Adventures in figuring out how this incredibly ubiquitous, yet incredibly mysterious integrated circuit works.
The AC690X is a family of bluetooth microcontrollers with quite amazing features for the price. They have a lot of features like FM, USB sound card mode, USB stick reader, SD card reader, BLE feature with APP (source released, for IOS and Android) some even have LCD driver and many more features [(code for the chip is written in C)]
These chips require dedicated programmer or dedicated "activator". As far as I know, you can't buy the programmer, buy you can buy the activator on aliexpress for arround $15
The activator gets the chip into some kind of DFU mode but im not sure if it after that just passes USB signal through or if it translates the usb signal somehow. I don't know since I don't have it...
this is dedicated programmer for these chips.
And this is the acivator programmer "ac69xx bluetooth chip batch activator" you can buy on aliexpress.
