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PianoLED-Circle-Edition/pico/pico_sdk_import.cmake
T
prosolis 469b321a40 Port to RP2040/RP2350, extract the shared logic 
Raspberry Pi supply is unreliable, and Circle is Broadcom-only - there is no
Allwinner or Rockchip support anywhere in its tree, so an Orange Pi is not a
board swap but a restart on an unproven base. RP2040/RP2350 is the better
answer: available, ~$4, and a better fit for this job than the Zero ever was.

Structure. All the visualizer logic moves to src/ and is now
platform-independent, depending only on ILEDStrip (four methods) with MIDI
pushed in via OnMIDIPacket(). Each platform supplies a backend and a main
loop. The Circle build is unchanged in behaviour and still produces both
kernel images.

Pico backend:
- WS2812B from a PIO state machine, which clocks the 1.25us bit cell directly
  rather than faking it with 8 SPI bytes per data bit as the Circle build must.
- TinyUSB MIDI 1.0 device. Enumerates as an ordinary ALSA port, as the Circle
  gadget does. Packet framing comes from the USB MIDI Code Index Number rather
  than being re-derived.
- Mount, unmount, suspend and resume all clear held notes, so a chord held when
  the host goes away cannot stay lit.
- Latch spacing is enforced against a timestamp, so a caller cannot start a
  frame inside the WS2812B reset window.

Verified: builds clean for both pico (RP2040, 30052 bytes) and pico2 (RP2350,
28284 bytes), no warnings from project sources, and the Circle build still
produces kernel.img and kernel7.img. Tests pass across nine configurations.

Incidental findings. PIO frees both hardware SPI blocks; on a Pi Zero Circle
exposes only one SPI master (DEVICES=1 for RASPPI<4) and the WS2812B driver
monopolises it, so a display and the strip could not coexist there. RP2040/
RP2350 also support USB host and, on the W variants, BLE via btstack - both
of which section 3a records as impossible on Circle.

Also documents a known limitation found while looking at calibration: the
note-to-LED map is linear in semitone index, but a keybed is not. 52 white
keys span the same 1222mm, making one white key ~3.38 LEDs rather than 2. The
error drifts within each octave, worst at F, by up to ~0.87 LEDs (~6mm) even
after an optimal offset and scale. A geometric map would remove it. Not yet
implemented.

Claude-Session: https://claude.ai/code/session_01TVCB25LBsmeteWvaSMz4Ne
2026-08-27 22:53:00 -07:00

122 lines
5.9 KiB
CMake
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# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
# This can be dropped into an external project to help locate this SDK
# It should be include()ed prior to project()
# Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
# following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
# disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials provided with the distribution.
#
# 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
endif ()
if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
endif ()
if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
endif ()
if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_TAG} AND (NOT PICO_SDK_FETCH_FROM_GIT_TAG))
set(PICO_SDK_FETCH_FROM_GIT_TAG $ENV{PICO_SDK_FETCH_FROM_GIT_TAG})
message("Using PICO_SDK_FETCH_FROM_GIT_TAG from environment ('${PICO_SDK_FETCH_FROM_GIT_TAG}')")
endif ()
if (PICO_SDK_FETCH_FROM_GIT AND NOT PICO_SDK_FETCH_FROM_GIT_TAG)
set(PICO_SDK_FETCH_FROM_GIT_TAG "master")
message("Using master as default value for PICO_SDK_FETCH_FROM_GIT_TAG")
endif()
set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
set(PICO_SDK_FETCH_FROM_GIT_TAG "${PICO_SDK_FETCH_FROM_GIT_TAG}" CACHE FILEPATH "release tag for SDK")
if (NOT PICO_SDK_PATH)
if (PICO_SDK_FETCH_FROM_GIT)
include(FetchContent)
set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
if (PICO_SDK_FETCH_FROM_GIT_PATH)
get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
endif ()
FetchContent_Declare(
pico_sdk
GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
)
if (NOT pico_sdk)
message("Downloading Raspberry Pi Pico SDK")
# GIT_SUBMODULES_RECURSE was added in 3.17
if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
FetchContent_Populate(
pico_sdk
QUIET
GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
GIT_SUBMODULES_RECURSE FALSE
SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
)
else ()
FetchContent_Populate(
pico_sdk
QUIET
GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
GIT_TAG ${PICO_SDK_FETCH_FROM_GIT_TAG}
SOURCE_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-src
BINARY_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-build
SUBBUILD_DIR ${FETCHCONTENT_BASE_DIR}/pico_sdk-subbuild
)
endif ()
set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
endif ()
set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
else ()
message(FATAL_ERROR
"SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
)
endif ()
endif ()
get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
if (NOT EXISTS ${PICO_SDK_PATH})
message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
endif ()
set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
endif ()
set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
include(${PICO_SDK_INIT_CMAKE_FILE})
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