Set pitch for first Ch 3 special mode operator using MIDI channel 11.

src/midi.c

@@ -5,6 +5,7 @@
 #include "memory.h"
 #include "midi_fm.h"
 #include "midi_psg.h"
+#include "midi_fm_sm.h"
 #include "midi_sender.h"
 #include "synth.h"
 #include "ui_fm.h"
@@ -43,6 +44,10 @@ static const VTable FM_VTable = { midi_fm_note_on, midi_fm_note_off,
     midi_fm_channel_volume, midi_fm_pitch_bend, midi_fm_program,
     midi_fm_all_notes_off, midi_fm_pan };
 
+static const VTable SpecialMode_VTable = { midi_fm_sm_note_on, midi_fm_sm_note_off,
+    midi_fm_sm_channel_volume, midi_fm_sm_pitch_bend, midi_fm_sm_program,
+    midi_fm_sm_all_notes_off, midi_fm_sm_pan };
+
 static MappingMode mappingModePref;
 static MidiChannel midiChannels[MIDI_CHANNELS];
 static bool dynamicMode;
@@ -74,9 +79,18 @@ static void initMidiChannel(u8 midiChan)
 static void initDeviceChannel(u8 devChan)
 {
     DeviceChannel* chan = &deviceChannels[devChan];
-    bool isFm = devChan < DEV_CHAN_MIN_PSG;
-    chan->number = isFm ? devChan : devChan - DEV_CHAN_MIN_PSG;
-    chan->ops = isFm ? &FM_VTable : &PSG_VTable;
+
+    if(devChan <= DEV_CHAN_MAX_FM) {
+        chan->number = devChan;
+        chan->ops = &FM_VTable;
+    } else if(devChan <= DEV_CHAN_MAX_PSG) {
+        chan->number = devChan - DEV_CHAN_MIN_PSG;
+        chan->ops = &PSG_VTable;
+    } else {
+        chan->number = devChan - DEV_CHAN_MIN_SPECIAL_MODE;
+        chan->ops = &SpecialMode_VTable;
+    }
+
     chan->noteOn = false;
     chan->midiChannel = devChan;
     chan->pitch = 0;

src/midi.h

@@ -17,13 +17,15 @@
 #define PSG_NOISE_CHAN 3
 #define GENERAL_MIDI_PERCUSSION_CHANNEL 9
 
-#define DEV_CHANS 10
+#define DEV_CHANS 11
 #define DEV_CHAN_MIN_FM 0
 #define DEV_CHAN_MAX_FM 5
 #define DEV_CHAN_MIN_PSG 6
 #define DEV_CHAN_MAX_TONE_PSG 8
 #define DEV_CHAN_PSG_NOISE 9
 #define DEV_CHAN_MAX_PSG 9
+#define DEV_CHAN_MIN_SPECIAL_MODE 11
+#define DEV_CHAN_MAX_SPECIAL_MODE 11
 
 #define CC_DATA_ENTRY_MSB 6
 #define CC_VOLUME 7

src/midi_fm_sm.c

@@ -0,0 +1,49 @@
+#include "midi_fm_sm.h"
+#include "midi_fm.h"
+
+static const u8 SEMITONES = 12;
+static const u16 FREQS[] = {
+    607, // B
+    644, 681, 722, 765, 810, 858, 910, 964, 1021, 1081,
+    1146 // A#
+};
+
+static u8 octave(u8 pitch)
+{
+    return (pitch - MIN_MIDI_PITCH) / SEMITONES;
+}
+
+static u16 freqNumber(u8 pitch)
+{
+    return FREQS[((u8)(pitch - MIN_MIDI_PITCH)) % SEMITONES];
+}
+
+void midi_fm_sm_note_on(u8 chan, u8 pitch, u8 velocity)
+{
+    synth_specialModePitch(0, octave(pitch), freqNumber(pitch));
+}
+
+void midi_fm_sm_pitch_bend(u8 chan, u16 bend)
+{
+}
+
+// no-ops
+void midi_fm_sm_note_off(u8 chan, u8 pitch)
+{
+}
+
+void midi_fm_sm_channel_volume(u8 chan, u8 volume)
+{
+}
+
+void midi_fm_sm_pan(u8 chan, u8 pan)
+{
+}
+
+void midi_fm_sm_program(u8 chan, u8 program)
+{
+}
+
+void midi_fm_sm_all_notes_off(u8 chan)
+{
+}

src/midi_fm_sm.h

@@ -0,0 +1,14 @@
+#pragma once
+#include "synth.h"
+#include <stdbool.h>
+#include <types.h>
+
+void midi_fm_sm_note_on(u8 chan, u8 pitch, u8 velocity);
+void midi_fm_sm_pitch_bend(u8 chan, u16 bend);
+
+// no-ops
+void midi_fm_sm_note_off(u8 chan, u8 pitch);
+void midi_fm_sm_channel_volume(u8 chan, u8 volume);
+void midi_fm_sm_pan(u8 chan, u8 pan);
+void midi_fm_sm_program(u8 chan, u8 program);
+void midi_fm_sm_all_notes_off(u8 chan);

src/synth.c

@@ -424,3 +424,9 @@ void synth_setCh3SpecialMode(bool enable)
     global.ch3SpecialMode = enable;
     writeSpecialModeReg();
 }
+
+void synth_specialModePitch(u8 op, u8 octave, u16 freqNumber)
+{
+    YM2612_writeReg(0, 0xAC, (freqNumber >> 8) | (octave << 3));
+    YM2612_writeReg(0, 0xA8, freqNumber);
+}

src/synth.h

@@ -85,3 +85,4 @@ const FmChannel* synth_channelParameters(u8 channel);
 const Global* synth_globalParameters();
 void synth_setParameterUpdateCallback(ParameterUpdatedCallback* cb);
 void synth_setCh3SpecialMode(bool enable);
+void synth_specialModePitch(u8 op, u8 octave, u16 freqNumber);

tests/Makefile

@@ -69,6 +69,7 @@ MOCKS=midi_process \
 	synth_channelParameters \
 	synth_globalParameters \
     synth_setCh3SpecialMode \
+	synth_specialModePitch \
 	fm_writeReg \
 	midi_note_off \
 	midi_note_on \

tests/system/main.c

@@ -20,7 +20,8 @@ int main(void)
         e2e_test(test_set_device_for_midi_channel_1_to_psg),
         e2e_test(test_pong_received_after_ping_sent),
         e2e_test(test_loads_psg_envelope),
-        e2e_test(test_enables_ch3_special_mode)
+        e2e_test(test_enables_ch3_special_mode),
+        e2e_test(test_sets_separate_ch3_operator_frequencies)
         // clang-format on
     };
 

tests/system/test_e2e.c

@@ -290,3 +290,32 @@ static void test_enables_ch3_special_mode(void** state)
 
     midi_receiver_read();
 }
+
+static void test_sets_separate_ch3_operator_frequencies(void** state)
+{
+    const u8 status = 0xB0;
+    const u8 specialModeCC = 80;
+    const u8 specialModeEnable = 64;
+
+    stub_usb_receive_byte(status);
+    stub_usb_receive_byte(specialModeCC);
+    stub_usb_receive_byte(specialModeEnable);
+
+    expect_ym2612_write_reg(0, 0x27, 0x40);
+
+    midi_receiver_read();
+
+    const u8 op2MidiChannel = 10;
+    const u8 noteOnStatus = 0x90 + op2MidiChannel;
+    const u8 noteOnKey = 60;
+    const u8 noteOnVelocity = 127;
+
+    stub_usb_receive_byte(noteOnStatus);
+    stub_usb_receive_byte(noteOnKey);
+    stub_usb_receive_byte(noteOnVelocity);
+
+    expect_ym2612_write_channel(0, 0xAC, 0x22);
+    expect_ym2612_write_channel(0, 0xA8, 0x84);
+
+    midi_receiver_read();
+}

tests/unit/main.c

@@ -146,6 +146,7 @@ int main(void)
         midi_test(test_midi_switching_program_retains_pan_setting),
         midi_test(test_midi_enables_fm_special_mode),
         midi_test(test_midi_disables_fm_special_mode),
+        midi_test(test_midi_sets_pitch_of_special_mode_ch3_operator),
 
         midi_test(test_midi_sets_genmdm_stereo_mode),
         midi_test(test_midi_sysex_enables_dynamic_channel_mode),

tests/unit/test_midi_fm.c

@@ -530,3 +530,15 @@ static void test_midi_disables_fm_special_mode(UNUSED void** state)
 
     __real_midi_cc(0, expectedController, expectedValue);
 }
+
+static void test_midi_sets_pitch_of_special_mode_ch3_operator(
+    UNUSED void** state)
+{
+    int chan = 10;
+
+    expect_value(__wrap_synth_specialModePitch, op, 0);
+    expect_value(__wrap_synth_specialModePitch, octave, 4);
+    expect_value(__wrap_synth_specialModePitch, freqNumber, SYNTH_NTSC_C);
+
+    __real_midi_note_on(chan, MIDI_PITCH_C4, MAX_MIDI_VOLUME);
+}

tests/wraps.c

@@ -215,6 +215,13 @@ void __wrap_synth_setCh3SpecialMode(bool enable)
     check_expected(enable);
 }
 
+void __wrap_synth_specialModePitch(u8 op, u8 octave, u16 freqNumber)
+{
+    check_expected(op);
+    check_expected(octave);
+    check_expected(freqNumber);
+}
+
 void __wrap_comm_write(u8 data)
 {
     check_expected(data);

tests/wraps.h

@@ -62,6 +62,7 @@ void __wrap_synth_volume(u8 channel, u8 volume);
 const FmChannel* __wrap_synth_channelParameters(u8 channel);
 const Global* __wrap_synth_globalParameters();
 void __wrap_synth_setCh3SpecialMode(bool enable);
+void __wrap_synth_specialModePitch(u8 op, u8 octave, u16 freqNumber);
 
 bool __wrap_comm_read_ready(void);
 u8 __wrap_comm_read(void);