From c02ec01f755f20d9edaf81112be957232acf7b07 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mikael=20L=C3=B6vqvist?= Date: Tue, 17 Feb 2026 23:54:13 +0100 Subject: [PATCH] Initial commit --- .gitignore | 2 + basic-udp/CMakeLists.txt | 26 ++++ basic-udp/lwipopts.h | 37 +++++ basic-udp/main.c | 81 +++++++++++ basic-udp/pico_sdk_import.cmake | 121 ++++++++++++++++ basic-udp/readme.md | 128 ++++++++++++++++ basic-udp/udp-dump.py | 14 ++ i2c-over-tcp/plans.md | 39 +++++ tcp-command-frame/CMakeLists.txt | 26 ++++ tcp-command-frame/client.mjs | 58 ++++++++ tcp-command-frame/lwipopts.h | 37 +++++ tcp-command-frame/main.c | 185 ++++++++++++++++++++++++ tcp-command-frame/pico_sdk_import.cmake | 121 ++++++++++++++++ tcp-command-frame/readme.md | 60 ++++++++ 14 files changed, 935 insertions(+) create mode 100644 .gitignore create mode 100644 basic-udp/CMakeLists.txt create mode 100644 basic-udp/lwipopts.h create mode 100644 basic-udp/main.c create mode 100644 basic-udp/pico_sdk_import.cmake create mode 100644 basic-udp/readme.md create mode 100644 basic-udp/udp-dump.py create mode 100644 i2c-over-tcp/plans.md create mode 100644 tcp-command-frame/CMakeLists.txt create mode 100644 tcp-command-frame/client.mjs create mode 100644 tcp-command-frame/lwipopts.h create mode 100644 tcp-command-frame/main.c create mode 100644 tcp-command-frame/pico_sdk_import.cmake create mode 100644 tcp-command-frame/readme.md diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..083f581 --- /dev/null +++ b/.gitignore @@ -0,0 +1,2 @@ +secrets/ +build/ \ No newline at end of file diff --git a/basic-udp/CMakeLists.txt b/basic-udp/CMakeLists.txt new file mode 100644 index 0000000..5b35059 --- /dev/null +++ b/basic-udp/CMakeLists.txt @@ -0,0 +1,26 @@ +cmake_minimum_required(VERSION 3.13) + +set(PICO_BOARD pico_w) +include(pico_sdk_import.cmake) + +project(pico_w_udp_client C CXX ASM) +set(CMAKE_C_STANDARD 11) + +pico_sdk_init() + +add_executable(pico_w_udp_client + main.c +) + +target_include_directories(pico_w_udp_client PRIVATE + ${CMAKE_CURRENT_LIST_DIR} + ${CMAKE_CURRENT_LIST_DIR}/../secrets +) + +target_link_libraries(pico_w_udp_client + pico_stdlib + pico_cyw43_arch_lwip_poll + pico_lwip_nosys +) + +pico_add_extra_outputs(pico_w_udp_client) diff --git a/basic-udp/lwipopts.h b/basic-udp/lwipopts.h new file mode 100644 index 0000000..d30449f --- /dev/null +++ b/basic-udp/lwipopts.h @@ -0,0 +1,37 @@ +#ifndef LWIPOPTS_H +#define LWIPOPTS_H + +/* Platform */ +#define NO_SYS 1 +#define LWIP_SOCKET 0 +#define LWIP_NETCONN 0 +#define LWIP_TIMEVAL_PRIVATE 0 + +/* Memory */ +#define MEM_ALIGNMENT 4 +#define MEM_SIZE (8 * 1024) +#define MEMP_NUM_PBUF 16 +#define MEMP_NUM_UDP_PCB 4 +#define MEMP_NUM_TCP_PCB 4 +#define MEMP_NUM_TCP_PCB_LISTEN 4 +#define MEMP_NUM_SYS_TIMEOUT 8 + +/* Pbufs */ +#define PBUF_POOL_SIZE 16 +#define PBUF_POOL_BUFSIZE 1520 + +/* IP */ +#define LWIP_IPV4 1 +#define LWIP_IPV6 0 +#define LWIP_ICMP 1 +#define LWIP_DHCP 1 +#define LWIP_UDP 1 +#define LWIP_TCP 1 + +/* Checksums */ +#define CHECKSUM_BY_HARDWARE 1 + +/* Debug */ +#define LWIP_DEBUG 0 + +#endif /* LWIPOPTS_H */ diff --git a/basic-udp/main.c b/basic-udp/main.c new file mode 100644 index 0000000..bf89239 --- /dev/null +++ b/basic-udp/main.c @@ -0,0 +1,81 @@ +#include + +#include "pico/stdlib.h" +#include "pico/cyw43_arch.h" + +#include "lwip/netif.h" +#include "lwip/udp.h" +#include "lwip/pbuf.h" +#include "lwip/ip_addr.h" +#include "lwip/dhcp.h" + +#include "wifi-settings.h" + +static struct udp_pcb *udp; +static ip_addr_t dest_ip; + +extern struct netif *netif_default; + +static void send_hello(void) { + const char msg[] = "hello world\n"; + + struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, sizeof(msg) - 1, PBUF_RAM); + if (!p) { + return; + } + + memcpy(p->payload, msg, sizeof(msg) - 1); + udp_sendto(udp, p, &dest_ip, 5505); + pbuf_free(p); +} + +int main() { + stdio_init_all(); + + if (cyw43_arch_init()) { + return -1; + } + + cyw43_arch_enable_sta_mode(); + + if (cyw43_arch_wifi_connect_timeout_ms( + WIFI_SSID, + WIFI_PASS, + CYW43_AUTH_WPA2_AES_PSK, + 30000)) { + return -1; + } + + /* Raw lwIP setup */ + udp = udp_new_ip_type(IPADDR_TYPE_V4); + if (!udp) { + return -1; + } + + ipaddr_aton("192.168.2.99", &dest_ip); + + absolute_time_t next = get_absolute_time(); + + bool dhcp_done = false; + + while (true) { + cyw43_arch_poll(); + + if (!dhcp_done) { + if (netif_default && + netif_is_up(netif_default) && + !ip4_addr_isany_val(*netif_ip4_addr(netif_default))) { + + dhcp_done = true; + cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1); + } + } + + if (absolute_time_diff_us(get_absolute_time(), next) <= 0) { + send_hello(); + next = delayed_by_ms(next, 1000); + } + + sleep_ms(1); + } +} diff --git a/basic-udp/pico_sdk_import.cmake b/basic-udp/pico_sdk_import.cmake new file mode 100644 index 0000000..d493cc2 --- /dev/null +++ b/basic-udp/pico_sdk_import.cmake @@ -0,0 +1,121 @@ +# This is a copy of /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}) diff --git a/basic-udp/readme.md b/basic-udp/readme.md new file mode 100644 index 0000000..9d9ad23 --- /dev/null +++ b/basic-udp/readme.md @@ -0,0 +1,128 @@ +# Raspberry Pi Pico W – Minimal Wi-Fi UDP Example (Arch Linux) + +## Authorship + +This document was generated using ChatGPT (OpenAI), version 5.2. +It has not been independently reviewed or validated yet. + +## Purpose + +Minimal Pico W Wi-Fi example using the Arch Linux packaged Pico SDK. +Goal: clean build, no hidden assumptions, raw lwIP usage. + +--- + +## Environment + +* Arch Linux +* `pico-sdk` from `/usr/share/pico-sdk` +* Board: Pico W +* Toolchain: `arm-none-eabi-gcc` +* lwIP in `NO_SYS` mode +* Driver: `pico_cyw43_arch_lwip_poll` + +--- + +Add the following sections. + +--- + +## Build + +```sh +mkdir build +cd build +cmake .. +make -j +``` + +Explanation: + +* `cmake ..` configures the project and generates build files. +* `make -j` builds using all available CPU cores. +* After configuration, normal source changes require only `make -j`. +* If `CMakeLists.txt` changes, delete the `build/` directory and run `cmake` again. + +The resulting firmware file: + +``` +build/pico_w_udp_client.uf2 +``` + +--- + +## Flash + +```sh +picotool load -f pico_w_udp_client.uf2 +``` + +This writes the UF2 image to the Pico W over USB (device must be in BOOTSEL mode or rebooted via picotool). + +--- + +## Runtime Behavior + +After flashing and reset: + +1. The Pico W connects to the configured Wi-Fi network. +2. Once DHCP assigns an IP address, the onboard LED turns on. +3. The device begins sending periodic `hello world` UDP messages to the configured destination IP address. + + +## CMake Configuration + +Board is selected in `CMakeLists.txt`: + +```cmake +set(PICO_BOARD pico_w) +include(pico_sdk_import.cmake) +``` + +Wi-Fi credentials are kept outside the main source tree: + +```cmake +target_include_directories(pico_w_udp_client PRIVATE + ${CMAKE_CURRENT_LIST_DIR} + ${CMAKE_CURRENT_LIST_DIR}/../secrets +) +``` + +Example usage: + +```c +#include "secrets/fra.h" +``` + +This keeps credentials separate from firmware logic. + +--- + +## Networking Model + +* lwIP raw API (UDP) +* `NO_SYS = 1` +* Explicit polling via `cyw43_arch_poll()` +* Project-local `lwipopts.h` + +No sockets, no netconn, no `sys_arch`, no background threads. + +--- + +## Key Points + +* Arch SDK requires providing your own `lwipopts.h`. +* Sockets require `NO_SYS = 0` and a `sys_arch` implementation — not used here. +* Raw API is the simplest and fully self-contained option. +* TCP/UDP framing must be handled at application level. + +--- + +## Result + +✔ Builds cleanly +✔ Pico W connects to Wi-Fi +✔ UDP packets transmitted +✔ Deterministic configuration + + diff --git a/basic-udp/udp-dump.py b/basic-udp/udp-dump.py new file mode 100644 index 0000000..cf696fc --- /dev/null +++ b/basic-udp/udp-dump.py @@ -0,0 +1,14 @@ +import socket, time + +UDP_IP = "192.168.2.99" +UDP_PORT = 5505 + +sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) +#sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1) +sock.bind((UDP_IP, UDP_PORT)) + +print(f"Listening on UDP port {UDP_PORT}...") + +while True: + data, addr = sock.recvfrom(1024) + print(f"{time.ctime()} [{addr[0]}:{addr[1]}] {data.decode('utf-8', errors='replace')}") diff --git a/i2c-over-tcp/plans.md b/i2c-over-tcp/plans.md new file mode 100644 index 0000000..03a80ca --- /dev/null +++ b/i2c-over-tcp/plans.md @@ -0,0 +1,39 @@ +# TCP → I2C bridge + +## Authorship + +This document was generated using ChatGPT (OpenAI), version 5.2. +It has not been independently reviewed or validated yet. + +# Translation units + +## `i2c_controller.c` + +* `i2c_handle_frame(cmd, payload, len, reply_buf, *reply_len)` +* No transport knowledge. +* Pure logic + hardware calls. + + +## `usb_transport.c` + +* Parses frames from CDC. +* Calls `i2c_handle_frame()`. +* Writes reply back over USB. + +## `tcp_transport.c` + +* Same framing. +* Calls same `i2c_handle_frame()`. +* Writes reply over TCP. + + +# Notes + +* The framing + transport layer is swappable. +* The I²C logic is isolated. + +# Result + +* USB for development/debug. +* TCP for deployment. +* Zero duplication of protocol logic. diff --git a/tcp-command-frame/CMakeLists.txt b/tcp-command-frame/CMakeLists.txt new file mode 100644 index 0000000..b9a7d83 --- /dev/null +++ b/tcp-command-frame/CMakeLists.txt @@ -0,0 +1,26 @@ +cmake_minimum_required(VERSION 3.13) + +set(PICO_BOARD pico_w) +include(pico_sdk_import.cmake) + +project(pico_w_tcp_command_framing C CXX ASM) +set(CMAKE_C_STANDARD 11) + +pico_sdk_init() + +add_executable(pico_w_tcp_command_framing + main.c +) + +target_include_directories(pico_w_tcp_command_framing PRIVATE + ${CMAKE_CURRENT_LIST_DIR} + ${CMAKE_CURRENT_LIST_DIR}/../secrets +) + +target_link_libraries(pico_w_tcp_command_framing + pico_stdlib + pico_cyw43_arch_lwip_poll + pico_lwip_nosys +) + +pico_add_extra_outputs(pico_w_tcp_command_framing) diff --git a/tcp-command-frame/client.mjs b/tcp-command-frame/client.mjs new file mode 100644 index 0000000..46d74da --- /dev/null +++ b/tcp-command-frame/client.mjs @@ -0,0 +1,58 @@ +// client.mjs +import net from 'node:net'; + +const HOST = '192.168.2.25'; // <-- set Pico IP +const PORT = 5505; + +function buildFrame(cmd, payload) { + const len = payload.length; + const frame = Buffer.alloc(3 + len); + + frame[0] = cmd; + frame[1] = len & 0xff; // len_lo + frame[2] = (len >> 8) & 0xff; // len_hi + payload.copy(frame, 3); + + return frame; +} + +function parseFrame(buffer) { + if (buffer.length < 3) { + return null; + } + + const cmd = buffer[0]; + const len = buffer[1] | (buffer[2] << 8); + + if (buffer.length < 3 + len) { + return null; + } + + const payload = buffer.subarray(3, 3 + len); + return { cmd, payload }; +} + +const socket = net.createConnection({ host: HOST, port: PORT }); + +let rxBuffer = Buffer.alloc(0); + +socket.on('connect', () => { + const payload = Buffer.from('Test'); + const frame = buildFrame(0x10, payload); + socket.write(frame); +}); + +socket.on('data', (chunk) => { + rxBuffer = Buffer.concat([rxBuffer, chunk]); + + const frame = parseFrame(rxBuffer); + if (frame) { + console.log('CMD:', frame.cmd); + console.log('Payload:', frame.payload.toString()); + socket.end(); + } +}); + +socket.on('error', (err) => { + console.error(err); +}); diff --git a/tcp-command-frame/lwipopts.h b/tcp-command-frame/lwipopts.h new file mode 100644 index 0000000..d30449f --- /dev/null +++ b/tcp-command-frame/lwipopts.h @@ -0,0 +1,37 @@ +#ifndef LWIPOPTS_H +#define LWIPOPTS_H + +/* Platform */ +#define NO_SYS 1 +#define LWIP_SOCKET 0 +#define LWIP_NETCONN 0 +#define LWIP_TIMEVAL_PRIVATE 0 + +/* Memory */ +#define MEM_ALIGNMENT 4 +#define MEM_SIZE (8 * 1024) +#define MEMP_NUM_PBUF 16 +#define MEMP_NUM_UDP_PCB 4 +#define MEMP_NUM_TCP_PCB 4 +#define MEMP_NUM_TCP_PCB_LISTEN 4 +#define MEMP_NUM_SYS_TIMEOUT 8 + +/* Pbufs */ +#define PBUF_POOL_SIZE 16 +#define PBUF_POOL_BUFSIZE 1520 + +/* IP */ +#define LWIP_IPV4 1 +#define LWIP_IPV6 0 +#define LWIP_ICMP 1 +#define LWIP_DHCP 1 +#define LWIP_UDP 1 +#define LWIP_TCP 1 + +/* Checksums */ +#define CHECKSUM_BY_HARDWARE 1 + +/* Debug */ +#define LWIP_DEBUG 0 + +#endif /* LWIPOPTS_H */ diff --git a/tcp-command-frame/main.c b/tcp-command-frame/main.c new file mode 100644 index 0000000..04c79d5 --- /dev/null +++ b/tcp-command-frame/main.c @@ -0,0 +1,185 @@ +#include +#include + +#include "pico/stdlib.h" +#include "pico/cyw43_arch.h" + +#include "lwip/netif.h" +#include "lwip/tcp.h" +#include "lwip/ip4_addr.h" + +#include "wifi-settings.h" + +#define MAX_PAYLOAD 256 +#define TCP_PORT 5505 + +extern struct netif *netif_default; + +enum { + READ_CMD, + READ_LEN0, + READ_LEN1, + READ_PAYLOAD +}; + +struct conn_state { + uint8_t state; + uint8_t cmd; + uint16_t len; + uint16_t received; + uint8_t buf[MAX_PAYLOAD]; +}; + +static void handle_frame(struct tcp_pcb *pcb, + uint8_t cmd, + uint8_t *payload, + uint16_t len) +{ + (void)cmd; + (void)payload; + (void)len; + + const char reply_payload[] = "Hello"; + const uint16_t reply_len = 5; + + uint8_t frame[3 + reply_len]; + + frame[0] = 0x01; // ACK command + frame[1] = (uint8_t)(reply_len & 0xFF); + frame[2] = (uint8_t)(reply_len >> 8); + memcpy(&frame[3], reply_payload, reply_len); + + tcp_write(pcb, frame, sizeof(frame), TCP_WRITE_FLAG_COPY); + tcp_output(pcb); +} + +static err_t on_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err) { + (void)err; + + struct conn_state *st = (struct conn_state *)arg; + + if (!p) { + free(st); + tcp_close(pcb); + return ERR_OK; + } + + struct pbuf *q = p; + + while (q) { + uint8_t *data = (uint8_t *)q->payload; + uint16_t i = 0; + + while (i < q->len) { + uint8_t b = data[i++]; + + if (st->state == READ_CMD) { + st->cmd = b; + st->len = 0; + st->received = 0; + st->state = READ_LEN0; + } + else if (st->state == READ_LEN0) { + st->len = (uint16_t)b; + st->state = READ_LEN1; + } + else if (st->state == READ_LEN1) { + st->len |= ((uint16_t)b << 8); + + if (st->len > MAX_PAYLOAD) { + pbuf_free(p); + free(st); + tcp_abort(pcb); + return ERR_ABRT; + } + + st->received = 0; + st->state = (st->len == 0) ? READ_CMD : READ_PAYLOAD; + + if (st->len == 0) { + handle_frame(pcb, st->cmd, st->buf, 0); + } + } + else { /* READ_PAYLOAD */ + st->buf[st->received++] = b; + + if (st->received == st->len) { + handle_frame(pcb, st->cmd, st->buf, st->len); + st->state = READ_CMD; + } + } + } + + q = q->next; + } + + tcp_recved(pcb, p->tot_len); + pbuf_free(p); + return ERR_OK; +} + +static err_t on_accept(void *arg, struct tcp_pcb *newpcb, err_t err) { + (void)arg; + (void)err; + + struct conn_state *st = (struct conn_state *)calloc(1, sizeof(struct conn_state)); + if (!st) { + tcp_abort(newpcb); + return ERR_ABRT; + } + + st->state = READ_CMD; + + tcp_arg(newpcb, st); + tcp_recv(newpcb, on_recv); + + return ERR_OK; +} + +int main() { + stdio_init_all(); + + if (cyw43_arch_init()) { + return -1; + } + + cyw43_arch_enable_sta_mode(); + + if (cyw43_arch_wifi_connect_timeout_ms( + WIFI_SSID, + WIFI_PASS, + CYW43_AUTH_WPA2_AES_PSK, + 30000)) { + return -1; + } + + struct tcp_pcb *listen_pcb = tcp_new_ip_type(IPADDR_TYPE_V4); + if (!listen_pcb) { + return -1; + } + + if (tcp_bind(listen_pcb, IP_ADDR_ANY, TCP_PORT) != ERR_OK) { + tcp_close(listen_pcb); + return -1; + } + + listen_pcb = tcp_listen(listen_pcb); + tcp_accept(listen_pcb, on_accept); + + bool dhcp_done = false; + + while (true) { + cyw43_arch_poll(); + + if (!dhcp_done) { + if (netif_default && + netif_is_up(netif_default) && + !ip4_addr_isany_val(*netif_ip4_addr(netif_default))) { + dhcp_done = true; + cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1); + } + } + + sleep_ms(1); + } +} diff --git a/tcp-command-frame/pico_sdk_import.cmake b/tcp-command-frame/pico_sdk_import.cmake new file mode 100644 index 0000000..d493cc2 --- /dev/null +++ b/tcp-command-frame/pico_sdk_import.cmake @@ -0,0 +1,121 @@ +# This is a copy of /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}) diff --git a/tcp-command-frame/readme.md b/tcp-command-frame/readme.md new file mode 100644 index 0000000..777b61d --- /dev/null +++ b/tcp-command-frame/readme.md @@ -0,0 +1,60 @@ +# TCP Command Frame + +## Authorship + +This document was generated using ChatGPT (OpenAI), version 5.2. +It has not been independently reviewed or validated yet. + +# Planned design + +## Transport + +* TCP (lwIP raw API). +* Single synchronous request/response per connection. +* TCP flow control is the only queue. + +## Future goals + +* HMAC with preshared key + +## Framing + + +``` +cmd (1 byte) +len (2 bytes, uint16) +payload (len bytes) +``` + +## Limits + +* `MAX_PAYLOAD` compile-time constant. +* Fixed local frame buffer: `uint8_t frame[MAX_PAYLOAD]`. +* No dynamic allocation based on `len`. + +## Parser + +* Stateful stream parser (READ_CMD → READ_LEN → READ_PAYLOAD). +* Accumulate until full frame received. +* When `len > MAX_PAYLOAD` → `tcp_abort()` immediately. +* On complete frame → execute command → send response → reset parser. + +## Memory safety + +* Only copy up to `MAX_PAYLOAD`. +* Call `tcp_recved()` only for consumed bytes. +* `pbuf_free()` after processing. +* No resynchronization logic. +* Protocol violation ⇒ connection closed. + +## Commands (initial) + +* `SETUP_I2C` +* `I2C_XFER` (write + read with bounded `wlen`/`rlen`) + +## Result + +* Deterministic RAM usage. +* Clear failure behavior. +* Minimal parser complexity. +* No reliance on TCP message boundaries.