SerialPort configuration for MIDI

[pourkascheff]

Hi all, Conventional MIDI serial protocol - as its developers say - runs at 31250 baud rate, 8 data bits, 1 stop bit, 1 start bit and none parity (not sure for this one). The underlined item does not exist in SerialPort control properties in VB.NET what should I do?

[pourkascheff]

Here's the MIDI configurations: https://ccrma.stanford.edu/~gary/con...ata%22%20byte.

And SerialPort class/properties as Microsoft documentations say: https://docs.microsoft.com/en-us/dot...t-plat-ext-6.0

[pourkascheff]

As a faultfinding action, behavior to pressing middle 'C' key was monitored and results are shown in table below:

Status Byte (1)	Pitch Byte (2)	Velosity Byte (3)
0X20	0XF8	don't care

Which expected results are:

Status Byte (1)	Pitch Byte (2)	Velosity Byte (3)
0X90	0X3C	don't care

Serial Port settings: 31250 sps baud rate, 8 bits data, 1 stop bit, parity (none and mark same results)

In a similar way for Key-off event there is:

Status Byte (1)	Pitch Byte (2)	Velosity Byte (3)
0X00	0XF8	0X00 0XFF

Which correct response should be (A hundred percent sure that it should be 3 bytes max):

Status Byte (1)	Pitch Byte (2)	Velosity Byte (3)
0X80	0X3C	0X40

My inference is there's a '1' bit shifted to left. Consider 0x90 (1001 0000) to 0x20 (0010 0000) and similarly 0x80 (1000 0000) to 0x00 (0000 0000).
Should I keep looking to rectify the Serial Port 1 start bit additional setting?
Or correct every receiving byte by shifting 1 bit to right? (>>1 with 1 for status bytes, >>1 with 0 for value byte(s))?

[pourkascheff]

Update: Well, nothing new were achieved and no answers yet... but, there's a promising thing about uart protocol which can appliable on every kind of microcontrollers. The 'start bit' thing had been built-in on this protocol - thanks to its developers - And as it can be monitored by PC, it should be a way to configure SerialPort control with 1 start bit to spy a MIDI simplex communication.

Here's the uart data frame:
Attachment 184794

[dbasnett]

I believe one start bit is default / standard. I'd collect a lot of bytes from the device and look for patterns. Are you certain you are capturing all messages?

Look at this MIDI tutorial.https://learn.sparkfun.com/tutorials...l/all#messages

[pourkascheff]

Are you certain you are capturing all messages?

Yes sir, Note On messages (for middle 'C') are 3 bytes all the time and they are repeatable. Here's the sniffed packets (For note on middle 'C'): Cursor point to the end are Note Off for middle 'C' messages which should be 3 bytes and last FF is a wrong reading obviously.


If you mean are buffered data digitally okay? I might say 'not sure' because my oscilloscope is an audio frequency range one, so I'm not able to see what's going on but the cp2102 uart to usb converter proofed to be OK in recent projects. That's the reason I'm suspected to Visual Studio low-level configuration or such.

[dbasnett]

Yes sir, Note On messages (for middle 'C') are 3 bytes all the time and they are repeatable. Here's the sniffed packets (For note on middle 'C'): Cursor point to the end are Note Off for middle 'C' messages which should be 3 bytes and last FF is a wrong reading obviously.
Attachment 184801

If you mean are buffered data digitally okay? I might say 'not sure' because my oscilloscope is an audio frequency range one, so I'm not able to see what's going on but the cp2102 uart to usb converter proofed to be OK in recent projects. That's the reason I'm suspected to Visual Studio low-level configuration or such.

Can't see any of your attachments...

[pourkascheff]

Can't see any of your attachments...

Corrected sir.

[dbasnett]

In the link I posted there is a finite state machine with a heading of Message Parsing.

Did you follow that? Did you read the paragraphs that follow it?

[pourkascheff]

In the link I posted there is a finite state machine with a heading of Message Parsing.
Did you follow that? Did you read the paragraphs that follow it?

Um, not quite sir. I mean I forgot moore's diagram and how to extract its functionality. But what I'm one hundred percent sure is that UART protocol includes 1 start bit in itself which can easily achievable on C based microcontrollers IDEs but how do to such thing in VB (The mothership of most of them)?

[dbasnett]

Um, not quite sir. I mean I forgot moore's diagram and how to extract its functionality. But what I'm one hundred percent sure is that UART protocol includes 1 start bit in itself which can easily achievable on C based microcontrollers IDEs but how do to such thing in VB (The mothership of most of them)?

https://www.vbforums.com/showthread....=1#post5566895

[pourkascheff]

(2023 Update) Well, I know it is not even entered to VisualStudio VB.NET yet... I was going to do things with received bytes but since readings are invalid/wrong I should rectify it first.

Is my code-generating machine produces them wrongly? Could it be faulty? Nothing else came up to my mind... I'm using Alesis Q49 it is USB MIDI-controller but also covers a DIN5 conventional port. I used DIN5 with external power same identical wrong reading.

I am considering to create an account on Gearspace.com (formerly called Gearslutz)