Keep getting uart error at UART0_IRQHandler at app_art_fifo using app_trace

[Chaiwat Sungkhobol]

Hi,

I am wondering what to do to fix the error I have been getting while trying to debug my project. I am using app_trace for logging. I would often get an error on the UART0_IRQHandler. I is happen more often now for some reason. It comes and go. My speed is 460800 No flow control TX buffer size 512 I believe the app_trace is using FiFO buffer.

Thank you

[Susheel Nuguru]

If you do not have flow control then overflow errors are bound to happen at the speed you mentioned. The driver is not reading fast enough, are you using having BLE radio activity along with this?

[Chaiwat Sungkhobol]

I am using Softdevice with this.
The IRQ priority is low. If I set it to high it works but the Softdevice dies.
If i use a lower speed it happens more often. I will try to find a flow control uart converter to test it out.

[Susheel Nuguru]

the combination of softdevice and given uart speed on 16 MHZ processor is not feasable, you need flow control for this. if you use APP_HIGH priority on interrupt handler with this UART speed then softdevice will starve and will assert.

[Chaiwat Sungkhobol]

What do you think the setting should be? what Baud and buffer size should i set it at for non flow control?

[Susheel Nuguru]

It does not matter how low baudrate you have, if the peer uart sends data when the driver on nordic chip is blocked by softdevice, and if the internal buffer is full then we cannot avoid loosing packets. This can happen at very low baud rates too without flow control devzone.nordicsemi.com/.../