpc_device::device_start()
WRITE_LINE_MEMBER(ss50_mpc_device::serial_input_w)
{
- m_pia->set_a_input(state << 7, 0x7f);
+ m_pia->set_a_input(state << 7);
m_loopback->in_w<0>(state);
}