How to calc max debug rate?

[circuitpro]

I'd like to know how to determine the maximum DEBUG baudrate using a PIC18F2420 running on an INTERNAL 8 MHz oscillator? Can someone help me out here?

[ScaleRobotics]

You can run debug at 38400 using 8 mhz, but I don't know the calculation.

Walter

[circuitpro]

I was hoping for 57600, but knew it would be close. I never know until I try, but can't do that until tomorrow. I just dont have the space on this board for an external xtal/osc.

[rmteo]

Turn on the PLL to get a 32MHz clock?

[circuitpro]

I've been reading that the clock frequency is not as stable and may need to be tuned over time. In this application, it's going to be pretty inaccessable and I need to be able to trust that the serial port will work reliably over time, so I've pretty much decided against the PLL.

[mackrackit]

I've been reading that the clock frequency is not as stable and may need to be tuned over time.
You are using the internal already, so PLLing will not change that.

[circuitpro]

I see now that you are right! I remembered that, but thought that it was PLL related NOT the entire internal osc block. The memory is the second thing to go. Guess I'll do some temperature tests this week.

[Dave]

scalerobotics
You can run debug at 38400 using 8 mhz, but I don't know the calculation.

Walter

What calculation? It's just:

OSC 8
DEFINE DEBUG_BAUD 38400

Dave Purola,
N8NTA

[ScaleRobotics]

What calculation? It's just:

OSC 8
DEFINE DEBUG_BAUD 38400


Yes it is. But I was talking about "How to calc max debug rate?" I do not have that calculation. From what I have read Debug is smaller and faster than Serial, but I don't see any speed tables for debug anywhere.

[circuitpro]

Just for the record, it would be nice to have a table, formula, or rule-of-thumb to follow so you can know if debug will work at a particular baud rate without having to build the design first.