EFM32 Zero Gecko MCUs

EFM32 MCUs were designed to be used in low power applications. Implementations based on ARM Cortex-M3 and M4 were available for quite some time now. The recent release of Zero Gecko devices based on ARM Cortex-M0+ makes it nice candidate for porting mbed SDK.

First attempt is made to port mbed to EFM32ZG110F32 MCU.

What is special about EFM32ZG110F32 ?

• Cost: Devices with 32 KB flash and 4 KB RAM are available for around 1 U.S.D.
• 12bit 1 Msamples/s ADC
• 1 Analog comparator
• 1 Current DAC
• 4 channel DMA
• 2× 16-bit Timer/Counter(3 Compare/Capture/PWM channels), 1× 16-bit Pulse Counter
• Inbuilt 24-bit Real-Time Counter which consumes just 0.9 μA @ 3 V in Deep Sleep mode.
• On-chip temperature sensor, which can be used for sensing ambient temperature (with some clever use).
• Configurable GPIO drive strength up-to 20mA (which is good for LED driving!) .
• I2C, SPI, UART
• Hardware AES
• Peripheral Reflex System ( A bus used for autonomous communication of peripherals without CPU intervention)
• Upto 24 Mhz clock.

Harware Board

Designed a board for EFM32ZG110 target board.I just got the orderd MCUs. Waiting for the PCB.

Challenges ahead

• Initially I worked on a port with M3/M4 EFM32 devices. I had used two 16-bit timers to implement uTicker. But, ZG110 only has two 16-bit timers. At most, I can use one 16-bit timer. The other 16-bit timer should be used for PWMout
• Possibility of using SysTickTimer for uTicker need to be explored. Since SysTickTimer is only used for RTOS, non-RTOS mbed application could make use of SysTickTimer.