Search found 95 matches

by chrismas9
Thu Apr 25, 2019 4:50 am
Forum: Hardware Projects
Topic: How to expand the size of spiflash?
Replies: 7
Views: 100

Re: How to expand the size of spiflash?

The F411 does not have a hardware QSPI controller. You will need to use 1 bit SPI mode with hard or soft SPI. Have a look at STM32L476DISC port for example.
by chrismas9
Sun Apr 21, 2019 4:14 am
Forum: General Discussion and Questions
Topic: Safety of KY-019 relay
Replies: 4
Views: 86

Re: Safety of KY-019 relay

All domestic room heaters have a tilt switch and thermal cutoff that is independent of the thermostat. I suggest an independent cutout that does not rely on software. A suitable thermal cutoff is something like Digi-Key 317-1127-ND. These are available with different trip temperatures. It must be cl...
by chrismas9
Sat Apr 20, 2019 7:03 am
Forum: MicroPython pyboard
Topic: code in internal flash and mounting sd card as usb mass storage
Replies: 7
Views: 122

Re: code in internal flash and mounting sd card as usb mass storage

Have you considered using frozen byte code? The source code won't be on the system at all and will be better protected than hiding it on an non visible drive. To protect code on a non visible drive you would also have to disable REPL to stop people running their own code to read yours.
by chrismas9
Tue Apr 16, 2019 11:39 pm
Forum: MicroPython pyboard
Topic: Will 3.6 volts fry my pyboard
Replies: 2
Views: 70

Re: Will 3.6 volts fry my pyboard

Not all STM32 pins are 5V tolerant. The DAC pins PA4 and PA5 are not 5V tolerant even in digital IO mode. On some STM32s other pins are not (sometimes PA3 and maybe more). Always check the data sheet. Most analog pins, eg PA0, are 5V tolerant at reset and in digital IO mode. In ADC mode the inputs a...
by chrismas9
Tue Apr 16, 2019 11:25 pm
Forum: General Discussion and Questions
Topic: Season of Docs proposal for MicroPython
Replies: 3
Views: 119

Re: Season of Docs proposal for MicroPython

That's a great idea. I have a couple of suggestions for the library documentation. 1. Where there is a port specific additional feature add a hyperlink in the common docs to the port specific docs. That will allow you to work from the common docs without having to check the port specific docs every ...
by chrismas9
Sun Apr 14, 2019 1:22 am
Forum: General Discussion and Questions
Topic: Other Micropython forums
Replies: 3
Views: 161

Re: Other Micropython forums

High activity is not necessarily a good sign. I use a commercial PCB CAD package and its forum is alive with activity - nearly all complaints about bugs and feature changes. I find MicroPython just works and is easy to understand. I don't need to ask for help often. What is important is that there a...
by chrismas9
Sun Apr 14, 2019 1:11 am
Forum: General Discussion and Questions
Topic: best practice for erasing /flash after updating firmware
Replies: 2
Views: 79

Re: best practice for erasing /flash after updating firmware

Usually updates preserve the filesystem. However some updates affect the filesystem and you need to do a filesystem reset using the USR switch at reset. Hold down USR and press RST. After releasing RST the green and yellow LEDs will count in binary. Release USR at 3 - both LEDs on. The red LED will ...
by chrismas9
Fri Apr 12, 2019 3:52 pm
Forum: General Discussion and Questions
Topic: MicroPython Build process on Windows
Replies: 1
Views: 65

Re: MicroPython Build process on Windows

You can build using MSYS or Cygwin but by far the easiest is WSL (Windows Subsystem for Linux) under recent versions of Windows 10. Just go to Windows Store and install Ubuntu, then install tools listed in MPY readme for Ubuntu. Launch bash shell (type bash into Cortana or run box). It mounts your W...
by chrismas9
Sat Mar 23, 2019 2:38 am
Forum: Other Boards
Topic: [NUCLEO-H743ZI / STM32H743]
Replies: 4
Views: 186

Re: [NUCLEO-H743ZI / STM32H743]

You may need to reset the filesystem. On pyboard you release the USR button at 3 which is green and yellow on (binary indication of 3). On boards with not enough LEDs it is tricky to get the release time right. When you release USR st 3 the red LED will stay on for a few seconds while it erases and ...
by chrismas9
Sat Mar 23, 2019 2:13 am
Forum: MicroPython pyboard
Topic: RTC Quartz datasheet available?
Replies: 8
Views: 260

Re: RTC Quartz datasheet available?

The 32 kHz crystal is sensitive to stray capacitance and also noise. The crystal requires 6pF load. Most of this (5pF) comes from stray capacitance - PCB and STM32. Only 1pF comes from the load capacitors. Any additional stray capacitance will affect frequency. Noise is also an issue. If you place a...