homeduino on a 8Mhz Pro Mini fails

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I tried using a Pro Mini 3.3v@8Mhz for the homeduino plugin, but every command came back as ERR unknown_command.

Switching to an Uno 3.3v@16Mhz worked fine with no other changes. Unfortunately only have one pi at the moment, and alrady loving pimatic more than the tellstick.net stuff I used before so slightly reluctant to keep digging at the moment. But figured I’d make a post if anyone else tries the same and fails as I found no hits when searching.

@Bjørn-Eikeland
Are you sure about your Hardware?
I think you did change the settings in Arduino and Homeduino sources to meet the right Hardware when compiling and uploading to the µC?
I’v also bought some cheap ProMinis from China giving me problems (in other DIY proj.). Against the description they are not with 8MHz! Try to use a simple program to check if the oszillation meets what you think it should.

I’ve only used a simple blink + echo program to “test” the boards. But the uart baud rate, and firmware download work fine so they have to be running at 8Mhz.

I’ll try to do a little digging besides the rpi over the weekend.

I am not sure that we have encapsulate all the timing stuff from the clock rate. Easiest way to solve this is to use a 16MHz type.

Interesting thing was it worked fine on my Uno R3 running with clock_prescale_set (clock_div_2); so if there is a timing issue and not a quality of cheap china clones issue then it might be related to F_CPU=16000000L vs F_CPU=8000000L and timing derived from that.

I have got the same trouble with Pro Mini 3.3v@8Mhz

This issue isn’t directly related to homeduino. It is common: Arduino @ 8MHz and serial on 115200 are inaccurate.

More information:
Trouble with 115200 baud on 3.3V/8MHz Arduino, like Serial Gateway. Solution: Change baudrate.
Pro mini 3.3v 8 Mhz 115200 baud issue

Solutions:
One: Use 57600 baud rate on Arduino @ 8MHz. Note: Homeduino sketch and, of course, pimatic plugin settings should be modified.
Two: Use 115200 baud rate on Arduino @ 16MHz

@leader21
Should be worth to add a info at HowTo, plugin and homeduino page ?

yes, will do so!
thx for the information

Edit : done