The Gizmite Development Kit is a Cortex-M4 based MCU development board, with on board ZigBee Compliant Platform wireless processor. The application MCU is a Freescale/NXP MK20DX256VLH7, 72MHz MCU featuring 256kB of flash, 64kB of RAM and 2kB of EEPROM.
This project can be supported on my Indiegogo campaign here.
- MK20DX256VLH7 72MHz Cortex-M4 MCU.
- 256kB of FLASH - 16kB reserved for bootloader.
- 64kB of SRAM.
- 2kB EEPROM.
- JN5168 ZigBee 3.0 Compliant Platform.
- 26 GPIOs.
- 6 ADCs.
- 1 UART without hardware flow control.
- 1 I2C.
- 1 SPI with single chip select.
- 1 DAC.
- 1 Analog Comparator.
- cJTAG/SWD accessible.
- 1 USB OTG port.
- 1 User controllable Button.
- 1 User controllable LED.
The 40 exposed pins also make available a 3V3 supply with up to 450mA of current available. The MCU and ZigBee processor consume no more than 50mA at peak consumption.
The JN5168 programming UART interface is exposed on the pin header, and attached to the application MCU. An extra UART from the application MCU is also available as both a host and for debugging purposes.
The first prototype PCB was produced by PCBWay you can read about my experience here.
- Power planes all connect where they need to, all segments of all ICs are powered and operating correctly.
- USB works in device mode - host mode untested.
- Debugging port works.
- Both UART channels for MCU and ZigBee processor operate as expected.
- LED and button function work as expected.
- Advanced features such as ADC, DAC and Analog Comparator are still being tested.
- ZigBee works but due to initial design flaw with chip antenna placement range is reduced.
Initial testing has revealed that antenna placement needs to be tweaked as the antenna requires being in line with the trace that feeds it rather than 90degrees to the trace like most other chip antennas. The power LED is extremely bright and wired direct into the LDO supply voltage. Future revisions will reduce the brightness and add a method to disable the LED.
Software for the board is still under active development and patches to the NuttX RTOS will be released soon to supply a basic operating system for the device. The bootloader used in testing is the community edition of uTasker, and I will be seeking licensing for this board for their bootloader as it is a reasonable solution to the problem of the Kinetis K20 series not having an on die bootrom.