Search found 105 matches

by chuckbook
Thu Oct 10, 2019 9:23 am
Forum: MicroPython pyboard
Topic: THE FINAL SOLUTION: TRUE RTC ON PYBOARD
Replies: 2
Views: 112

Re: THE FINAL SOLUTION: TRUE RTC ON PYBOARD

RTC backup battery works pretty well on PYBV11 but there are some caveats: RTC driver inside MPY has a multi level fallback strategy to handle various hardware options and even HW faults if 32kHz crystal isn't installed, broken or shows a power-up delay above a certain limit, RTC clock uses LSI osci...
by chuckbook
Fri Oct 04, 2019 9:18 am
Forum: Development of MicroPython
Topic: ulab, or what you will - numpy on bare metal
Replies: 35
Views: 860

Re: ulab, or what you will - numpy on bare metal

Don't get confused about the absolute size of the code. There are a lot of additional features included. I just wanted to demonstrate code size increase for -Os and -O2.
by chuckbook
Thu Oct 03, 2019 5:15 pm
Forum: Pyboard D-series
Topic: I may have bricked I2C(2)
Replies: 13
Views: 263

Re: I may have bricked I2C(2)

If Y9 can't be used as GPIO in input and output mode there is no way it can operate in I2C mode.
As it is pretty hard to kill a GPIO port with voltages of 0V..+5V there might be a change that there is a shortcut somewhere that affects Y9.
by chuckbook
Thu Oct 03, 2019 5:03 pm
Forum: Development of MicroPython
Topic: ulab, or what you will - numpy on bare metal
Replies: 35
Views: 860

Re: ulab, or what you will - numpy on bare metal

Here are the code sizes of -O2 and -Os build options.

Code: Select all

   text    data     bss     dec     hex filename
 463704      40   28052  491796   78114 build-PYBV11_O2/firmware.elf
 424484      40   28052  452576   6e7e0 build-PYBV11/firmware.elf
by chuckbook
Thu Oct 03, 2019 3:32 pm
Forum: Pyboard D-series
Topic: I may have bricked I2C(2)
Replies: 13
Views: 263

Re: I may have bricked I2C(2)

This is exactly the reason why Y9 & Y10 don't have internal pull-ups. If PYBD is integrated in another design it is usually required to put I2C pull-up resistors on the supporting board (or even on a remote board). Using 5V as pull-up source is ok. Pull-up resistor values should be in the range of 1...
by chuckbook
Thu Oct 03, 2019 3:11 pm
Forum: Development of MicroPython
Topic: ulab, or what you will - numpy on bare metal
Replies: 35
Views: 860

Re: ulab, or what you will - numpy on bare metal

@v923z: Thanks for the info.
BTW, using our build settings (gcc version 8.2.0, -O2) the test gave 1.8ms on PYBV11.
O2 results in bigger code size but it makes sense to use it if there is some spare flash available.
by chuckbook
Thu Oct 03, 2019 2:11 pm
Forum: Pyboard D-series
Topic: I may have bricked I2C(2)
Replies: 13
Views: 263

Re: I may have bricked I2C(2)

Getting voltages above 3.3V from X15 might result from a broken LDO or some kind of shortcut to VIN. PYBD works fine even if the 3.3V LDO is broken as long as the SD card is not used! Re: I2C2 not working I2C2 works pretty well with some I2C slaves as long as very short wires are used and pull-up is...
by chuckbook
Thu Oct 03, 2019 1:56 pm
Forum: Pyboard D-series
Topic: Unexpected difference between PYBD SF2 and SF6
Replies: 6
Views: 184

Re: Unexpected difference between PYBD SF2 and SF6

Just out of curiosity:
The code example gives

Code: Select all

>>> run()
Initial
Recursive fft 0.358
Forward fft 0.077
Reverse fft 0.072
on a PYBD SF6 SP & 216 MHz
by chuckbook
Thu Oct 03, 2019 1:35 pm
Forum: Development of MicroPython
Topic: ulab, or what you will - numpy on bare metal
Replies: 35
Views: 860

Re: ulab, or what you will - numpy on bare metal

v923z wrote : I think there is a misunderstanding stemming from this post: chuckbook wrote : ↑ Fri Sep 27, 2019 1:13 pm Very impressive! Thanks for sharing this. 1k FFT (SP) in ~0.8ms on PYBD, not bad. In the original post, I quoted a measurement of 1.948 ms, and claimed that the FFT could be gotte...
by chuckbook
Sat Sep 28, 2019 4:05 pm
Forum: Development of MicroPython
Topic: ulab, or what you will - numpy on bare metal
Replies: 35
Views: 860

Re: ulab, or what you will - numpy on bare metal

I'm also astounded about the capabilities of recent compilers. It's sometimes very hard to beat them with assembler. Especially on cortex-m7 there are a lot of traps for us veteran programmers :-) However, a factor of four is quite something. I definitely will have to do some tests. Note: After look...