Search found 93 matches

by chuckbook
Mon Apr 01, 2019 6:44 pm
Forum: Pyboard D-series
Topic: WBUS-DIP28 backup battery possible error?
Replies: 3
Views: 294

Re: WBUS-DIP28 backup battery possible error?

The diode used was selected to provide minimal reverse current. Unfortunately this means pretty high forward voltage. Therefor a pretty low current limiting resistor has to be used. Note that the battery isn't installed as it cannot re-flowed but has to be hand soldered. It is also pretty hard to ge...
by chuckbook
Fri Mar 29, 2019 9:22 pm
Forum: Pyboard D-series
Topic: Pyboard D: Can't switch to 216 MHz
Replies: 14
Views: 862

Re: Pyboard D: Can't switch to 216 MHz

Changing CPU clock while a USB connection is active will have an impact on the data links operating via the USB interface (like the REPL). I had to toggle between 120 and 216 MHz for quite some time to force missing characters. I'm using minicom on a linux machine. Minicom is known to tolerate USB o...
by chuckbook
Tue Mar 26, 2019 8:56 am
Forum: Pyboard D-series
Topic: PYBD WBUS connector
Replies: 7
Views: 786

Re: PYBD WBUS connector

See:
https://pybd.io/hw/pybd_sfxw.html
To my knowledge there will be mating headers available on the MicroPython store.
by chuckbook
Mon Mar 25, 2019 5:18 pm
Forum: General Discussion and Questions
Topic: Comparison of the three Pyboard D models?
Replies: 6
Views: 511

Re: Comparison of the three Pyboard D models?

Only PYBD-SF3-xxxx has a high speed USB interface with integrated high speed PHY. Most if not every STM32F7xx MCU has a high speed USB interface but only F723/F733 have an integrated high speed PHY.
So if you really need high speed (480 MBaud) USB, PYBD-SF3 is the only choice.
by chuckbook
Fri Mar 22, 2019 4:08 pm
Forum: MicroPython pyboard
Topic: Speed of uart
Replies: 6
Views: 358

Re: Speed of uart

We regulary use STM32 UARTs up to 3Mbaud. I have to admit that we are also using proper 20 Mbaud differential line drivers
by chuckbook
Mon Jan 28, 2019 9:02 am
Forum: MicroPython pyboard
Topic: Necessary to connect ALL V+ & GND pins?
Replies: 2
Views: 225

Re: Necessary to connect ALL V+ & GND pins?

Using one pin for V+ & GND is ok. If V+ is used to power the PYBV11 you might consider a protective diode and some decoupling caps.
by chuckbook
Tue Jan 22, 2019 12:33 pm
Forum: MicroPython pyboard
Topic: RTC wakeup depends on calibration value ???
Replies: 2
Views: 249

Re: RTC wakeup depends on calibration value ???

If rtc.wakeup(ms, wup) is used, STM32 will always use non-calibrated RTC timer for intervals < 16s.
For intervals >= 16s the calibrated 1s timer will be used.
To force rtc.wakeup using 1s clock, use:

Code: Select all

rtc.wakeup(4, 0, wup) # 1s interval
rtc.wakeup(4, 1, wup) # 2s interval
by chuckbook
Fri Jan 11, 2019 3:54 pm
Forum: Other Boards
Topic: Looking for a board with 16 ADC channels and WiFi
Replies: 8
Views: 763

Re: Looking for a board with 16 ADC channels and WiFi

PYBD allows 16 ADC channels spread on two or three ADCs.
by chuckbook
Thu Jan 10, 2019 10:53 am
Forum: MicroPython pyboard
Topic: Save data on power down
Replies: 14
Views: 926

Re: Save data on power down

So far MicroPython uses only two of the RTC 32-bit backup registers available (20 on Pyboard, 32 on PYBD).
On a PYBV11 BKP1R..BKB18R are available for general usage.Keeping data inside RTC avoids powering backup RAM.
by chuckbook
Fri Jan 04, 2019 9:41 am
Forum: MicroPython pyboard
Topic: Save data on power down
Replies: 14
Views: 926

Re: Save data on power down

A 9V battery on MCU VBAT will destroy the MCU. Don't do this!
On a Pyboard VBAT is not MCU VBAT, I guess MCU VBAT is named VBACK on the board.
A CR2032 on VBACK is sufficient.