Cross-Compile and import

[jwissing]

I have come to the same memory error just by using the BME280 module.
viewtopic.php?f=14&t=1315
I have tried to get around this by precompiling the module using the cross-compiler as suggested by pythoncoder.
http://forum.micropython.org/viewtopic. ... 876#p10542
This is what i have done:
cd into mpy-cross
running make in this directory
running the resulting ./mpy-cross binary to compile the BME280.py module to BME280.mpy
I have gotten it downloaded to flash as BME280.mpy
When i now get this error when i try to import it:

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PYB: soft reboot
could not open file 'main.py' for reading
MicroPython v1.8-21-g9e47c14-dirty on 2016-05-08; ESP module with ESP8266
Type "help()" for more information.
>>> ls()
['boot.py', 'port_config.py', 'BME280.mpy', 'util.py', 'wlanconnect.py', 'file', 'BMP1801.py', 'test.py', 'testget.py']
>>> import BME280
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: no module named 'BME280'

Any hints what i'm doing wrong?

Update:
This approach does not seem to work by now.
I increased heap size and the import worked.
The board with BME280 sensor is deployed in the basement and is reporting the measurements via mqtt to my openhab server.
The measurement are collected into a mongodb collection for later analysis.

[jwissing]

I got it to work with increased heap size and small modifications to BME280:

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>>> import BME280
>>> b=BME280.BME280(i2c=i2c)
>>> dir(b)
['read_pressure', 'read_humidity', '_load_calibration', '__init__', '__qualname__', 'read_raw_humidity', 'read_temperature', 'humidity', 'read_raw_pressure', 'temperature', '__module__', 'pressure', 'read_raw_temp', 'dig_P6', 'dig_P7', 'dig_P8', 'dig_P9', 'dig_H2', 'dig_H3', 'dig_H1', 'dig_H6', 'dig_H4', 'dig_H5', '_mode', '_device', 'dig_T2', 'dig_T3', 'dig_T1', 't_fine', 'dig_P1', 'dig_P2', 'dig_P3', 'dig_P4', 'dig_P5']
>>> b.temperature
'29.19C'
>>> b.humidity
'28.53%'
>>> b.pressure
'998.03hPa'
>>>

main.c:

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STATIC char heap[40 * 1024];

[Roberthh]

@pfalcon : Is there a way to enable cross -compiled byte code?
Best regards

[slzatz]

I have a font file of the structure:

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cols = 5
rows = 8
bytes = [
    0x00, 0x00, 0x00, 0x00, 0x00,
    ...
    0x20, 0x54, 0x54, 0x78, 0x40,
    0x38, 0x44, 0x44, 0x28, 0x7F,
    0x3C, 0x26, 0x23, 0x26, 0x3C]
 

It appears to successfully compile to a .mpy file but when I transfer it to flash and import I get module not found. I have created a very small version of the file and cross-compiled it with the same result. Is there something about that file structure that won't compile to an .mpy that can be successfully imported?

[Roberthh]

Cross-compiled files seem not to be imported yet. That's why I asked whether there is a build option to achieve that, lile it is possible on WiPy.

[slzatz]

Since @jwissing seems to have made it work on the esp, it seems like it's possible today. Would be great to understand how it's done and whether the .mpy has to be compiled with the firmware or can be copied to the esp flash file system.

[Roberthh]

As far as I understand the posts of @jwissing, he increased the heap and then the .py version of his script worked.
The pre-compiled versions will still not be accepted as python scripts.

[slzatz]

@Roberthh - thanks - I had misinterpreted what had worked. Am in the same position, I can get things to work with the font.py module I have but would very much like to turn it into frozen bytecode -- will stay tuned to see if/when that is possible via the esp port.