This is another board done entirely with KiCad and rolls in a few changes from the previous boards. It is completely compatible with the rev 8 boards, which were compatible with rev 7, which were compatible with… etc, etc, etc. There is no new revision of Arduino code for this board.
No new features but a few changes:
- The CR1220 battery has been replaced with a much more common CR2032 to keep the RTC (Real Time Clock) chip alive. I did extension market research (ie, I emailed all my nieces and nephews) and found they all had 2032 batteries at home, while none of them had 1220s. My family is used to getting odd emails from Uncle Bob. The local hardware store was surprised when I asked about CR1220s, so going to a more common battery makes sense.
- A different micro SD socket. The old one was push-in, pull-out, but this one is pop-in, pop-out. It also has alignment pins on the bottom making it much easier to get seated exactly in the right spot before soldering. The solder connections are at the back of the socket, not in the front like the old board. So far every surface mount solder job with the new socket has been perfect the first time, whereas the old sockets needing to be touched-up about 15% of the time.
- The old 5-pin header for an external RTC board has been removed, allowing the LEDs to be aligned in a row. With the RTC on-board there was little reason to keep the header.
- Added a clearly labeled 4-pin area for adding external I2C devices.
- For those buying the bare board, the LED colors are labeled on the silk screen. BTW, the “bare board” has the DS3231 RTC and the micro SD socket already soldered.
The rev 9k1A will eventually be changed to just rev 9, as there is no need to keep KiCad revisions uniquely identified.
