dafvid / micropython-bmp280 Goto Github PK

following bosch specification (revision 1.26, page 24, section 4.3.1) the chip id is only a single byte

https://www.bosch-sensortec.com/products/environmental-sensors/pressure-sensors/bmp280/#documents

Line 54-55 in bmp280.py is :

_BMP280_OS_MATRIX = [
    [BMP280_PRES_OS_1, BMP280_TEMP_OS_1, 7],

But line 315 is:

        t_os, p_os, self.read_wait_ms = _BMP280_OS_MATRIX[oss]

t_os and p_os should be swapped. Line 316 and 317 are correct. Bits 7-5 are osrs_t and bits 4-2 are osrs_p according to the datasheet of bmp280.
The following patch should be able to fix this issue:

--- bmp280.py.orig	2022-04-26 06:07:08.000000000 +0800
+++ bmp280.py	2022-05-02 06:43:07.000000000 +0800
@@ -312,11 +312,11 @@
     def use_case(self, uc):
         assert 0 <= uc <= 5
         pm, oss, iir, sb = _BMP280_CASE_MATRIX[uc]
-        t_os, p_os, self.read_wait_ms = _BMP280_OS_MATRIX[oss]
+        p_os, t_os, self.read_wait_ms = _BMP280_OS_MATRIX[oss]
         self._write(_BMP280_REGISTER_CONFIG, (iir << 2) + (sb << 5))
         self._write(_BMP280_REGISTER_CONTROL, pm + (p_os << 2) + (t_os << 5))
 
     def oversample(self, oss):
         assert 0 <= oss <= 4
-        t_os, p_os, self.read_wait_ms = _BMP280_OS_MATRIX[oss]
+        p_os, t_os, self.read_wait_ms = _BMP280_OS_MATRIX[oss]
         self._write_bits(_BMP280_REGISTER_CONTROL, p_os + (t_os << 3), 2)

When I added all the constants from the spec the file grew quite a bit. I'm considering seperating them into a separate file you can use if you need them. This would reduce the file so that it can be more easily used on SoC with restricted storage.

Hallo,
vorab bin Anfänger!, also nehmt mir mir meine Unwissenheit nicht allzu übel.
Erfasse mit einem ESP32 und einem BMP280 die Temperatur. Bin aber nicht zufrieden mit den Meßergebnissen. Nun bich ich auf dieses Programm gestossen.
habe bisher I2C wie folgt aufgerufen:

i2c0_sda = Pin(26)
i2c0_scl = Pin(27)
i2c0 = I2C(0, sda = i2c0_sda, scl = i2c0_scl, freq = 10000)

und den Sensor:
bmp280_i2c = BMP280I2C(0x77, i2c0)

Wenn ich diesen Code aufrufe, erscheint schon bei:
bus = I2C()
eine Fehlermeldung:
TypeError: 'scl' argument required
Wie gesagt Anfänger!!!
Sicherlich muß ich noch Werte für das Argument eingeben, blos welche?

Gruß Klaus

Hi, I get the following error when using the example code in RPi Pico:

Traceback (most recent call last): File "<stdin>", line 10, in <module> File "bmp280.py", line 97, in __init__ File "bmp280.py", line 126, in _read OSError: 5

The bmp280 is visible with i2c.scan()

Also the example code should have
import bmp280

otherwise the variables are not loaded, only the class.

Looking through the code base as I'm looking for a package that does what I expect I saw this line and wondered if it should read:

        if use_case is not None:
            self.use_case(use_case)

I haven't tested either way yet, that is on the plan for tomorrow...

EDIT:
Apologies I didn't see #3 conversation. Will move to conversation on the PR.