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MiniDexed/src/serialmididevice.cpp

98 lines
2.3 KiB

//
// serialmididevice.cpp
//
// MiniDexed - Dexed FM synthesizer for bare metal Raspberry Pi
// Copyright (C) 2022 The MiniDexed Team
//
// Original author of this class:
// R. Stange <rsta2@o2online.de>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
#include "serialmididevice.h"
#include <assert.h>
CSerialMIDIDevice::CSerialMIDIDevice (CMiniDexed *pSynthesizer, CInterruptSystem *pInterrupt,
CConfig *pConfig)
: CMIDIDevice (pSynthesizer, pConfig),
m_pConfig (pConfig),
m_Serial (pInterrupt, TRUE),
m_nSerialState (0)
{
}
CSerialMIDIDevice::~CSerialMIDIDevice (void)
{
m_nSerialState = 255;
}
boolean CSerialMIDIDevice::Initialize (void)
{
assert (m_pConfig);
return m_Serial.Initialize (m_pConfig->GetMIDIBaudRate ());
}
void CSerialMIDIDevice::Process (void)
{
// Read serial MIDI data
u8 Buffer[100];
int nResult = m_Serial.Read (Buffer, sizeof Buffer);
if (nResult <= 0)
{
return;
}
// Process MIDI messages
// See: https://www.midi.org/specifications/item/table-1-summary-of-midi-message
for (int i = 0; i < nResult; i++)
{
u8 uchData = Buffer[i];
switch (m_nSerialState)
{
case 0:
MIDIRestart:
if ( (uchData & 0x80) == 0x80 // status byte, all channels
&& (uchData & 0xF0) != 0xF0) // ignore system messages
{
m_SerialMessage[m_nSerialState++] = uchData;
}
break;
case 1:
case 2:
if (uchData & 0x80) // got status when parameter expected
{
m_nSerialState = 0;
goto MIDIRestart;
}
m_SerialMessage[m_nSerialState++] = uchData;
if ( (m_SerialMessage[0] & 0xE0) == 0xC0
|| m_nSerialState == 3) // message is complete
{
MIDIMessageHandler (m_SerialMessage, m_nSerialState);
m_nSerialState = 0;
}
break;
default:
assert (0);
break;
}
}
}