Hi Vaibhav,

is there any reason you have to use SoftSerial? This is currently untested with EFM32. I would recommend you to use one of the hardware serial ports on the Zero Gecko kit, see the pinout diagram for more information. https://developer.mbed.org/platforms/EFM32-Zero-Gecko/

there is one leuart port and one usart port in the zero gecko starter kit. the leuart port is by default connected to the usb connected to pc.i tried using the usart port pins for the rf transmitter .but it didnt work. so i decided to use SoftSerial. I believe that the usart pins can work as uart port. but after multiple unsuccessful attempts, i decided to go with SoftSerial. Does the usart port need addition configuration before using it as uart. if yes, please let me know how to do that. A small example in this regard will be very useful.

According to Eric Oliemann, the uart and usart ports on the zero gecko starter board work only on very low baud rates as it has limited resolution on its ticker. if so, how do we resolve this? by adding an external crystal?

Hi Vaibhav, using usart as a serial port should be as simple as instantiating a Serial object with the relevant TX and RX pins. I'll see if I can create an example for you and put it up on the Zero Gecko platform page. Please bear with me as I work through my backlog, the last few days have been a little crazy.

I appreciate that you have taken some time out of you hectic schedule for considering my problem. I tried using the usart port for the rf transceiver. but it didnt work. I suspect that the signal levels are not compatible with the rf transmitter. I would like to know if there is any other rf transceiver module(not single chip) that is compatible with efm32 zero gecko starter kit. And do we have to set the clock for the uart pins in mbed compiler before initialising them?

What voltage are you driving your transceiver with? If you're trying to interface with a 5V part, a level converter (such as this one: https://www.sparkfun.com/products/12009 ) might be your best solution.

Clocking for UART is handled automatically when using the built-in Serial object.

i tried powering up the transceiver with a 5V level obtained from a simple 3.3V to 5V level shifter found on the link : http://geniusdevils.com/2013/04/3-3v-to-5v-level-shifter-circuit-with-transistor/ but wasnt successful in setting up the communication. i guess such a crude circuit would not support UART protocol due to distortion of the signal. I ll go ahead and test with a proper level converter chip and let you know the results soon. Can you suggest someone from silabs bangalore office who can help me with this issue if i approach him/her in person?

also used a level shifter chip, but no communication was established

hey,

i would like to know how to set up my zero gecko starter kit board to operate at 1MHz frequency.

Hi Vaibhav,

Currently, mbed on Silicon Labs platforms is not ideally suited for custom clock configurations. You'd have to set the clock speed define (in the board header file) to 1 MHz, and set the HFXO clock tree divider manually.

hello,

I was working on the efm32 starter kit board when suddenly the board stopped functioning . the lcd display stopped working and a yellow led started blinking above the red led for reset. the device is no longer detected on the system and simplicity studio. please let me know what is wrong.