PYBv4 discussion

Discuss here the design of PYBv4.

Main things:

• Allow for 2 symmetrical skin positions (add-on modules).
• Option for external VBAT connection to power RTC domain.
• Give some ADCs proper grounding, and include AREF and AGND pins.
• Make sure USB OTG option works in a sensible way.
• Extra capacitors for SD card and near servo ports.

Form factor

It will be 33mm wide and 41mm high. It will have 16 pins running down both sides, 12 pins apart (inclusive). Thus the pin form-factor is 12x16. PYBv3 is 12x15 pins in 33x40mm, but had some spare room at the top and bottom, so only 1mm extra was needed to accommodate 1 more pin in height.

Skins will be 12x8. They will have 4 power pins (GND, VIN, 3V3, RST) and 12 GPIO pins.

Header pins

What gender should the header pins be? Female is best for skins, but need male for the servo connectors.