Conversion line capable of recording MIDI and audio

Abstract

The utility model discloses a conversion line capable of recording MIDI and audio frequency, comprising an MCU module, a USB connector connected with the MCU module, an MIDI isolation circuit used for communicating with an external MIDI device connected with the MIDI isolation circuit, and an audio frequency conversion circuit connected with the external MIDI isolation circuit. The monitoring output circuit is used for outputting audio information; the LINE IN circuit module is provided with a LINE IN input circuit used for inputting audio signals, a LINE IN signal circuit used for detecting whether the audio signals are input or not, and a LINE IN distortion circuit used for giving an alarm when the input audio signals are too large; and the microphone processing circuit is used for accessing an audio signal input by a microphone. Compared with the prior art, the utility model not only supports the mutual communication between the MIDI musical instrument and the computer, but also can record the musical instrument audio and the microphone audio and monitor the input audio at the same time, thereby providing convenience for users.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic musical instrument field, especially a conversion line that can record MIDI and audio. BACKGROUND

[0002] MIDI recording is used for connecting the musical instrument with MIDI five needle mouth to the computer, and communicating with the computer software. Audio recording is used for recording the musical instrument audio and microphone audio, and transmitting the audio to the computer through USB. In the existing MIDI conversion line, generally only support converting MIDI five needle mouth into USB port, and is used for the recording of MIDI, but does not support the recording and monitoring of analog audio. If the user needs to record audio and MIDI, two recording devices need to be used, which is very inconvenient.

[0003] Therefore, how to design a conversion line that can record MIDI and audio, so that the user can record MIDI, and can record audio and monitor audio is an urgent problem in the industry. UTILITY MODEL CONTENT

[0004] In view of the problem in the prior art that the MIDI conversion line generally only supports converting MIDI five needle mouth into USB port, and is used for the recording of MIDI, but does not support the recording and monitoring of analog audio, the utility model provides a conversion line that can record MIDI and audio.

[0005] The technical scheme of the utility model provides a conversion line that can record MIDI and audio, comprising an MCU module, and a USB connector connected with the MCU module, further comprising:

[0006] A MIDI isolation circuit is connected with a MIDI IN interface and a MIDI OUT interface, and is used for communicating with the connected external MIDI device;

[0007] A monitoring output circuit is connected with an earphone audio output port, and is used for outputting audio information;

[0008] A LINE IN circuit module has a LINE IN input circuit for inputting audio signals, a LINE IN signal circuit for detecting whether the audio signals are inputted, and a LINE IN distortion circuit for warning when the audio signals are inputted too large;

[0009] A microphone processing circuit is connected with a microphone input port, and is used for inputting the audio signals inputted by the microphone.

[0010] Furthermore, the MIDI isolation circuit includes: connector CON6, resistor R6, resistor R14, resistor R15, resistor R16, resistor R1, resistor R22, resistor R23, diode D1, transistor Q1, transistor Q2, capacitor C18, and optocoupler U3.

[0011] The base of transistor Q1 is connected in series with resistor R16 and then connected to the MTX pin of the MCU module. The collector of transistor Q1 is connected in series with resistor R6 and then connected to a 5V DC power supply. The emitter of transistor Q1 is grounded.

[0012] The base of transistor Q2 is connected between the collector of transistor Q1 and the resistor R6. The collector of transistor Q2 is connected in series with the resistor R15 and then connected to the first pin of connector CON6. The emitter of transistor Q2 is grounded.

[0013] The second and fifth pins of connector CON6 are grounded, the third pin of connector CON6 is connected to a 5V DC power supply after being connected in series with resistor R15, the fourth pin of connector CON6 is connected to the second terminal of the control terminal of optocoupler U3, the sixth pin of connector CON6 is connected to the first terminal of the control terminal of optocoupler U3 after being connected in series with resistor R22, and the diode D1 is connected between the first and second terminals of the control terminal of optocoupler U3.

[0014] The first terminal of the controlled end of the optocoupler U3 is grounded, the second terminal of the controlled end of the optocoupler U3 is connected in series with the resistor R23 and then connected to the MRX pin of the MCU module, the third terminal of the controlled end of the optocoupler U3 is connected to a 5V DC power supply, one end of the resistor R17 is connected between the resistor R23 and the second terminal of the controlled end of the optocoupler U3, and the other end of the resistor R17 is connected to a 5V DC power supply.

[0015] Furthermore, the monitoring output circuit includes: potentiometer RP2, capacitor C5, capacitor C6, and audio interface PJ-342;

[0016] The potentiometer RP2 has a third adjustable resistor and a fourth adjustable resistor. The first end of the third adjustable resistor is connected to the DAC-L pin of the MCU module, the second end of the third adjustable resistor is grounded, and the third end of the third adjustable resistor is connected to the capacitor C5. The first end of the fourth adjustable resistor is connected to the DAC-R pin of the MCU module, the second end of the fourth adjustable resistor is grounded, and the third end of the fourth adjustable resistor is connected to the capacitor C6. The other ends of both capacitors C5 and C6 are connected to the audio interface PJ-342.

[0017] Furthermore, the LINE IN input circuit includes: potentiometer RP1, resistor R1, resistor R2, resistor R3, resistor R4, capacitor C2, capacitor C4, bidirectional diode D4, bidirectional diode D5, and audio interface PJ-342.

[0018] The potentiometer RP1 has a first adjustable resistor and a second adjustable resistor. The first terminals of both the first and second adjustable resistors are connected to the audio interface PJ-342. The second terminals of both the first and second adjustable resistors are grounded. The third terminal of the first adjustable resistor is connected to the LINEIN-R pin of the MCU module after being connected in series with the resistor R1 and the capacitor C2. The third terminal of the second adjustable resistor is connected to the LINEIN-L pin of the MCU module after being connected in series with the resistor R4 and the capacitor C4.

[0019] One end of the resistor R2 and the bidirectional diode D4 is connected between the capacitor C2 and the resistor R1, and the other end of the resistor R2 and the bidirectional diode D4 is grounded;

[0020] One end of the resistor R3 and the bidirectional diode D5 is connected between the capacitor C4 and the resistor R4, and the other end of the resistor R3 and the bidirectional diode D5 is grounded.

[0021] Furthermore, the LINE IN distortion circuit includes: resistors R8, R9, R10, R11, R12, and R13; capacitor C15; diodes D8 and D9; indicator light LED1; and comparator U2A.

[0022] The positive terminal of diode D8 is connected to the LINEIN-R pin of the MCU module, the positive terminal of diode D9 is connected to the LINEIN-L pin of the MCU module, the negative terminals of diode D8 and diode D9 are both connected to one end of resistor R13, and the other end of resistor R13 is connected to the non-inverting input of comparator U2A.

[0023] One end of resistor R8 is connected to a 3.3V power supply, and the other end of resistor R8 is connected in series with resistor R9 and then grounded. One end of resistor R11 is connected between resistor R8 and resistor R9, and the other end of resistor R11 is connected to the inverting input of comparator U2A.

[0024] The output of the comparator U2A is connected in series with the resistor R12 and the indicator LED1 and then grounded. One end of the capacitor C15 is connected to the 5V power supply, and the other end of the capacitor C15 is grounded. One end of the resistor R10 is connected between the output of the comparator U2A and the resistor R12, and the other end of the resistor R10 is connected between the capacitor C15 and the 5V power supply.

[0025] Furthermore, the LINE IN signal circuit includes: resistors R21, R24, R26, R30, R32, R33, diode D8, diode D9, indicator LED5, and comparator U2B;

[0026] The anode of diode D8 is connected to the LINEIN-R pin of the MCU module, the anode of diode D9 is connected to the LINEIN-L pin of the MCU module, the cathodes of diode D8 and D9 are both connected to one end of resistor R30, and the other end of resistor R30 is connected to the non-inverting input of comparator U2B.

[0027] The inverting input of comparator U2B is connected to a 3.3V power supply after being connected in series with resistors R26 and R24. One end of resistor R32 is connected between resistors R24 and R26, and the other end of resistor R32 is grounded. The output of comparator U2B is connected to a ground after being connected in series with resistor R21 and indicator LED5. One end of resistor R33 is connected between the output of comparator U2B and resistor R21, and the other end of resistor R33 is connected to a 5V power supply.

[0028] Furthermore, the microphone processing circuit includes: resistors R27, R31, R34, R35, R36, R37, R38, and R39; capacitors C19, C20, C22, C23, C25, C26, C27, C28, C29, and C30; a bidirectional diode D2; an amplifier U4; and an audio interface PJ-342.

[0029] The first terminal of amplifier U4 is connected to the MIC pin of the MCU module via series connection of capacitor C30 and resistor R39. The second terminal of amplifier U4 is grounded. The fourth terminal of amplifier U4 is connected to the audio interface PJ-342 via series connection of resistor R37 and capacitor C27. One end of resistor R35 is connected to a 3.3V power supply, and the other end of resistor R35 is connected to ground via series connection of resistor R36. The third terminal of amplifier U4 is connected between resistors R35 and R36. One end of resistor R34 is connected to a 3.3V power supply, and the other end of resistor R34 is connected to one end of capacitors C22 and C23 respectively. The other ends of capacitors C22 and C23 are both grounded. The fifth terminal of amplifier U4 is connected between capacitor C22 and resistor R34 and between capacitor C23 and resistor R34 respectively.

[0030] Resistor R38 is connected between the first and fourth terminals of amplifier U4. Capacitor C29 is connected in parallel across resistor R38. One end of capacitor C28 is connected between resistor R37 and capacitor C27, and the other end of capacitor C28 is grounded. One end of bidirectional diode D2 is connected between capacitor C27 and audio interface PJ-342, and the other end of bidirectional diode D2 is grounded. Capacitors C19 and C20 are both connected in parallel across resistor R36. One end of resistor R27 is connected to a 3.3V power supply, and the other end of resistor R27 is connected in series with resistor R31 and then connected to audio interface PJ-342. One end of capacitor C25 is connected between resistor R27 and resistor R31, and the other end of capacitor C25 is grounded. Capacitor C26 is connected in parallel across capacitor C25.

[0031] Furthermore, it also includes a mode button for turning the audio output on or off and for adjusting the audio effect. One end of the mode button is grounded, and the other end of the mode button is connected in series with the resistor R25 and then connected to the KEY pin of the MCU module.

[0032] Furthermore, it also includes at least one indicator module for displaying communication status, the indicator module including indicator LED2, indicator LED3, indicator LED4, resistor R18, resistor R19, and resistor R20;

[0033] One end of the indicator LED2 is connected to a 3.3V power supply, and the other end of the indicator LED2 is connected in series with the resistor R18 and then connected to the LED3 pin of the MCU module;

[0034] One end of the indicator LED3 is connected to a 3.3V power supply, and the other end of the indicator LED3 is connected in series with the resistor R19 and then connected to the LED2 pin of the MCU module;

[0035] One end of the indicator LED4 is connected to a 3.3V power supply, and the other end of the indicator LED4 is connected in series with the resistor R20 and then connected to the LED1 pin of the MCU module.

[0036] Furthermore, the MCU module uses the UA3125T chip.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] This invention supports communication between MIDI instruments and computers, records instrument and microphone audio, monitors input audio, and outputs computer audio, providing convenience for users. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the modules of the present utility model.

[0041] Figure 2 This is a connection diagram of the MCU module of this utility model;

[0042] Figure 3 This is a connection diagram of the LINE IN circuit module of this utility model;

[0043] Figure 4 This is a connection diagram of the microphone processing circuit of this utility model;

[0044] Figure 5 This is a schematic diagram of the connection of the monitoring output circuit of this utility model. Detailed Implementation

[0045] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0046] Therefore, a feature pointed out in this specification is used to describe one feature of one embodiment of the present invention, and does not imply that every embodiment of the present invention must have the described feature. Furthermore, it should be noted that this specification describes many features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0047] The principle and structure of this utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0048] Existing MIDI converter cables generally only support converting a MIDI 5-pin connector to a USB connector for MIDI recording, but do not support analog audio recording and monitoring. Users who need to record both audio and MIDI need to use two different recording devices, which is very inconvenient.

[0049] To address the aforementioned problems, this utility model proposes a converter cable capable of recording MIDI and audio, including an MCU module, a USB connector for connecting to the MCU module, and further comprising:

[0050] The MIDI isolation circuit has a MIDI IN interface and a MIDI OUT interface for communicating with the connected external MIDI device;

[0051] The monitoring output circuit is connected to a headphone audio output port for outputting audio information;

[0052] The LINE IN circuit module has a LINE IN input circuit for inputting audio signals, a LINE IN signal circuit for detecting whether an audio signal is input, and a LINE IN distortion circuit for warning when the audio signal input is too large.

[0053] The microphone processing circuit is connected to a microphone input port for receiving audio signals from the microphone.

[0054] Please see Figure 1 This utility model has a MIDI IN interface and a MIDI OUT interface, a headphone audio output port, a musical instrument audio input port, a microphone input port, and a USB connector;

[0055] Its functions include connecting to a computer via a USB connector for communicating audio and MIDI information and providing power;

[0056] Connect external MIDI devices via MIDI IN and MIDI OUT interfaces and communicate with them;

[0057] Connect to an external analog audio output via the instrument audio input port;

[0058] Connect an external microphone for audio input via the microphone input port;

[0059] Connect headphones via the headphone output jack to output audio from LINE IN, microphone, and computer.

[0060] This utility model can realize the above-mentioned communication functions through the above-mentioned interface and the MIDI isolation circuit, monitoring output circuit, LINE IN circuit module and microphone processing circuit connected to the above-mentioned interface respectively, so as to achieve the purpose of supporting mutual communication between MIDI instruments and computers, recording instrument audio and microphone audio, and monitoring input audio as described above.

[0061] Please see Figure 2 The MIDI isolation circuit in this utility model includes: connector CON6, resistor R6, resistor R14, resistor R15, resistor R16, resistor R1, resistor R22, resistor R23, diode D1, transistor Q1, transistor Q2, capacitor C18, and optocoupler U3.

[0062] The base of transistor Q1 is connected in series with resistor R16 and then connected to the MTX pin of the MCU module. The collector of transistor Q1 is connected in series with resistor R6 and then connected to a 5V DC power supply. The emitter of transistor Q1 is grounded.

[0063] The base of transistor Q2 is connected between the collector of transistor Q1 and resistor R6. The collector of transistor Q2 is connected in series with resistor R15 and then connected to the first pin of connector CON6. The emitter of transistor Q2 is grounded.

[0064] The second and fifth pins of connector CON6 are grounded. The third pin of connector CON6 is connected to a 5V DC power supply after being connected in series with resistor R15. The fourth pin of connector CON6 is connected to the second terminal of the control terminal of optocoupler U3. The sixth pin of connector CON6 is connected to the first terminal of the control terminal of optocoupler U3 after being connected in series with resistor R22. Diode D1 is connected between the first and second terminals of the control terminal of optocoupler U3.

[0065] The first terminal of the controlled end of optocoupler U3 is grounded. The second terminal of the controlled end of optocoupler U3 is connected to the MRX pin of the MCU module after being connected in series with resistor R23. The third terminal of the controlled end of optocoupler U3 is connected to a 5V DC power supply. One end of resistor R17 is connected between resistor R23 and the second terminal of the controlled end of optocoupler U3, and the other end of resistor R17 is connected to a 5V DC power supply.

[0066] Please see Figure 5The monitoring output circuit of this utility model includes: potentiometer RP2, capacitor C5, capacitor C6, and audio interface PJ-342;

[0067] Potentiometer RP2 has a third adjustable resistor and a fourth adjustable resistor. The first end of the third adjustable resistor is connected to the DAC-L pin of the MCU module, the second end of the third adjustable resistor is grounded, and the third end of the third adjustable resistor is connected to capacitor C5. The first end of the fourth adjustable resistor is connected to the DAC-R pin of the MCU module, the second end of the fourth adjustable resistor is grounded, and the third end of the fourth adjustable resistor is connected to capacitor C6. The other ends of capacitors C5 and C6 are both connected to audio interface PJ-342.

[0068] Please see Figure 3 The LINE IN input circuit of this utility model includes: potentiometer RP1, resistor R1, resistor R2, resistor R3, resistor R4, capacitor C2, capacitor C4, bidirectional diode D4, bidirectional diode D5, and audio interface PJ-342.

[0069] Potentiometer RP1 has a first adjustable resistor and a second adjustable resistor. The first terminals of both the first and second adjustable resistors are connected to the audio interface PJ-342. The second terminals of both the first and second adjustable resistors are grounded. The third terminal of the first adjustable resistor is connected to the LINEIN-R pin of the MCU module after being connected in series with resistor R1 and capacitor C2. The third terminal of the second adjustable resistor is connected to the LINEIN-L pin of the MCU module after being connected in series with resistor R4 and capacitor C4.

[0070] One end of resistor R2 and bidirectional diode D4 is connected between capacitor C2 and resistor R1, and the other end of resistor R2 and bidirectional diode D4 is grounded.

[0071] One end of resistor R3 and bidirectional diode D5 is connected between capacitor C4 and resistor R4, and the other end of resistor R3 and bidirectional diode D5 is grounded.

[0072] The LINE IN distortion circuit includes: resistors R8, R9, R10, R11, R12, and R13; capacitor C15; diodes D8 and D9; indicator LED1; and comparator U2A.

[0073] The positive terminal of diode D8 is connected to the LINEIN-R pin of the MCU module, the positive terminal of diode D9 is connected to the LINEIN-L pin of the MCU module, and the negative terminals of diodes D8 and D9 are both connected to one end of resistor R13. The other end of resistor R13 is connected to the non-inverting input of comparator U2A.

[0074] One end of resistor R8 is connected to a 3.3V power supply, and the other end of resistor R8 is connected to ground in series with resistor R9. One end of resistor R11 is connected between resistor R8 and resistor R9, and the other end of resistor R11 is connected to the inverting input of comparator U2A.

[0075] The output of comparator U2A is connected in series with resistor R12 and indicator LED1, and then grounded. One end of capacitor C15 is connected to the 5V power supply, and the other end of capacitor C15 is grounded. One end of resistor R10 is connected between the output of comparator U2A and resistor R12, and the other end of resistor R10 is connected between capacitor C15 and the 5V power supply.

[0076] The LINE IN signal circuit includes: resistors R21, R24, R26, R30, R32, and R33; diodes D8 and D9; indicator light LED5; and comparator U2B.

[0077] The positive terminal of diode D8 is connected to the LINEIN-R pin of the MCU module, the positive terminal of diode D9 is connected to the LINEIN-L pin of the MCU module, and the negative terminals of diodes D8 and D9 are both connected to one end of resistor R30. The other end of resistor R30 is connected to the non-inverting input of comparator U2B.

[0078] The inverting input of comparator U2B is connected to a 3.3V power supply after being connected in series with resistors R26 and R24. One end of resistor R32 is connected between resistors R24 and R26, and the other end of resistor R32 is grounded. The output of comparator U2B is connected to a ground after being connected in series with resistor R21 and indicator light LED5. One end of resistor R33 is connected between the output of comparator U2B and resistor R21, and the other end of resistor R33 is connected to a 5V power supply.

[0079] Please see Figure 4 The microphone processing circuit of this utility model includes: resistors R27, R31, R34, R35, R36, R37, R38, and R39; capacitors C19, C20, C22, C23, C25, C26, C27, C28, C29, and C30; a bidirectional diode D2; an amplifier U4; and an audio interface PJ-342.

[0080] The first terminal of amplifier U4 is connected to the MIC pin of the MCU module via series capacitor C30 and resistor R39. The second terminal of amplifier U4 is grounded. The fourth terminal of amplifier U4 is connected to the audio interface PJ-342 via series resistor R37 and capacitor C27. One end of resistor R35 is connected to a 3.3V power supply, and the other end of resistor R35 is connected to ground via series resistor R36. The third terminal of amplifier U4 is connected between resistors R35 and R36. One end of resistor R34 is connected to a 3.3V power supply, and the other end of resistor R34 is connected to one end of capacitors C22 and C23 respectively. The other ends of capacitors C22 and C23 are both grounded. The fifth terminal of amplifier U4 is connected between capacitor C22 and resistor R34 and between capacitor C23 and resistor R34 respectively.

[0081] Resistor R38 is connected between the first and fourth terminals of amplifier U4. Capacitor C29 is connected in parallel across resistor R38. One end of capacitor C28 is connected between resistor R37 and capacitor C27, and the other end of capacitor C28 is grounded. One end of bidirectional diode D2 is connected between capacitor C27 and audio interface PJ-342, and the other end of bidirectional diode D2 is grounded. Capacitors C19 and C20 are both connected in parallel across resistor R36. One end of resistor R27 is connected to a 3.3V power supply, and the other end of resistor R27 is connected in series with resistor R31 and then connected to audio interface PJ-342. One end of capacitor C25 is connected between resistor R27 and resistor R31, and the other end of capacitor C25 is grounded. Capacitor C26 is connected in parallel across capacitor C25.

[0082] Please see Figure 2 The present invention also includes a mode button for turning the audio output on and off and for adjusting the audio effect. One end of the mode button is grounded, and the other end of the mode button is connected in series with a resistor R25 and then connected to the KEY pin of the MCU module.

[0083] Please see Figure 2 The present invention also includes at least one indicator module for displaying communication status, the indicator module including indicator LED2, indicator LED3, indicator LED4, resistor R18, resistor R19, and resistor R20;

[0084] One end of indicator LED2 is connected to a 3.3V power supply, and the other end of indicator LED2 is connected to the LED3 pin of the MCU module after being connected in series with resistor R18.

[0085] One end of indicator LED3 is connected to a 3.3V power supply, and the other end of indicator LED3 is connected to the LED2 pin of the MCU module after being connected in series with resistor R19.

[0086] One end of indicator LED4 is connected to a 3.3V power supply, and the other end of indicator LED4 is connected to the LED1 pin of the MCU module after being connected in series with resistor R20.

[0087] Furthermore, the MCU module described above in this utility model uses the UA3125T chip.

[0088] Based on the above connections, the overall working logic of this utility model is as follows:

[0089] like Figure 2 and Figure 3 As shown, this invention powers the MCU module via a USB connector, and the MCU module can generate 3.3V for use by other module circuits. External MIDI devices are connected via connector CON6 and communicate with the MCU module through a MIDI isolation circuit. Indicator lights include MIDI and USB status lights, LED1 in the LINE_IN distortion circuit, and LED5 in the LINE_IN signal circuit.

[0090] The instrument audio is input through the audio port J1 of the PJ-342 audio interface. The input amplitude can be adjusted by potentiometer RP1. After passing through the LINE_IN input circuit, LINE_IN distortion circuit, and LINE_IN signal circuit, the audio is transmitted to the microcontroller module. The LINE_IN signal circuit is used to detect the instrument audio input and displays it via indicator LED5. The LINE_IN distortion circuit is used to prevent distortion caused by excessive external audio input, as indicated by indicator LED1.

[0091] like Figure 2 , Figure 4 ,and Figure 5 As shown, audio port J3 of the audio interface PJ-342 is used to connect a microphone, which is then input to the MCU module via the microphone input circuit. The MCU module's monitoring audio output ports DAC_LO and DAC_RO are output to audio port J2 of the audio interface PJ-342 via the monitoring output circuit, and the output audio amplitude can be adjusted via potentiometer RP2.

[0092] Based on the above-mentioned design, this utility model has the following beneficial effects:

[0093] This invention supports communication between MIDI instruments and computers, records instrument and microphone audio, monitors input audio, and outputs computer audio, providing convenience for users.

[0094] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A converter cable for recording MIDI and audio, comprising an MCU module and a USB connector connected to the MCU module, characterized in that, Also includes: The MIDI isolation circuit has a MIDI IN interface and a MIDI OUT interface for communicating with the connected external MIDI device; The monitoring output circuit is connected to a headphone audio output port for outputting audio information; The LINE IN circuit module has a LINE IN input circuit for inputting audio signals, a LINE IN signal circuit for detecting whether an audio signal is input, and a LINE IN distortion circuit for warning when the audio signal input is too large. The microphone processing circuit is connected to a microphone input port for receiving audio signals from the microphone.

2. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The MIDI isolation circuit includes: connector CON6, resistor R6, resistor R14, resistor R15, resistor R16, resistor R1, resistor R22, resistor R23, diode D1, transistor Q1, transistor Q2, capacitor C18, and optocoupler U3. The base of transistor Q1 is connected in series with resistor R16 and then connected to the MTX pin of the MCU module. The collector of transistor Q1 is connected in series with resistor R6 and then connected to a 5V DC power supply. The emitter of transistor Q1 is grounded. The base of transistor Q2 is connected between the collector of transistor Q1 and the resistor R6. The collector of transistor Q2 is connected in series with the resistor R15 and then connected to the first pin of connector CON6. The emitter of transistor Q2 is grounded. The second and fifth pins of connector CON6 are grounded, the third pin of connector CON6 is connected to a 5V DC power supply after being connected in series with resistor R15, the fourth pin of connector CON6 is connected to the second terminal of the control terminal of optocoupler U3, the sixth pin of connector CON6 is connected to the first terminal of the control terminal of optocoupler U3 after being connected in series with resistor R22, and the diode D1 is connected between the first and second terminals of the control terminal of optocoupler U3. The first terminal of the controlled end of the optocoupler U3 is grounded, the second terminal of the controlled end of the optocoupler U3 is connected in series with the resistor R23 and then connected to the MRX pin of the MCU module, the third terminal of the controlled end of the optocoupler U3 is connected to a 5V DC power supply, one end of the resistor R17 is connected between the resistor R23 and the second terminal of the controlled end of the optocoupler U3, and the other end of the resistor R17 is connected to a 5V DC power supply.

3. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The monitoring output circuit includes: potentiometer RP2, capacitor C5, capacitor C6, and audio interface PJ-342; The potentiometer RP2 has a third adjustable resistor and a fourth adjustable resistor. The first end of the third adjustable resistor is connected to the DAC-L pin of the MCU module, the second end of the third adjustable resistor is grounded, and the third end of the third adjustable resistor is connected to the capacitor C5. The first end of the fourth adjustable resistor is connected to the DAC-R pin of the MCU module, the second end of the fourth adjustable resistor is grounded, and the third end of the fourth adjustable resistor is connected to the capacitor C6. The other ends of both capacitors C5 and C6 are connected to the audio interface PJ-342.

4. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The LINE IN input circuit includes: potentiometer RP1, resistor R1, resistor R2, resistor R3, resistor R4, capacitor C2, capacitor C4, bidirectional diode D4, bidirectional diode D5, and audio interface PJ-342. The potentiometer RP1 has a first adjustable resistor and a second adjustable resistor. The first terminals of both the first and second adjustable resistors are connected to the audio interface PJ-342. The second terminals of both the first and second adjustable resistors are grounded. The third terminal of the first adjustable resistor is connected to the LINEIN-R pin of the MCU module after being connected in series with the resistor R1 and the capacitor C2. The third terminal of the second adjustable resistor is connected to the LINEIN-L pin of the MCU module after being connected in series with the resistor R4 and the capacitor C4. One end of the resistor R2 and the bidirectional diode D4 is connected between the capacitor C2 and the resistor R1, and the other end of the resistor R2 and the bidirectional diode D4 is grounded; One end of the resistor R3 and the bidirectional diode D5 is connected between the capacitor C4 and the resistor R4, and the other end of the resistor R3 and the bidirectional diode D5 is grounded.

5. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The LINE IN distortion circuit includes: resistors R8, R9, R10, R11, R12, and R13; capacitor C15; diodes D8 and D9; indicator light LED1; and comparator U2A. The positive terminal of diode D8 is connected to the LINEIN-R pin of the MCU module, the positive terminal of diode D9 is connected to the LINEIN-L pin of the MCU module, the negative terminals of diode D8 and diode D9 are both connected to one end of resistor R13, and the other end of resistor R13 is connected to the non-inverting input of comparator U2A. One end of resistor R8 is connected to a 3.3V power supply, and the other end of resistor R8 is connected in series with resistor R9 and then grounded. One end of resistor R11 is connected between resistor R8 and resistor R9, and the other end of resistor R11 is connected to the inverting input of comparator U2A. The output of the comparator U2A is connected in series with the resistor R12 and the indicator LED1 and then grounded. One end of the capacitor C15 is connected to the 5V power supply, and the other end of the capacitor C15 is grounded. One end of the resistor R10 is connected between the output of the comparator U2A and the resistor R12, and the other end of the resistor R10 is connected between the capacitor C15 and the 5V power supply.

6. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The LINE IN signal circuit includes: resistors R21, R24, R26, R30, R32, and R33; diode D8; diode D9; indicator light LED5; and comparator U2B. The anode of diode D8 is connected to the LINEIN-R pin of the MCU module, the anode of diode D9 is connected to the LINEIN-L pin of the MCU module, the cathodes of diode D8 and D9 are both connected to one end of resistor R30, and the other end of resistor R30 is connected to the non-inverting input of comparator U2B. The inverting input of comparator U2B is connected to a 3.3V power supply after being connected in series with resistors R26 and R24. One end of resistor R32 is connected between resistors R24 and R26, and the other end of resistor R32 is grounded. The output of comparator U2B is connected to a ground after being connected in series with resistor R21 and indicator LED5. One end of resistor R33 is connected between the output of comparator U2B and resistor R21, and the other end of resistor R33 is connected to a 5V power supply.

7. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The microphone processing circuit includes: resistors R27, R31, R34, R35, R36, R37, R38, and R39; capacitors C19, C20, C22, C23, C25, C26, C27, C28, C29, and C30; a bidirectional diode D2; an amplifier U4; and an audio interface PJ-342. The first terminal of amplifier U4 is connected to the MIC pin of the MCU module via series connection of capacitor C30 and resistor R39. The second terminal of amplifier U4 is grounded. The fourth terminal of amplifier U4 is connected to the audio interface PJ-342 via series connection of resistor R37 and capacitor C27. One end of resistor R35 is connected to a 3.3V power supply, and the other end of resistor R35 is connected to ground via series connection of resistor R36. The third terminal of amplifier U4 is connected between resistors R35 and R36. One end of resistor R34 is connected to a 3.3V power supply, and the other end of resistor R34 is connected to one end of capacitors C22 and C23 respectively. The other ends of capacitors C22 and C23 are both grounded. The fifth terminal of amplifier U4 is connected between capacitor C22 and resistor R34 and between capacitor C23 and resistor R34 respectively. Resistor R38 is connected between the first and fourth terminals of amplifier U4. Capacitor C29 is connected in parallel across resistor R38. One end of capacitor C28 is connected between resistor R37 and capacitor C27, and the other end of capacitor C28 is grounded. One end of bidirectional diode D2 is connected between capacitor C27 and audio interface PJ-342, and the other end of bidirectional diode D2 is grounded. Capacitors C19 and C20 are both connected in parallel across resistor R36. One end of resistor R27 is connected to a 3.3V power supply, and the other end of resistor R27 is connected in series with resistor R31 and then connected to audio interface PJ-342. One end of capacitor C25 is connected between resistor R27 and resistor R31, and the other end of capacitor C25 is grounded. Capacitor C26 is connected in parallel across capacitor C25.

8. The converter cable for recording MIDI and audio according to claim 1, characterized in that, It also includes a mode button for turning the audio output on and off and for adjusting the audio effect. One end of the mode button is grounded, and the other end of the mode button is connected in series with a resistor R25 and then connected to the KEY pin of the MCU module.

9. The converter cable for recording MIDI and audio according to claim 1, characterized in that, It also includes at least one indicator module for displaying communication status, the indicator module including indicator LED2, indicator LED3, indicator LED4, resistor R18, resistor R19, and resistor R20; One end of the indicator LED2 is connected to a 3.3V power supply, and the other end of the indicator LED2 is connected in series with the resistor R18 and then connected to the LED3 pin of the MCU module; One end of the indicator LED3 is connected to a 3.3V power supply, and the other end of the indicator LED3 is connected in series with the resistor R19 and then connected to the LED2 pin of the MCU module; One end of the indicator LED4 is connected to a 3.3V power supply, and the other end of the indicator LED4 is connected in series with the resistor R20 and then connected to the LED1 pin of the MCU module.

10. The converter cable for recording MIDI and audio according to claim 1, characterized in that, The MCU module uses the UA3125T chip.

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