🌿 SUDI Keyboard V2

Sudi V2 is custom wireless split keyboard based on NRF52832 Nordic Semiconductor Microcontroller series, each side consist 18 keys 36 in totals, use MCP23017 I2C I/O expansion to scan one side of keyboard, and use wire to trasfer data to NRF52. Built in SWD debug port, with Serial Logger based on CH340G. Sudi Have interactive RGB LED and OLED 0.91 inch for graphic display. Planned to create 3D print enclosure.

🖨️ Compile And Flash

🍮 Step to Compile and flash (Zephyr)

first activate your python environtment (i use micromamba, sudiv2 is environtment on my linux pc)

micromamba activate sudiv2

next build with west

west build -b sudi app

---

🍮 Step to Compile and flash (Makefile and Native toolchain)

1. because we use makefile just call make in root directory
2. after complete you can use jlink or stlink to program your binary, nrf can programmed with swd
3. to use jlink you can use this command sudo JLinkExe -Device NRF51822_XXAA -IF swd -AutoConnect 1 -Speed 1000 then you can load binary file with loadfile ./path/to/file.out (we use .out instead .elf)
4. to use stlink you can use this script you need change .out path

#!/bin/bash
openocd -f openocd.cfg -c "init" \
  -c "halt" \
  -c "nrf51 mass_erase" \
  -c "program ./build/binary.out verify reset exit"

🐞 Debugging Step

there is many way to debug NRF microcontroller, i will use JLink V8. first connect Jlink SWD to NRF MCU.

after compile, upload your binary with jlink

 sudo JLinkExe -Device NRF51822_XXAA -IF swd -AutoConnect 1 -Speed 1000 // change device based on your device

next inside JLinkExe run load binary file with loadfile ./path/to/your/file.elf (you can automate this with text script, but i just want write it to remember).

then start openocd debug server with

sudo openocd -f interface/jlink.cfg  -c "transport select swd; adapter speed 1000" -f target/nrf51.cfg &

finally you can start your debugger in this case we use arm-none-eabi-gdb then connect to target with this step (withtout >)

> file ./path/to/your/file.elf
> break main.c:22 //optional
> target extended-remote :3333 // default port for openocd debug server
> // devices connected

if debugger will stuck on fail.c after arch interrupt lock there maybe some bad/wrong setting(recheck your config).

🍷 Old Debug Step (here for history purpose only)

to debug you can use openocd + stlink, openocd + jlink, ozone. make sure to change gdbcmd.txt based on your setting (gdb port, output filename, etc.)

//🗒️🗒️🗒️🗒️ gdbcmd.txt 🗒️🗒️🗒️🗒️🗒️
// you need to connect into server first before choosing `file` to debug, 
target extended-remote :3333
file ./build/nrf51822_xxaa.out
break main
continue

• openocd + stlink first start openocd gdb server with this command

  sudo openocd -f interface/stlink-v2.cfg -f target/nrf51.cfg &

next you can use arm-none-eabi-gdb to debug your program, run this command on other terminal arm-none-eabi-gdb -x gdbcmd.txt

• openocd + jlink you can start jlink gdb server with this command sudo JLinkGDBServerExe & then choose device and peripheral (swd) , or you can start server with openocd

 sudo openocd -f interface/jlink.cfg  -c "transport select swd; adapter speed 1000" -f target/nrf51.cfg

next you can use arm-none-eabi-gdb to debug your program, run this command on other terminal arm-none-eabi-gdb -x gdbcmd.txt

• ozone last option you can use segger ozone. (not trying yet)

expand this if you curious (historic purpose only)

• Ok!!, I need 2 days (on my weekend) for figuring out how compile in NRF51 mcu with NRF5 SDK (at time of writing NRF5 SDK was obsolete/under maintenance only by Nordic Semiconductor).

• FIRST as far as i understand NRF51 MCU series only work with NRF5 sdk below version 12 (never complete compiling with version above 12), so you need to download NRF5 SDK version 12 or below.

• SECOND i have try to compile nrf project with cmake, but fail and make me stress, so i stick with makefile

• THIRD debugging with arm-eabi-none-gdb a bit tricky you need perform several command before program go into breakpoint.

• FOURTH you need to use old gcc compiler (gcc-arm-none-eabi-4_9-2015q3-20150921-linux.tar.bz2), there is some problem in linking process when you use new gcc version like v14

💾 hardware

hardware is designed with Kicad, you can find out hardware design in pcb-design folder.

casing is designed with PTC CREO, and use cutting acrylic (not uploaded/complete yet but planned)

Expand Me

🧁 Install Module In Zephyr

zephyr use manifest(west.yml) to setting what module used. to automatic install module, add module name after name-allowlist, here is example.

manifest:
  self:
    west-commands: scripts/west-commands.yml

  remotes:
    - name: zephyrproject-rtos
      url-base: https://github.com/zephyrproject-rtos

  projects:
    - name: zephyr
      remote: zephyrproject-rtos
      revision: main
      import: 
        name-allowlist:
          - cmsis      # required by the ARM port
          - hal_nordic # required by the custom_plank board (Nordic based)
          - hal_stm32  # required by the nucleo_f302r8 board (STM32 based)
          - segger # add another component based on module repository

after edit west.yml run west update, west will update the module based on manifest.

west will search to this repo, then download and install it based on your zephyr root.

after you installed (download) zephyr module you can enable with menuconfig, you can run menuconfig with

west build -t menuconfig

🧱 TODO List

• try to understand why linker script flash ram address need to change from 0x8000 to 0x4000 look this thread, use Zephyr instead.
• update hardware readme.md section, add schematic svg
• try to logging with segger jlink rtt at 9 september 2024 22:09
• try to logging with serial logger
• add usb to serial (ch340g) if serial logger worked /or considering to use segger rtt (worked and tested on NRF51822)
• add on off switch for board
• 🦀 Change design to use NRF52832
• 🔥 Learn more about Zephyr
• change JTAG debugger to component with less space and same pinout based on JLink v8 pinout.
• 🔋 battery/and its charger need adjustment, because NRF5232 power supply range is 1.7 V to 3.6 V , and TP4056 will shutdown on 4.2V. if you add AMS1117 3.3v to regulate it, AMS1117 need at least 4.5V to maintain its 3.3V. (NAH, use buck boost instead)
• 🔋 read about BQ24075 bms datasheet
• 🔋 Read about MAX17048 datasheet
• 🔋 if we use 1.8V for NRF Voltage supply, how its affect other used component
  • 🪔 WS2812 VIO level was not satisfied, based on its datasheet, min supply is 3.5, VIH 0.7*VDD (2.45), VIL 0.3 *VDD (1.05)
  • ⚗️ based on MCP23017 datashet its power voltage range is 1.8V to 5.5v, VIH 0.25 VDD + 0.8, VIL 0.8 VDD, so its possible to use MCP23017 with 1.8V NRF voltage supply,
  • 🐤 CH340G
• 🔶check 4 pin crystal compatibility
• 🦄 change MCU to use NRF52833?? (power supply 1.7-5.5), usb, price +1 dollar 😥, or (NRF52820 only $2.6348)
• 🧀 Recheck Silk Screen and componnent
• 💸 Create Manufacture id BOM, and Order it about 70 dollar
• 💸 wait dollar until it lower, and order all needed component. shit!!!, dollar does not decline
• ⚽ Final Re-Inspection not doing it actually
• 💸 ordered pcb. 5 Pcs for $15.72 with shipment 7.02 dollar and the pcb is 8.7, still wait for tax. ⏰ 19 januari 2025 at 22:16

💳 Reference

• you need to read this if blink example not working
• NRF51 Series Documentation
• Redox-Keyboard i use redox schematic for initial design
• MCP23017 datasheet and add my initial redox sch with MCP23017
• Zephyr Devices Tree
• Buck Boost for 3.3v

^{🔥 make it V2 - 19 juni 2024 10:49}