Search found 108 matches

by chrismas9
Wed Jan 18, 2017 11:56 am
Forum: General Discussion and Questions
Topic: Filesystem and write durability
Replies: 6
Views: 1998

Re: Filesystem and write durability

If you are writing regularly I would suggest using an SD card as they implement wear levelling which spreads the writing over the whole device instead of re-writing the same sectors. I have seen reports that some SD cards do wear levelling in the background and can be corrupted when you turn the pow...
by chrismas9
Wed Dec 07, 2016 11:29 pm
Forum: MicroPython pyboard
Topic: Pyboard pins???
Replies: 4
Views: 2047

Re: Pyboard pins???

A and D refer to Analog and Digital pins on Arduino. They both belong to a single stacking shield connector set. X and Y are different. They can be used for one large stacking board (skin) or two small ones. X1-16 and Y1-16 share the same basic pinout including Power, Ground and Reset. X has extra f...
by chrismas9
Fri Nov 11, 2016 4:41 pm
Forum: Development of MicroPython
Topic: RFC: Hardware API: finalising machine.Pin
Replies: 62
Views: 15509

Re: RFC: Hardware API: finalising machine.Pin

pin.value() is undefined for PIN.OUT and when PIN.OPEN_DRAIN is low but defined when it is open drain high (floating). I use open drain pins in various ways including wire OR'd busy/ready synchronising between multiple devices, bidirectional multidrop 1 pin serial links and soft I2C. In many cases i...
by chrismas9
Sun Oct 23, 2016 2:59 am
Forum: Development of MicroPython
Topic: RFC: Hardware API: finalising machine.Pin
Replies: 62
Views: 15509

Re: RFC: Hardware API: finalising machine.Pin

Sorry I digressed from Pin. Back to Pin. +1 for toggle and/or pin.out_value() and open drain. Do we need pin.out_value() to get the output buffer value of a pin? • I didn't even realise that pin.toggle() was specified in these specs :) Do we need it? It's listed in the specs as "optional" but I thin...
by chrismas9
Sat Oct 22, 2016 5:48 pm
Forum: Development of MicroPython
Topic: RFC: Hardware API: finalising machine.Pin
Replies: 62
Views: 15509

Re: RFC: Hardware API: finalising machine.Pin

Let's discuss something. I wonder if I'm the only one who ever wondered why there's no LED class in Hardware API? And here's the question - do we want to deal with inverted signals? And using word "signal" actually suggests the right way to deal with it from OO perspective: LED = machine.Signal(mac...
by chrismas9
Sun Oct 16, 2016 11:20 am
Forum: General Discussion and Questions
Topic: Pyboard noise
Replies: 21
Views: 7227

Re: Pyboard noise

2 PIN POWER SUPPLIES @pythoncoder @gratefulfrog The leakage current from unearthed power supplies does kill semiconductors but it should be safe for people. Almost all power supplies have a 4n7 cap from the 200V / 400V DC negative to the output negative. That's about 600k to 700k at 50/60Hz. That's ...
by chrismas9
Sun Oct 16, 2016 9:48 am
Forum: General Discussion and Questions
Topic: Pyboard noise
Replies: 21
Views: 7227

Re: Pyboard noise

@greatfulfrog @dhylands @ pythoncoder Thanks for the comments. I have edited the typos and added an extra bit about GND planes and some clarification. moral of the story - don't type in front of Netfix, don't type after midnight and don't trust orto korekt. Part of the motivation for writing this is...
by chrismas9
Sat Oct 15, 2016 2:13 pm
Forum: General Discussion and Questions
Topic: Pyboard noise
Replies: 21
Views: 7227

Re: Pyboard noise

Hi Bob, @roberthh and @pythoncoder give good advice about grounding and using a star ground. This is not always enough. It helps to understand all the ways noise can get into sensitive circuits. I do a lot of mixed signal design and I will explain how I analyse noise sources and optimise PCB layouts...
by chrismas9
Sun Aug 28, 2016 1:41 am
Forum: MicroPython pyboard
Topic: connecting pyboard to CAN BUS
Replies: 45
Views: 17391

Re: connecting pyboard to CAN BUS

I use the Microchip MCP series DIP CAN transceivers regularly with STM32. They are a 5V device but fully compatible with 5V tolerant 3.3V MCU's. No level translator is required. The transmitter input requires <0.8V and >2V for logic 0 and 1 respectively which the STM32 can do. The receiver output gi...
by chrismas9
Sun Aug 28, 2016 1:26 am
Forum: MicroPython pyboard
Topic: Unstable value when use analog imput on pyboard v 1.1
Replies: 3
Views: 1803

Re: Unstable value when use analog imput on pyboard v 1.1

A good test would be to run the Pyboards off 3 or 4 Alkaline cells (4.5V - 6V). If the analog results are good for both boards your power supply is noisy. Pybv1.1 requires slightly higher voltage on Vin and may be more susceptible to switching spikes from a switch mode power supply. The changes to t...