The core oscillator of this circuit is the same as in my TRIVCO module, an OTA-based relaxation oscillator, so this module can be used as a VCO as well.

The triangle output is strictly above 0V while the inverted triangle output is centered to 0V. The triangle output is strictly positive so I can reliably pull it down to 0V with the RESET input.

No more shape control, only way to get a sawtooth signal is to connect its square-wave output into the RESET input.

The module that you see in the picture above is using circuit boards that were fabricated by PCBWay. They have excellent build quality and I can recommend using their service to build your own projects! I used the "Black" option for the soldermask and the surface has very deep and glossy black finish, which looks amazing, they also have an option for a "Matte Black" finish which I will try next time. Thank you PCBWay for sponsoring this module. Their website is very intuitive to use, just upload the gerber files as a .zip-file, tick the options such as base material, board width, my favorite feature: separate colors for the soldermask and silkscreen, surface finish etc. With multiple options for payment and fast delivery fast times I was able to put the entire project together in less than one month.