CapTIvate Touch Keypad BoosterPack
|
The CapTIvate Touch Keypad BoosterPack is a welcome addition to the the CapTIvate Development Kit with a ready-to-use numeric pad.
It features a numeric keypad with additional pads for enter and cancel. The MSP430FR2522 comes flashed with firmware to send the proximity and the digits pressed through UART and I²C. |
|
Hardware
|
The board includes 12 pads for the ten digits, enter and cancel, plus 14 red LEDs, one per pad and two for awake and detect.
The MSP430FR2522 manages the capacitive touch and sends the data through serial and I²C ports, and activates an interrupt to pin 12 or 27. The LP3943 drives the LEDs and is connected to the MSP430FR2522 through a secondary I²C bus. |
|
Software
|
For an unknown reason, the firmware didn't work as expected. A logic analyser showed a flat trace for the clock and data lines of the I²C bus.
Right, the logic trace with Channel 0 black for IRQ-A, Channel 5 green for I²C SDA and Channel 6 blue for I²C SCL. |
|
|
However, I connected the board to a USB port through the programmer included in the CapTIvate Development Kit and used the CapTIvate™ Design Center GUI for MSP430™ Capacitive Sensing MCUs.
The CapTIvate GUI displayed all the pads touched, and the proximity sensor as well. |
|
|
Luckily, the source code is provided as a CCS project. To solve the issue, I imported the project into CCS, built it and uploaded it using the programmer from the CapTIvate Development Kit.
Eventually, the clock and data lines of the I²C bus worked as expected. The BoosterPack acts as an I²C slave device with 6 registers, as described at the I²C Slave Register Map Specification section. However, I wasn't able to use the last status registers. Right, the logic trace with Channel 0 black for IRQ-A, Channel 5 green for I²C SDA and Channel 6 blue for I²C SCL. |
|
|
After a period of inactivity, the BoosterPack enters low power mode. The LEDs are then turned off.
When proximity is detected, the BoosterPack wakes up and turns the LEDs on. Pressing one pad turns the LED even brighter, although the finger hides it. The LEDs are managed by the BoosterPack itself, and are not exposed to the LaunchPad I²C bus. |
|
Pins Map
Conclusion
|
I was unpleasantly surprised by the issue with the flashed firmware. I had to build and flash the firmware from CCS to get the I²C bus activated. Although easy, the process requires an external programmer, taken from the CapTIvate Development Kit.
Once flashed with the correct firmware, the BoosterPack worked as expected, with proximity detection and clear reading of the pads touched. Developing a library for Energia was quick to complete. |
Pros
|
Cons
|
Wrap-Up
|
