Required UART clock frequency to achieve 1M baudrate on 343026

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SaEa_4705941
Level 3
Level 3
25 replies posted 10 replies posted 10 questions asked

Hi,

I am using puart of EVAL-343026(In EZ-serial mode) connected to an external host MCU, So far I can communicate with the EVAL in lower baudrates such as 115200 while with a UART clock frequency of  8MHz. I am getting garbage values when increasing the baudrate close to 1M.

Please help me on how to choose the UART clock frequency in order to achieve a 1M baudrate between the host and EVAL.

Regards,

Se

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8 Replies
Owen_Zhang123
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5 questions asked 500 solutions authored 250 sign-ins

Are you using the EZ-Serial FW? Did you set the UART baudrate with command STU?

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Yes, I am using STU to set the baudrate. I am Atsamd51 as the host micro controller and would like to know what UART clock frequency needs to be used from the MCU side to achieve reliable communication @1M baudrate

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It depends on the UART configuration on your host MCU. You need to check the oversample value of your MCU.

Theoretically, the baudrate error of the UART on your host MCU should be no more than 5%.

I am using hardware flow control, and success in communicating at a baud rate of 921600. I am using Atmel studio and when I am using the breakpoints to analyse the responses(from the CYBT module) on the Rx buffer of the MCU, sometimes I am getting corrupted values in the middle.  The test code executes the 'get name' command every 100ms.

What are the timing characteristics of CYBT-343026 in API mode? I couldn't find relevant information in this manual

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Could you check the UART communication with a logic analyzer to see if the data is wrong?

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Due to working from home, I don't have access to lab until next week. In the mean time, could you provide any information with regards to the timing characteristics during EZ-serial text mode? 

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The EZ-Serial uses standard UART profile. It should work if the UART baudrate is match.

Besides, the device may enter sleep mode. Could you try to pull the LP_MODE pin (I2C_SDA/P12) to VDD and see if the problem still happens?

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I have LP_MODE,CYPP pins pulled to VDD already.

Still got corrupted bytes now and then. I think I need to verify the baudrate from the MCU to see whether it's matching.

Currently using the internal clock which is less accurate compared to and external crystal.

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