peterhinch / micropython-samples

Line 113 in 0d27d95

def getcal(self, minutes=5, cal=0, verbose=True):

The calibration routine for 1.x boards seems to be broken. I made a minor change to ds3231_pb.py to force using get_cal (1.x boards):

d_series = os.uname().machine.split(' ')[0][:4] == 'PYBD'
if d_series:
    machine.Pin.board.EN_3V3.value(1)
d_series = False # Force 1.x get_cal

And running the following script using a PYBD_SF2 results in out of range calibration value:

paste mode; Ctrl-C to cancel, Ctrl-D to finish
=== from ds3231_pb import DS3231
=== from machine import I2C
=== 
=== ds3231 = DS3231(I2C(2))
=== print("DS3231 RTC Time:", ds3231.get_time(set_rtc=True))
=== 
=== import time
=== print(time.localtime())
=== 
=== ds3231.calibrate()
=== 
DS3231 RTC Time: (2021, 9, 12, 7, 42, 48, 0, 0)
(2021, 9, 12, 7, 42, 48, 0, 255)
Pyboard 1.x. Waiting 5 minutes for calibration factor.
Error -6332.2ppm -12050.1mins/year. Cal factor 6637
Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
  File "ds3231_pb.py", line 182, in calibrate
ValueError: calibration value out of range

I think I have one of the very first boards could dig it up and test with if needed.

I don't understand why you changed it. This has been tested against Pyboard D SF2W and SF6W, as described in the doc. Why do you want to use Pyboard 1.1 code against a Pyboard D?

Why do you want to use Pyboard 1.1 code against a Pyboard D?

I don't, I just wanted to test the 1.x function and all I had was a D board (SF2W).

I can assure you that the calibration routine does work when run against a Pyboard 1.x.

I can assure you that the calibration routine does work when run against a Pyboard 1.x.

Evidently it's not:

MicroPython v1.17-20-g0a5107372-dirty on 2021-09-13; PYBLITEv1.0 with STM32F411RE
Type "help()" for more information.
>>> 
paste mode; Ctrl-C to cancel, Ctrl-D to finish
=== from ds3231_pb import DS3231
=== from machine import I2C
=== 
=== ds3231 = DS3231(I2C(3))
=== print("DS3231 RTC Time:", ds3231.get_time(set_rtc=True))
=== 
=== import time
=== print(time.localtime())
=== 
=== ds3231.calibrate()
=== 
DS3231 RTC Time: (2021, 9, 13, 5, 36, 39, 1, 0)
(2021, 9, 13, 5, 36, 39, 1, 256)
Pyboard 1.x. Waiting 5 minutes for calibration factor.
Error -52822.7ppm -100521.5mins/year. Cal factor 55369
Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
  File "ds3231_pb.py", line 183, in calibrate
ValueError: calibration value out of range

I can help with testing if you are interested in fixing it, otherwise just ignore my comment.

The Pyboard Lite does not have a crystal controlled clock so cannot be calibrated. It works when run against a Pyboard 1.0 or 1.1, which do have crystals and can run to timepiece levels of precision when calibrated.

The Pyboard Lite does not have a crystal controlled clock so cannot be calibrated

Oh I see the issue now, there's a footprint for the 32Khz crystal maybe I'll try it later, thanks for your time and sorry for the noise 😐

ds3231 calibration for Pyboard 1.x seems broken.