Search found 88 matches

by chuckbook
Tue Jul 03, 2018 11:42 am
Forum: Other Boards
Topic: [pyb.ADCAll()] strange results
Replies: 3
Views: 451

Re: [pyb.ADCAll()] strange results

Self calibration for F4 & F7 means evaluation of Vref by means of factory calibration parameters for temp sensor and internal band-gap reference. It has nothing to do with ADC calibration.
by chuckbook
Mon Jul 02, 2018 4:46 pm
Forum: Other Boards
Topic: [pyb.ADCAll()] strange results
Replies: 3
Views: 451

Re: [pyb.ADCAll()] strange results

Be aware of the fact that so far only a limited number of MCUs (F405, F411, F7xx) are supported when it comes to internal voltage readout and self calibration.
by chuckbook
Mon Jun 18, 2018 8:00 am
Forum: General Discussion and Questions
Topic: uctypes and spi
Replies: 5
Views: 461

Re: uctypes and spi

CCM RAM is not accessible via DMA.
DocID018909 Rev 10, 2.1, pp 59
by chuckbook
Tue May 22, 2018 3:28 pm
Forum: General Discussion and Questions
Topic: RTC (Clock) is too slow on PyBoard Lite v1.0 with accelrometer
Replies: 6
Views: 638

Re: RTC (Clock) is too slow on PyBoard Lite v1.0 with accelrometer

It should be mentioned that PYBLITE doesn't use a crystal for the RTC but an RC oscillator. However, it is pretty easy to solder in a TH crystal.
by chuckbook
Tue Apr 10, 2018 9:22 am
Forum: General Discussion and Questions
Topic: CPython/MicroPython returns different result of time.localtime()
Replies: 2
Views: 440

Re: CPython/MicroPython returns different result of time.localtime()

MPY epoch is 2000-01-01 instead of unix epoch, which is 1970-01-01.

Code: Select all

>>> time.localtime(1523338307-time.UNIX_TIME)
(2018, 4, 10, 6, 31, 47, 1, 100)
Note:
I'm not sure if time.UNIX_TIME is defined in the master repository. It is just a constant

Code: Select all

>>> time.UNIX_TIME
946681200
by chuckbook
Fri Apr 06, 2018 11:00 am
Forum: MicroPython pyboard
Topic: Controlling Slew Rate of GPIO
Replies: 13
Views: 1803

Re: Controlling Slew Rate of GPIO

If I remember correctly the (usually unwanted) parasitic capacity from overlapping gate and drain is indeed called Miller capacity.
by chuckbook
Thu Apr 05, 2018 8:04 am
Forum: MicroPython pyboard
Topic: Controlling Slew Rate of GPIO
Replies: 13
Views: 1803

Re: Controlling Slew Rate of GPIO

BTW, it is interesting that Rds seems to be constant. So I guess it is just a variation of the gate area or using multiple gates.
by chuckbook
Wed Apr 04, 2018 11:04 am
Forum: MicroPython pyboard
Topic: Controlling Slew Rate of GPIO
Replies: 13
Views: 1803

Re: Controlling Slew Rate of GPIO

Just a quick test run. Scope probe connected with two wet shoelaces to Y5 and GND of a PYBLITE to simulate lousy wiring.
The 150Ohm load was just measured with a step whereas other tests used a pulse.
GPIO_SLOW_150OHM
GPIO_SLOW_OPEN
GPIO_FAST_OPEN
by chuckbook
Tue Apr 03, 2018 10:30 am
Forum: MicroPython pyboard
Topic: is my pyboard broken or am i missing something
Replies: 4
Views: 571

Re: is my pyboard broken or am i missing something

If your intention is to use a pin as combined input/output you may have to change your logic. If it is just an output, use it in OUT_OD mode.
by chuckbook
Tue Apr 03, 2018 10:23 am
Forum: MicroPython pyboard
Topic: Non-latching relay fails to deactivate
Replies: 4
Views: 568

Re: Non-latching relay fails to deactivate

Let's assume the relay works fine if Vin is at +5VDC and IN is either connected to Vin or GND. Repeat the test with Vin at 4V. If this also works fine I would recommend to use the output in open-drain mode with an external pull-up resistor connected to Vin. Note: If it is just a plain relay without ...