Breakout Bonanza and DS1307 Realtime Clock

As if I didn’t have enough things on my “to try when I have the time” list already, I recently did a little shopping in both Adafruit and SparkFun. Both had several nifty breakout boards available that promised to speed up and streamline my breadboard projects a lot. In addition to some SMD breakouts that are still in their sealed bags, here’s what I got:

I had a lot of fun soldering the breadboard headers to these little guys. Many are for future projects, like the frequency generator which I’m planning to use for some RFID experiments, and some are just to avoid stripping apart stuff like the connector breakouts. As today’s main topic, I’m covering the DS1307 realtime clock (RTC) breakout in more detail. If you are interested in some of the other items, drop me a comment and I’ll get back to it!

DS1307 Realtime Clock

A realtime clock is simply something that keeps record of the time. Usually, these types of clocks are paired with a small coin cell battery that enables them to keep on counting even if the rest of the circuit is powered of. Such is the case with this breakout, too. Adafruit has an excellent tutorial covering the assembly of this device, all you need is some solder and an iron.

After getting it together, it took me a while to get it working. I used Bus Pirate to communicate with the chip, with the following connections:
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USB HID keyboard with V-USB

There still seems to be a lot of traffic to my V-USB tutorials, so I thought I’d write a short follow-up post on USB keyboards. I already did a USB HID mouse post earlier, so you might want to check that out to understand a bit about HID descriptors and associated V-USB settings (in short, human interface devices send a binary descriptor to PC telling what kind of “reports” they send to the host on user activities).

As a basic setup, you’ll need a working V-USB circuit with one switch and one LED attached. Here, I’m using ATtiny2313 with the LED wired to PB0 and switch to PB1. The ATtiny is using 20 MHz crystal, so if you’re following my USB tutorial series and have that circuit at hand, remember to change that frequency in usbconfig.c before trying this out. Note the cool breadboard header I have, there will be more posts about that one to follow soon!
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