HP HSTNS-PL30 DIY Raspberry Pi Pico Watt Meter

Build on Mac OS

1. Create an Anaconda virtual environment (Python >= 3.12, required by Zephyr v4.4.0)
   Download Anaconda for Mac(Intel)
   conda create -n zephyr python=3.12 && conda activate zephyr

2. Installing Dependencies
   brew install cmake dtc

3. Install West
   pip install west

4. Initialize Zephyr(Tag: v4.4.0)
   west init --mr v4.4.0 ~/zephyrproject
   cd ~/zephyrproject
   west update
   pip install -r ~/zephyrproject/zephyr/scripts/requirements.txt

5. Setting Up the Toolchain
   macOS (x86_64) hosted cross toolchains AArch32 13.2.Rel1
   export ZEPHYR_TOOLCHAIN_VARIANT=gnuarmemb
   export GNUARMEMB_TOOLCHAIN_PATH=~/zephyrproject/arm-gnu-toolchain-13.2.Rel1-darwin-x86_64-arm-none-eabi

6. Clone repo
   git clone https://github.com/darwinbeing/zpsu_mon.git ~/

7. Compile
   cd ~/zpsu_mon
   source ~/zephyrproject/zephyr/zephyr-env.sh

   Pico RP2040 Display Pack
   west build -b rpi_pico -d build_lcd1 -- -DCONFIG_PICO_DISPLAY_PACK=y

   Pico RP2040 Display Pack2
   west build -b rpi_pico -d build_lcd2 -- -DCONFIG_PICO_DISPLAY_PACK2=y

   Pico2 RP2350A Display Pack
   west build -b rpi_pico2/rp2350a/m33 -d build_lcd3 -- -DCONFIG_PICO_DISPLAY_PACK=y

   Pico2 RP2350A Display Pack2
   west build -b rpi_pico2/rp2350a/m33 -d build_lcd4 -- -DCONFIG_PICO_DISPLAY_PACK2=y

   Pico W RP2040 WiFi (one-time first: cd ~/zephyrproject && west blobs fetch hal_infineon)
   west build -b rpi_pico/rp2040/w -d build_wifi -- -DCONFIG_PICO_DISPLAY_PACK2=y -DEXTRA_CONF_FILE=wifi.conf

   Pico W RP2040 AP (mutually exclusive with wifi.conf; same one-time blob fetch as above)
   west build -b rpi_pico/rp2040/w -d build_ap -- -DCONFIG_PICO_DISPLAY_PACK2=y -DEXTRA_CONF_FILE=ap.conf The AP (zpsu- / zpsu1234, 192.168.4.1) auto-starts at boot; PSU control over UDP :5000 — nc -u 192.168.4.1 5000 then STATUS/ON/OFF/MODE CC/CC 5.0/FAN, or python3 psu_ap_smoke.py

   SoftAP shell commands (over the USB-CDC console): wifi ap enable -s "" -k 1 -p "" -c 6 start the AP (-k 1 = WPA2-PSK) wifi ap disable stop the AP wifi ap status AP state wifi ap stations list connected clients apset persist new AP creds + re-enable printf 'SETAP \n' | nc -u 192.168.4.1 5000 same, over UDP :5000

   Software-triggered USB firmware upgrade (opt-in CONFIG_APP_USB_DFU; no button) west build -b rpi_pico/rp2040/w -d build_dfu --
   -DCONFIG_PICO_DISPLAY_PACK2=y -DEXTRA_CONF_FILE="wifi.conf;dfu.conf" Trigger from the running app -> device drops into the RP2040 USB BOOTSEL bootloader (bootrom reset_usb_boot()), then upgrade over USB (no MCUboot/repartition/signing): trigger shell dfu | UDP printf 'DFU\n' | nc -u 192.168.4.1 5000 | hold A+Y 2 s upgrade picotool load -x build_dfu/zephyr/zephyr.uf2 (or drag the .uf2 to RPI-RP2) Note: after the flash-reboot the USB-CDC console may need one unplug/replug to re-enumerate on macOS (RP2040+host USB quirk; the upgrade itself always succeeds). Design + findings: docs/superpowers/specs/2026-06-08-usb-dfu-upgrade-design.md

   SoftAP fix (Zephyr v4.4.0): the Infineon AIROC/WHD 3.3.3 firmware rejects the "chanspec" iovar in AP mode with WHD_WLAN_BADCHAN (2020) on every 2.4 GHz channel (whd_wifi_init_ap -> whd_wifi_set_chanspec), so SoftAP bring-up failed on v4.4.0 (it worked on v4.2.1/WHD 3.3.2). Fixed by patches/cyw43439_ap_set_channel.patch: whd_wifi_init_ap now sets the channel via the WLC_SET_CHANNEL ioctl (plain channel number, exactly as the Pico SDK cyw43-driver SoftAP does) for the 43439, instead of the chanspec iovar. Apply for local builds (from this repo root): git -C ~/zephyrproject/modules/hal/infineon apply "$PWD/patches/cyw43439_ap_set_channel.patch" (verified on hardware: AP zpsu-<MAC4> broadcasts and clients associate).

Runtime WiFi/AP credentials (persist in flash, no rebuild)

Credentials live in NVS (a flash storage_partition), so you set them once at runtime instead of baking them into the image:

Required patch: patches/rp2040_flash_ramfunc.patch (applied by CI; apply manually from this repo root: git -C ~/zephyrproject/modules/hal/rpi_pico apply "$PWD/patches/rp2040_flash_ramfunc.patch"). It fixes the real cause of Zephyr #68728: three hardware_flash/flash.c helpers (flash_wait_ready, flash_enable_write, flash_put_cmd_addr) are static inline without the RAM attribute, so when the compiler doesn't inline them they sit in XIP flash and are called while XIP is disabled → HardFault → double fault → MCU lockup the first time a credential is saved. The patch forces them into RAM (__no_inline_not_in_flash_func).

STA (join your WiFi): over the USB-CDC shell, then reboot —
  wifi cred add -s "<ssid>" -k 1 -p "<psk>"          (-k 1 = WPA2-PSK)
  wifi cred list / wifi cred delete -s "<ssid>"       (manage stored networks)

AP (rename/secure the SoftAP): while joined to the AP, over UDP :5000 —
  printf 'SETAP <ssid> <psk>\n' | nc -u 192.168.4.1 5000   (psk 8-63 chars)
  or over the USB-CDC shell:  apset <ssid> <psk>
The AP re-enables with the new creds (it drops you — rejoin with them).

Optional build-time seed: a gitignored src/net/wifi_creds.h / src/net/ap_creds.h is written to the store once on first boot when it is empty; runtime changes override thereafter. With no seed and nothing stored, the STA waits for a wifi cred add and the AP falls back to zpsu-<MAC4> / zpsu1234.

Pico W (WiFi STA) boot log + gateway ping

USB-CDC console of the build_wifi image (board rpi_pico/rp2040/w, Zephyr v4.4.0, SSID redacted): the AIROC CYW43439 starts, the STA associates, DHCPv4 leases an address, then net ping to the gateway returns 5/5. (The log begins where the USB-CDC console enumerates, ~4 s after power-on, so the early boot banner is not shown.)

[4050] WLAN MAC Address : D8:3A:DD:FE:98:13
[4056] WLAN Firmware    : wl0: Jun  5 2024 06:33:59 version 7.95.88 (cf1d613 CY) FWID 01-7b7cf51a
[4062] WLAN CLM         : API: 12.2 Data: 9.10.39 Compiler: 1.29.4 ClmImport: 1.36.3 Creation: 2024-04-16 21:20:55
[4064] WHD VERSION      : 3.3.3.26653 : WIFI5-v3.3.3 : GCC 13.2 : 2025-04-14 03:18:50 +0000
[00:00:04.583,000] <wrn> udc_rpi: BUS RESET
PWM-based RGB LED control
[00:00:04.703,000] <wrn> display_control: Display regulator control not supported
[00:00:07.717,000] <inf> wifi_net: auto-connecting to "<your-ssid>" ...
[00:00:10.660,000] <inf> wifi_net: WiFi associated; starting DHCPv4
[00:00:15.092,000] <inf> wifi_net: WiFi up: 192.168.1.191 gw 192.168.1.1
uart:~$ kernel version
Zephyr version 4.4.0
uart:~$ net ping -c 5 192.168.1.1
PING 192.168.1.1
28 bytes from 192.168.1.1 to 192.168.1.191: icmp_seq=1 ttl=64 time=19 ms
28 bytes from 192.168.1.1 to 192.168.1.191: icmp_seq=2 ttl=64 time=12 ms
28 bytes from 192.168.1.1 to 192.168.1.191: icmp_seq=3 ttl=64 time=12 ms
28 bytes from 192.168.1.1 to 192.168.1.191: icmp_seq=4 ttl=64 time=12 ms
28 bytes from 192.168.1.1 to 192.168.1.191: icmp_seq=5 ttl=64 time=15 ms