Join Scott today as he answers questions, talks about fixing for CircuitPython 7.0.0 and dives deep into system on a chip datasheet diagrams.

Scott is sponsored by Adafruit to work on CircuitPython. Support them by purchasing hardware from https://adafruit.com

Chat with Scott and lot of others on the Adafruit Discord at https://adafru.it/discord.

Deep Dive happens every week. Next week is on Friday.

0:00:00 Hellos

0:02:50 Morpheus240 esp32-s2 board. at this point its more of a copy something else process

0:05:45 housekeeping hello everyone

0:09:09 Does circuitpython run on esp8266 or 32? ( also transition into BLE workflow )

0:13:10 BLE work team members

0:14:14 Which BLE devices do you expect to support?

0:15:38 What about on OTA (over the air update) devices?

0:17:02 Can the boards you are programming today access the internet?

0:17:36 reddit / AMA - https://www.reddit.com/r/Python/comments/oyrqp0/welcome_to_a_joint_ama_with_some_of_the/

0:19:00 Would micropython run into GIL like issues? (GIL: Global Interpreter Lock)

0:21:24 go over the MP_STATE_VM stuff and when to use it instead of global variable declaration... the context being your review comment on the atexit PR #5077 - https://github.com/adafruit/circuitpython/pull/5077/files

0:24:20 “what is memory allocation”

BSS: (start at zero )/ data: / heap: malloc / realloc , stack:

0:29:15 Fish / OhMyZsh / OhMyFish?

0:30:20 Circuit Python can not defrag

0:31:30 import / long lived packing more densely / generational garbage collection - https://en.wikipedia.org/wiki/Garbage_collection_(computer_science)

0:32:40 reference counting / determining when memory is not used

0:33:35 MP/CP mark and sweep / garbage collection

0:35:40 Does Python have garbage collection?

0:36:50 also look in MP_STATE

0:38:00 ( future desire - look at rust to get memory protection ) - https://en.wikipedia.org/wiki/Rust_(programming_language)

0:39:30 “Python - learn things as you need them”

0:40:15 Globals don’t get “marked”

0:42:25 gc_collect_start

0:45:07 bug from last week PyOCD ( UF2 bootloader broken if greater than 512K)

0:47:00 NRF boot loader issue issue Adafruit_nRF52_Bootloader 213 ( use 0.6.1 )

0:50:06 binutils update to get bug fixes too ( linker output bogus debug data)

0:52:35 Have you used Wokwi? It's a web based simulator with a really nice gui showing circuits. It's at https://wokwi.com/

0:54:00 Difference between simulators and ‘real’ hardware devices

0:55:45 Simulators may provide opportunities for automated regression testing

0:57:30 Monico editor ?

0:58:00 Rosie test tool in previous editor + cat on shredder distraction

1:00:30 Can you put a fitbit on your cat and be notified when he has a seizure..?

1:01:55 using scale under the litterbox to weigh the cats

1:05:30 corrupts auto-reload, and other things on Circuit Playground Express 3890

SAMD21 tucks per event Pull #5100 - https://github.com/adafruit/circuitpython/issues/3890

1:12:00 review SAM D21 block diagram - http://ww1.microchip.com/downloads/en/DeviceDoc/SAM_D21_DA1_Family_DataSheet_DS40001882F.pdf

1:16:23 Advanced Microcontroller Bus Architecture - https://en.wikipedia.org/wiki/Advanced_Microcontroller_Bus_Architecture

1:17:20 “need to understand the whole system, not just the CPU”

1:19:50 peripherals

1:20:40 ​Can RAM in micro controllers be accessed similar to PEEK and POKE in C64 Basic?

1:21:15 memory mapped peripherals DMA - Direct Memory Access

1:23:58 Events / Interrupts / NVIC Nested Vector Interrupt Controller

1:28:05 Can time trigger an interrupt?

1:28:50 Convert events into interrupts

1:29:35 How long does the interrupt take to fire and load into state/what's the resolution of it?

1:31:50 ​Generators vs Users creating and consuming events or interrupts.

1:33:00 Event Detected - convert an event into an interrupt ( PR #5100 )

1:34:16 PR 5100 code files

1:38:20 decoding interrupt event

1:40:05 NTP to set a RTC and then compared the RTC to NTP 24 hours later and found out the RTC was gaining 7 secs/day

1:41:00 The volatile keyword

1:42:53 RP2040 block diagram - https://datasheets.raspberrypi.org/rp2040/rp2040-datasheet.pdf

1:49:40 SAM D51 block diagram - https://www.microchip.com/content/dam/mchp/documents/MCU32/ProductDocuments/DataSheets/SAM_D5x_E5x_Family_Data_Sheet_DS60001507G.pdf

1:54:25 Can you use DMA between Neopixels and i2c on any CP targets ?

1:55:35 NeoPixels can have their data ‘exploded’ to improve timing

1:56:45 ​Are these Micro Controllers optimized for bus length between CPU and RAM? Or are there other items that have a higher priority for bus speed?

1:57:33 SAM D Memory mapping overview

1:58:48 Cypress (now Infineon) PSoC chips

1:59:24 NXP Simplified Block Diagram - https://www.nxp.com/docs/en/data-sheet/IMXRT1010CEC.pdf

2:00:50 Cortex-M7 Platform diagram ( from reference manual )

2:03:30 STM32H7B0xB block diagram - https://www.st.com/resource/en/datasheet/stm32h7b0ib.pdf

2:10:45 wrap up

2:12:45 Have a great weekend - c u next friday