What is it?

A breakout board for a CSR8635 development module with pin labels.

Note: There are three main variants of these boards with different pin layouts:

1. Commonly listed as BTM-835B - this board has pins on all sides and requires an external antenna. It is generally a board with blue solder mask.
2. Commonly listed as BTM835 - this board generally has it's chip angled at 45° and has an equal amount of pins on both of the long sides. This one generally has a blue solder mask.
3. Commonly listed as BC8635 - Usually has green solder mask and the two long sides have 14 and 15 pins respectively.

AliExpress is my go-to for procuring them. Here are links to a couple:

http://s.aliexpress.com/VfaueAnM

http://s.aliexpress.com/ruANJr6B

Why did you make it?

I am working on building a Bluetooth audio headset but didn't realize how small the pins on these modules are. For prototyping my device, I wanted to be able to use this board on a breadboard and have a visual reference to the pinouts.

What makes it special?

These Bluetooth audio boards are super cheap and I'd love to see more people able to prototype with them. Look out for my headset project coming in a couple months.