Exactly what is the maximum baud rate for 1mHz?
How about 8?
F_CPU/8 So, 125000 and 1Mbps, respectively.
An additional problem is that as you get close to the maximum bitrate, the values you can achieve become very "quantized": F_CPU/8, F_CPU/9, F_CPU/10, etc. So at 1MHz you have 125000bps, 111111bps, 100000bps... You don't get close to a "standard" baud rate till 9600bps.
CantSayIHave:
Exactly what is the maximum baud rate for 1mHz?
How about 8?
The relevant Atmel Datasheet contains tables showing the exact answer.
...R
CantSayIHave:
How about 8?
You should be able to do better than 8 bits per second. Let me see ... yes, I just tested it and got 115200 baud at 8 MHz.
CantSayIHave:
Exactly what is the maximum baud rate for 1mHz?
How about 8?
When using Arduinos interrupt driven "Serial" or when using low-level register programming and polling?
With Arduinos "Serial" I can get max. 500000 @16MHz, so I'd suppose that you could possibly get 500000/16 @1MHz which would be 31250 Baud.
Not a standard baudrate, so you cannot use it with the serial monitor.
But most terminal software programs on a PC should be able to use non-standard baudrates.
So at 1 MHz it should be 1/8 of that (14400).
Exactly what is the maximum baud rate for 1mHz?
One clock tick every 16 minutes 40 seconds?
Good point. 1 mHz is actually very slow.
Yeah, English speakers often are unaware that "m" (milli, 10^-3) and 'M' (Mega, 10^6) are quite different scaling factors 
With a 1MHz clock the maximum baudrate is 500kBaud (clock/2).
But isn't a standard baudrate also required for programming the device, so that a 1MHz clock could cause headaches?
With Arduinos "Serial" I can get max. 500000 @16MHz, so I'd suppose that you could possibly get 500000/16 @1MHz which would be 31250 Baud.
Not a standard baudrate, so you cannot use it with the serial monitor.
isn't 31250 the standard midi baud rate?
DrDiettrich:
Yeah, English speakers often are unaware that "m" (milli, 10^-3) and 'M' (Mega, 10^6) are quite different scaling factors
English Speakers?
apparently, but i learned something this morning... thank you for that
KeithRB:
English Speakers?
My Bowers and Wilkins speakers are English, and are utterly ignorant of the prefixes 'm' and 'M'
DrDiettrich:
Yeah, English speakers often are unaware that "m" (milli, 10^-3) and 'M' (Mega, 10^6) are quite different scaling factors
That has nothing to do with their language - just ignorance of SI nomenclature.
If you have no particular interest in science it is a rather arcane piece of knowledge.
...R
I think the point was that folks familiar with the metric system would have more familiarity with prefixes, while those of us raised on Imperial units would be hopelessly confused.
But I doubt that many folks that grew up with the metric system have much call for the M prefix anyway, and might easily get confused, too.
useless pedants. Has anyone actually seen m vs M prefixes misused in a situation where the correct interpretation wasn't obvious from context?
(all those pre-70s era capacitors labeled in "mf" and "MFD" and "mmf" and so on probably don't help.)
westfw:
useless pedants.
Perhaps. But the OP did seem to be asking if the maximum baud rate was 8.
CantSayIHave:
Exactly what is the maximum baud rate for 1mHz?
How about 8?
Although re-reading the question I see now that s/he probably means "how about 8 MHz"? I didn't get that on the first reading. I thought s/he asked: "what is the maximum baud rate for 1 MHz? Is it 8 baud?"
I occasionally get confused when talking about bytes, kb and Mb and Gb. These units appear to use the metric prefixes but don't follow the convention.
edit: at least you don't have to worry about mb or ub.
Thank you very much for the clarification on "m" vs. "M". I suppose a 1mHz clock would not be very useful.
As to the 8 thing, I was just jumping from 1MHz to 8MHz and assuming you would make the connection, I'm sorry for not clarifying. 1MHz and 8MHz are just generally the most common ATtiny speeds, considering most people don't also order crystals.
Thanks for the answers!
jboyton:
I occasionally get confused when talking about bytes, kb and Mb and Gb. These units appear to use the metric prefixes but don't follow the convention.
There is a standard for that...
Atmel claims the ATmega328P has 32 Kbytes of Flash but it really has 32 kibibytes (abbreviated 32 KiB).