Search found 147 matches

by chrismas9
Wed Mar 11, 2020 11:56 am
Forum: General Discussion and Questions
Topic: Custom Board - 32KHz Crystal
Replies: 2
Views: 186

Re: Custom Board - 32KHz Crystal

You don't need the 32kHz crystal. PYBLITE uses the same MCU in 64 pin package and the 32jHz crystal is optional. I suggest using a 12NHz main crystal and rely on the PLL to step it up to required frequency. If you have USB on your board you should be able to get a REPL prompt using the PYBLITE binar...
by chrismas9
Sat Feb 29, 2020 12:22 pm
Forum: MicroPython pyboard
Topic: STM32F446 vs STM32F405
Replies: 2
Views: 376

Re: STM32F446 vs STM32F405

PB11 is not available on the STM32F466. The pin requires a bypass cap for the internal core voltage regulator. It may not run reliability without this cap. You will need to start with the NUCLEO_F446 port and edit mpconfigport.h to suit your pin allocations. Make sure the PLL values match your cryst...
by chrismas9
Mon Feb 24, 2020 1:09 pm
Forum: Development of MicroPython
Topic: Slowing things down
Replies: 3
Views: 513

Re: Slowing things down

If you want to slow it down permanently, maybe to save power, you could edit the PLL values in moconfigboard.h and rebuild it. I suggest running the clock config utility in stm32cubemx to find the right values. Make sure the USB clock is still 48MHz if you are using USB.
by chrismas9
Wed Jan 29, 2020 11:43 pm
Forum: General Discussion and Questions
Topic: Help with motor control - Sorry I am just learning
Replies: 6
Views: 400

Re: Help with motor control - Sorry I am just learning

I like to learn by example. There are plenty of robot kits with sample code. Just search "micro:bit robot MicroPython". Here is one example:

https://github.com/KitronikLtd/micropyt ... cs?files=1
by chrismas9
Mon Jan 27, 2020 10:01 am
Forum: Other Boards
Topic: Boot time is 10 seconds for a NUCLEO_L452RE build
Replies: 4
Views: 679

Re: Boot time is 10 seconds for a NUCLEO_L452RE build

I just updated my build to latest, rebuilt mpy-cross, updated submodules and built NUCLEO_L452RE using WSL. the NUCLEO board boots immediately. I am using gcc 9.2.1 from ARM and WSL/UBUNTU 16.04. >>> MicroPython v1.12-96-gc3095b3 on 2020-01-27; NUCLEO-L452RE with STM32L452RE Type "help()" for more i...
by chrismas9
Sat Jan 25, 2020 1:24 pm
Forum: Pyboard D-series
Topic: Powering from both VUSB and microUSB
Replies: 3
Views: 451

Re: Powering from both VUSB and microUSB

VUSB feeds VIN through a diode and fuse. The safest thing to do is connect your 5V supply through another diode to VIN. That way the two diodes block any cross feed of power between your power supply and your PC's USB port, but VIN will always get power.
by chrismas9
Sat Jan 25, 2020 1:01 pm
Forum: General Discussion and Questions
Topic: SD Card Not Working - MPY: can't mount SD card
Replies: 6
Views: 391

Re: SD Card Not Working - MPY: can't mount SD card

If you are doing another run of boards it would be worth hand routing a GND track on each side of CLK.
by chrismas9
Fri Jan 24, 2020 12:24 pm
Forum: General Discussion and Questions
Topic: SD Card Not Working - MPY: can't mount SD card
Replies: 6
Views: 391

Re: SD Card Not Working - MPY: can't mount SD card

It's possible you have a crosstalk problem between CLK and CMD. On the board that works these signals change to bottom or inner layer so I can't see their routing. On the new board CLK and CMD are routed very close together for most of their run. On the pyboard there is a guard trace (GND) on each s...
by chrismas9
Tue Jan 07, 2020 1:10 pm
Forum: General Discussion and Questions
Topic: search for an inexpensive device to detect housebreaking
Replies: 19
Views: 1319

Re: search for an inexpensive device to detect housebreaking

In days of old when Wi-Fi wasn't invented and nor were PIR detectors burglar alarms had reed switches on doors and mechanical vibration switches on windows. A vibration switch could wake up a device from sleep mode.
by chrismas9
Fri Dec 27, 2019 5:11 am
Forum: General Discussion and Questions
Topic: Surface mount soldering: can anyone help with two chips?
Replies: 10
Views: 699

Re: Surface mount soldering: can anyone help with two chips?

You could try adding solder bumps to the pads like a BFA. Try to get a lump of solder 1mm high on each pad of the WSON. Then tin the PCB pads with solder. Use liquid or paste flux on the pads and place the chip. With a very fine tip melt the solder bumps and that will flow into the pads and bond. Th...