So a primary project of mine right now is to reinvent my alarm clock. I have an old POS I probably bought for $10 from a department store over 10 years ago that still works..... for the most part, but its digits are too small for my squinty eyes to see across the bedroom at 3AM when my son likes to wake us up for no good reason.
Obviously the first line of business here, then, in reinventing an alarm clock is the display. I like red displays at night, and I like larger digits, so Adafruit's 1.2" red LED display was perfect- http://www.adafruit.com/products/1264
They sell one with an I2C backpack too (HT16K33-based). But something just doesn't jive right with me there; I want mine overengineered to the point of exhaustion. So I designed my own backpack with suitable P-channel and N-channel MOSFET transistors controlled by an MSP430F5172. Used the F5172 for two reasons: Native 5V on some pins (great for direct control of the P-channel's when powering the LEDs with 5V for maximum brightness & compatibility with different LED colors), and Timer_D should give me an absolutely hideously inappropriate amount of brightness control if I PWM the P-channel FETs using a Timer_D output.
In any case, board fabricated, my first test revision of the Spy-Bi-Tag for eZ-FET all assembled and my new Tag-Connect TC2030-MCP programming cable in hand (bought last month), I've given it a test. Just lighting up one thing at a time to make sure all the cathode & anode lines work.
Looks good so far:
Don't mind the FuelTank boosterpack, I noticed that my eZ-FET-to-Spy-Bi-Tag adapter didn't offer any options for connecting the 5V or 3.3V rails to the rest of the LaunchPad for sending 5V/3.3V to the project, so I popped on the FT BPak to cover that for now. In any case, that Spy-Bi-Tag eZ-FET adapter will need at least 1 more revision before I feel it's good enough to publish. I must say though, the eZ-FET programs the F5172 nice & fast!
Another thing I noticed is I put the Tag-Connect footprint way too close to the 2x5 power/data IDC connector; I've bent one of the corner pins on the IDC pinout many times trying to get my fingernail in there to pinch the connector legs, although I got it down to a science now so I'm not hurting it anymore. That said, I'm pretty impressed with the Tag-Connect and the legged version doesn't seem all that hard to install & remove; a bit of effort but nothing horrible IMO, no tools required to be sure (just pinch & pull at the same time to remove).
This LED Display Backpack offers a 2x5 connector suitable for IDC which has two GND's, 5V, 3.3V, and a number of GPIOs from P1.0-P1.5 for the full USCI experience; choose whatever protocol you want to use to talk to this one! I'm planning on using UART in my final alarm clock project. The main brain of the alarm clock will likely be an F5529 LaunchPad, and the mainboard will include enough circuitry to charge two tablets at the same time, or a tablet and a phone, or two phones, or 1 phone or tablet or whatever. Got samples of TI's TPS2511 for that part of the project.
Probably going to ignore the RTC's on the MSP430's and use the DS3231 for keeping time, although I might change my mind.