feat(lua): add lua_driver_twai -- TWAI (CAN bus) Lua driver by ayyaris · Pull Request #96 · espressif/esp-claw

ayyaris · 2026-05-19T09:48:20Z

Summary

Adds lua_driver_twai, a new Lua module that exposes the ESP32 TWAI (Two-Wire Automotive Interface / CAN bus) peripheral to Lua scripts via the ESP-IDF v6 esp_driver_twai node API.

API

local twai = require("twai")

local can = twai.new(tx_gpio, rx_gpio, bitrate [, opts])
-- opts: { listen_only=bool, loopback=bool }

can:enable()
can:disable()
can:send(id, data [, is_extended [, is_rtr]])
local frame = can:receive([timeout_ms])   -- {id, data, extended, rtr} | nil
local st    = can:status()               -- {state, tx_errors, rx_errors, ...}
can:recover()
can:close()

Implementation

ISR-driven RX queue (depth 32) via on_rx_done callback — zero-copy path from ISR to FreeRTOS queue
Kconfig: APP_CLAW_LUA_DRIVER_TWAI (default y when SOC_TWAI_SUPPORTED)
Registration: components/common/app_claw/idf_component.yml conditional dependency + app_lua_modules.c registration
Requires esp_driver_twai (IDF v6+)

Files

File	Purpose
`components/lua_modules/lua_driver_twai/src/lua_driver_twai.c`	Module implementation
`components/lua_modules/lua_driver_twai/src/lua_driver_twai.h`	Public header
`components/lua_modules/lua_driver_twai/CMakeLists.txt`	Component registration
`components/lua_modules/lua_driver_twai/README.md`	Usage docs + examples
`components/common/app_claw/Kconfig`	`APP_CLAW_LUA_DRIVER_TWAI` option
`components/common/app_claw/app_lua_modules.c`	Module registration
`components/common/app_claw/idf_component.yml`	Conditional dependency

Test plan

Builds without error on ESP32-S3 (SOC_TWAI_SUPPORTED=y)
Builds without error on ESP32-C3 / other TWAI-capable chips
require("twai") succeeds in Lua runtime
twai.new() creates node, enable()/send()/receive() work on bus

🤖 Generated with Claude Code

Wraps the ESP-IDF v6 esp_driver_twai node API as a Lua module: API (require("twai")): twai.new(tx_gpio, rx_gpio, bitrate [, opts]) -> node node:enable() node:disable() node:send(id, data [, is_extended [, is_rtr]]) node:receive([timeout_ms]) -> {id, data, extended, rtr} | nil node:status() -> {state, tx_errors, rx_errors, ...} node:recover() node:close() Implementation: - ISR-driven RX queue (depth 32) via on_rx_done callback - Registered via Kconfig APP_CLAW_LUA_DRIVER_TWAI (default y when SOC_TWAI_SUPPORTED) - idf_component.yml: conditional dependency on lua_driver_twai Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CLAassistant · 2026-05-19T09:48:47Z

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

Alessio Ayyari seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
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Copilot

Pull request overview

This PR introduces a new twai Lua module (lua_driver_twai) to expose the ESP32 TWAI (CAN bus) peripheral via ESP-IDF v6’s esp_driver_twai node API, wiring it into app_claw’s Kconfig/dependency system and Lua module registration.

Changes:

Adds a new lua_driver_twai component implementing twai.new()/enable()/send()/receive()/status()/recover()/close() with an ISR-driven RX queue.
Adds APP_CLAW_LUA_DRIVER_TWAI Kconfig and idf_component.yml conditional dependency, plus registration in app_lua_modules.c.
Removes LVGL Lua module configuration/dependency/registration from app_claw (appears unrelated and breaking).

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
components/lua_modules/lua_driver_twai/src/lua_driver_twai.c	Implements the TWAI Lua driver, including ISR RX callback + Lua API surface.
components/lua_modules/lua_driver_twai/src/lua_driver_twai.h	Public header for module open/registration.
components/lua_modules/lua_driver_twai/README.md	Documents usage and examples for the `twai` Lua module.
components/lua_modules/lua_driver_twai/CMakeLists.txt	Registers the new component and its dependencies.
components/common/app_claw/Kconfig	Adds `APP_CLAW_LUA_DRIVER_TWAI` option; also removes LVGL option.
components/common/app_claw/idf_component.yml	Adds conditional dependency for `lua_driver_twai`; also removes LVGL dependency block.
components/common/app_claw/app_lua_modules.c	Registers the `twai` module; also removes LVGL include/registration entries.

Comments suppressed due to low confidence (1)

components/common/app_claw/idf_component.yml:272

The conditional dependency block for lua_module_lvgl was removed from app_claw’s idf_component.yml, which will prevent the existing lua_module_lvgl component from being pulled in when enabled. If LVGL support is still intended to be available, please re-add the lua_module_lvgl dependency rules/path entry (and keep it aligned with the corresponding Kconfig option).

  lua_module_led_strip:
    rules:
      - if: $CONFIG{APP_CLAW_CAP_LUA} == True
      - if: $CONFIG{APP_CLAW_LUA_MODULE_LED_STRIP} == True
    path: ../../lua_modules/lua_module_led_strip

  lua_module_magnetometer:
    rules:
      - if: $CONFIG{APP_CLAW_CAP_LUA} == True
      - if: $CONFIG{APP_CLAW_LUA_MODULE_MAGNETOMETER} == True
    path: ../../lua_modules/lua_module_magnetometer

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

        config APP_CLAW_LUA_MODULE_LED_STRIP
            bool "Enable LED strip Lua module"
            default y
            help
                Enable the LED strip Lua module and keep app_claw's direct dependency
                on lua_module_led_strip when Lua capability is enabled.

-        config APP_CLAW_LUA_MODULE_LVGL
-            bool "Enable LVGL Lua module"
-            default n
-            help
-                Enable the LVGL Lua module and keep app_claw's direct dependency
-                on lua_module_lvgl when Lua capability is enabled.
-
        config APP_CLAW_LUA_MODULE_MAGNETOMETER
            bool "Enable magnetometer Lua module"
            default n


 #if CONFIG_APP_CLAW_LUA_MODULE_LCD_TOUCH && defined(CONFIG_ESP_BOARD_DEV_LCD_TOUCH_SUPPORT) && defined(CONFIG_ESP_BOARD_DEV_LCD_TOUCH_SUB_I2C_SUPPORT)
 #include "lua_module_lcd_touch.h"
 #endif
 #if CONFIG_APP_CLAW_LUA_MODULE_LED_STRIP
 #include "lua_module_led_strip.h"
 #endif
-#if CONFIG_APP_CLAW_LUA_MODULE_LVGL
-#include "lua_module_lvgl.h"
-#endif
 #if CONFIG_APP_CLAW_LUA_MODULE_MAGNETOMETER
 #include "lua_module_magnetometer.h"
 #endif


+    int tx_gpio  = (int)luaL_checkinteger(L, 1);
+    int rx_gpio  = (int)luaL_checkinteger(L, 2);
+    uint32_t bps = (uint32_t)luaL_checkinteger(L, 3);
+
+    bool listen_only = false;
+    bool loopback    = false;
+    if (lua_istable(L, 4)) {
+        lua_getfield(L, 4, "listen_only");
+        listen_only = lua_toboolean(L, -1);
+        lua_pop(L, 1);
+        lua_getfield(L, 4, "loopback");
+        loopback = lua_toboolean(L, -1);
+        lua_pop(L, 1);
+    }


+    memcpy(item.data, buf, item.len);
+
+    BaseType_t woken = pdFALSE;
+    xQueueSendFromISR(ud->rx_queue, &item, &woken);
+    return woken == pdTRUE;


+    twai_rx_item_t item = {
+        .id          = frame.header.id,
+        .is_extended = frame.header.ide,
+        .is_rtr      = frame.header.rtr,
+        .len         = (uint8_t)(frame.header.dlc > LUA_DRIVER_TWAI_DATA_MAX
+                                 ? LUA_DRIVER_TWAI_DATA_MAX : frame.header.dlc),
+    };
+    memcpy(item.data, buf, item.len);
+


+
+    esp_err_t err = twai_node_transmit(ud->node, &frame, pdMS_TO_TICKS(100));
+    if (err != ESP_OK) {
+        return luaL_error(L, "twai: transmit failed (%d)", err);


+    twai_node_record_t record = {0};
+    esp_err_t err = twai_node_get_info(ud->node, &status, &record);
+    if (err != ESP_OK) {
+        return luaL_error(L, "twai: get_info failed (%d)", err);


+    lua_driver_twai_ud_t *ud = twai_check_ud(L, 1);
+    esp_err_t err = twai_node_recover(ud->node);
+    if (err != ESP_OK) {
+        return luaL_error(L, "twai: recover failed (%d)", err);


+        },
+        .buffer     = buf,
+        .buffer_len = data_len,
+    };
+
+    esp_err_t err = twai_node_transmit(ud->node, &frame, pdMS_TO_TICKS(100));
+    if (err != ESP_OK) {


+static int twai_new(lua_State *L)
+{
+    int tx_gpio  = (int)luaL_checkinteger(L, 1);
+    int rx_gpio  = (int)luaL_checkinteger(L, 2);
+    uint32_t bps = (uint32_t)luaL_checkinteger(L, 3);
+
+    bool listen_only = false;


ayyaris mentioned this pull request May 19, 2026

feat(idf-v6, board, lua): IDF v6.0.1 compat + WT32-SC01 Plus board + CAN bus Lua driver #86

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laride requested a review from Copilot May 19, 2026 12:28

Copilot started reviewing on behalf of laride May 19, 2026 12:30 View session

Copilot AI reviewed May 19, 2026

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feat(lua): add lua_driver_twai -- TWAI (CAN bus) Lua driver#96

feat(lua): add lua_driver_twai -- TWAI (CAN bus) Lua driver#96
ayyaris wants to merge 1 commit into
espressif:masterfrom
ayyaris:feat/lua-driver-twai

ayyaris commented May 19, 2026

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ayyaris commented May 19, 2026

Summary

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Implementation

Files

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