serial problems

Has anyone seen any issues with serial input when a device used a ceramic resonator rather than crystal?

I cant get 56000 input to work without scrambled characters. 9600 is better.

Trying to troubleshoot..

Is 56000 a supported rate? 57600 is the posted rate.
https://www.arduino.cc/en/Serial/Begin

Yes, I meant problems with 57600.

I have not. I use 115200 a lot.

HI,
Sounds like the resonator is not exactly on its rated frequency.
The baud rate is derived from the clock frequency.

If your comms is better at the slower rate than the high rate, although the % speed error may be the same, the tolerance at 9600baud maybe better than at the higher speed.

Tom.... :slight_smile:
(shoot me if I''m wrong, just a thought from my Microchip machine code days..ahhh memories..)

Check the specified loading capacitors.

The reason why higher baudrates are more critical is because the divisor required to approximate the baudrate clock is smaller and the division (by an odd number) is therefore less accurate, doubling the percentage error in the rate as you double the speed. If you were using a baudrate-specific crystal, this would not happen.

Just to clarify, I can send serial out at 115200 using Softserial and it's fine.

It's receiving to my PCB that gets the scrambled characters. I'm using a resonator. Wondering if I need a crystal to do this, or if I should look elsewhere to fix this.

Are you using software serial, or real serial?

Software serial is much more fiddly and prone to issues.

DrAzzy:
Are you using software serial, or real serial?

Software serial is much more fiddly and prone to issues.

Can you elaborate? I'm using softserial, but could change.