diff options
author | 2017-05-27 18:44:23 +1000 | |
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committer | 2017-05-27 18:44:23 +1000 | |
commit | 2d4ba2471d86555562870973bd456c8dc2581d33 (patch) | |
tree | 1e9ba23de32b657e045e3f116fea17fba96d54c4 /scripts/src | |
parent | 95b2aa3dc30776e08c77f1707d5ce8d5af90c1b7 (diff) |
netlist: add a crude TTL schmitt trigger model and hook up in 1B11142
sound board, completing the tromba circuit
(nw) I'm not sure whether the model works properly or not, but in the
circuit where it's used, I don't think it can work properly with the
current TTL output model. A capacitor is charged by the Q output of a
74LS74 flipflop (U3A) until the voltage passes the Schmitt trigger's
threshold, causing it to reset the flipflop. However, the positive
trigger voltage of the Schmitt trigger is 1.6V, but our TTL output model
has a high output voltage of 1.0V (see nl_base.cpp:89). I realise the
simplified model of TTL logic with high impedance inputs and outputs
behaving as though thery're loaded is convenient and fast to simulate,
but it's not detailed enough for applications like this where
7400-series chips are used in analog circuitry. This is what held me up
last time I tried adding a netlist for this sound board.
Diffstat (limited to 'scripts/src')
-rw-r--r-- | scripts/src/netlist.lua | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/scripts/src/netlist.lua b/scripts/src/netlist.lua index d8238e49246..c15e7bc89fd 100644 --- a/scripts/src/netlist.lua +++ b/scripts/src/netlist.lua @@ -192,6 +192,8 @@ project "netlist" MAME_DIR .. "src/lib/netlist/devices/nld_r2r_dac.h", MAME_DIR .. "src/lib/netlist/devices/nld_tristate.cpp", MAME_DIR .. "src/lib/netlist/devices/nld_tristate.h", + MAME_DIR .. "src/lib/netlist/devices/nld_schmitt.cpp", + MAME_DIR .. "src/lib/netlist/devices/nld_schmitt.h", MAME_DIR .. "src/lib/netlist/devices/nld_legacy.cpp", MAME_DIR .. "src/lib/netlist/devices/nld_legacy.h", MAME_DIR .. "src/lib/netlist/devices/net_lib.cpp", |