[minima] Re: Auto-calibration of the Si570 + some refactoring
- From: Dan Reynolds <on30ng@xxxxxxxxx>
- To: minima@xxxxxxxxxxxxx
- Date: Mon, 10 Feb 2014 11:50:38 -0600
Thomas, I would still like to see your code if possible.
73
Dan -- KB9JLO
https://sites.google.com/site/on30ng/
On Sun, Feb 9, 2014 at 8:27 PM, Thomas Sarlandie <thomas@xxxxxxxxxxxxx>wrote:
> Hi everyone!
>
> Spent some time this week-end on the Radiono software. I found out earlier
> this week that my Si570 had a very large error that grew linearly with
> frequency. We quickly found out that each module is different and you need
> to use calibration information that is saved in the module. The current
> source code has Farhan's si570 calibration hardcoded in. That will most
> likely not work for you.
>
> I have updated the Radiono source code to automatically get the
> calibration information and calculate the crystal frequency every time we
> start the program. The only information that needs to be defined in the
> source code is the default frequency programmed by the factory. In my case
> it was 56.320 but your mileage may vary.
>
> There are two ways to find this frequency:
> - Spec: Look on the marking on your Si570 (mine says CAC000141) and
> lookup some tables online to find which frequency corresponds to your
> marking (I cant find this table, if someone has it, please share!)
> - Experimental: just remove the Arduino and apply power to the control
> board. Measure the frequency at the output of the Si570.
>
> I have updated the wiki: http://www.hfsignals.org/index.php/Si570
>
> The updated source code has been submitted to Farhan in a pull-request:
> https://github.com/afarhan/radiono/pull/4
>
> Full list of changes:
>
> Split the Si570 code in a separate class.
>
> In the Si570 class:
> * Use the factory-calibrated output frequency to automatically calculate
> the internal crystal frequency and use that instead of hard coded values.
> * During initialization detect errors talking to the Si570.
> * Use multi-bytes i2c reads and writes when possible (ie: read/write
> multiple bytes without re-starting a transaction). Only works for
> read/writes in consecutive registers.
> * Use types with explicit size where that makes sense (uint8_t instead of
> char, uint64_t, etc)
> * Added some debugging on the serial console through a "debug" function
>
> In the main sketch:
> * Show a message on the LCD if the Si570 is unreachable.
> * Initialize the serial port for debugging
> * Fix some compilation warnings with string litterals being casted to char*
> * Removed unused variables
>
>
> And now, back to the soldering iron!
>
> 73,
> thomas
>
Other related posts:
