it's my own design based around stm32h7 micro. It's a multichannel audio mixer recorder.
The app requests the bytes that are ascii values that represent text ( recorded audio file names ) each file name is comma separated.
The device repeatedly streams out audio levels ( 8 bytes in the packer , 1 byte per audio channel level ) unless the app requests the bytes for file names.
There are 11 bytes in total in a packet.
2 x 0x08 byte packet begin marker
1 x 0x00 or 0x01 byte to determine what the packet is for.
so a 3 byte header I suppose you could call it.
The bluetooth receive part in the app is being triggered by a clock set to 30 in appinventor.. 30ms? I'm not sure..
when looking at the file browser screen there is no need for audio levels but no audio packets are sent while the device sends the audio file name ascii byte code. those packets are the same length , 11 bytes.
I was hoping to load the file names into a list picker so the user can select a file and play it on the device. I would only need to send back the list ID number for the device to know which file to play.
I don't as of yet have an end of filenames byte sent in the last header. I'll do that if I can get the text converted and separated out from the commas
I think i'm doing something wrong with the chr function , asci code -> text ? maybe the chr function needs to return to a string ? or is list ok ?
The audio level data is working well and staying in sync before and after going into the audio file menu.
so the packets seam to align correctly.