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Asked: 2026-05-23T08:43:14+00:00

I am using EVK1105 development board with AVR Studio 5 as development IDE for

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I am using EVK1105 development board with AVR Studio 5 as development IDE for my AVR project.
I am using FreeRTOS in it. I have 3 USART ports on this board. One external module is connected to my AVR32 board via USART-RS232 mode. It sends me continuous serial data to my board on USART0 with 19230 baudrate, 7-databits, odd parity, stopbit-1 and normal-channel mode. I created a new task for this purpose. After each 9 data bytes it sends ‘\n’ and ‘\r’. So in my task I keep on collecting the 9 databytes in a string buffer and then transmit it on USART1. I am using polling method to collect data from USAR0 which is receiving port. But I am facing problem in receiving data. I don’t know if its timing issue or something or the scheduler switches the task while collects the data. But I don’t get the required data.

Following are things I have already checked as troubleshooting
1. Connected my external module to my PC hyper-terminal which gives me perfect result.
2. Implemented the same thing of using receiving from USART0 and whatever received is transmitted to USART1 as without FreeRTOS. Its works fine.

Please suggest some idea what may be wrong. I am using a queue to communicate between Tx and Rx task to pass the string buffer from USART0 to USART1. Is it problem in handling queue? How can I troubleshoot the queue?

I am using a delay of 50ms in my infinite task loop in Rx Task. Can it create a problem? If I don’t use any delay the OS crashes. Please suggest some good practices to create a new task in FreeRTOS so that I will not get any timing issue.

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1 Answer

  1. Editorial Team

    For such a use case, I would not use a polling method with 50ms delay to retrieve data from UART peripheral. You can easily lose received data depending on the system load and UART reception buffer size.

    At least use an interrupt on UART data reception that copies every received byte into a local buffer that will be read by your TX thread.

    You can have an even better solution using a DMA channel to receive your data frame and be notified when 9 bytes have been received. I don’t know if your AVR device has a DMA peripheral or not.

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