MicroPython Forum (Archive)

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...

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.

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.

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

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...

@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.

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...

Just out of curiosity:
The code example gives on a PYBD SF6 SP & 216 MHz

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...

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...