mattandClaude Opus 5
d2e4c974dd
ESP-IDF v5.3.2 firmware for the CrowPanel 2.1" rotary display. Builds clean;
nothing has been run on hardware yet.
Hardware verified against Elecrow's own source for this board and
cross-checked against their ESPHome config, per PRD 8.1. Three corrections to
the PRD's pinout, all documented in docs/HARDWARE.md:
- touch is CST826 at 0x15, not CST816 (chip ID reads 0x11, not 0xB4)
- the ST7701S needs a 3-wire SPI bus on GPIO 16/2/1 that the PRD omitted;
without it the init sequence cannot be sent and the panel stays black
- the backlight is GPIO6
Two further departures from the PRD, both forced by facts on the ground:
- Transport is MQTT, not HTTP. zigbee2mqtt has no REST endpoint for live
sensor state. Subscribing to the broker also gets retained topics, so
every room's last reading arrives on connect rather than after a poll.
- The furnace is 2-wire R/W with no C, not 3-wire. The board needs its own
5V supply. The thermostat's 5 CPH setting is enforced as a minimum
12-minute period between heat-call starts, which a minimum off-time alone
does not achieve.
All of PRD section 5 is implemented in the relay layer itself: fail-open,
watchdog-gated output, max on-time, min off-time, cycle-rate limit, startup
lockout, and the stale-data fallback ladder down to open-loop freeze
protection. The one gap that cannot be closed in software — the PCF8574 not
resetting when the ESP32 does — is documented rather than papered over.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
#include "i2c_bus.h"
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#include "esp_log.h"
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static const char *TAG = "i2c";
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static i2c_master_bus_handle_t s_bus;
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esp_err_t i2c_bus_init(void)
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{
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if (s_bus) {
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return ESP_OK;
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}
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i2c_master_bus_config_t cfg = {
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.i2c_port = I2C_NUM_0,
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.sda_io_num = I2C_BUS_SDA_GPIO,
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.scl_io_num = I2C_BUS_SCL_GPIO,
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.clk_source = I2C_CLK_SRC_DEFAULT,
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.glitch_ignore_cnt = 7,
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.flags.enable_internal_pullup = true,
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};
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esp_err_t err = i2c_new_master_bus(&cfg, &s_bus);
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if (err != ESP_OK) {
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ESP_LOGE(TAG, "bus init failed: %s", esp_err_to_name(err));
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return err;
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}
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ESP_LOGI(TAG, "bus up on SDA=%d SCL=%d @ %d Hz",
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I2C_BUS_SDA_GPIO, I2C_BUS_SCL_GPIO, I2C_BUS_FREQ_HZ);
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return ESP_OK;
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}
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esp_err_t i2c_bus_add_device(uint8_t addr, i2c_master_dev_handle_t *out)
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{
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if (!s_bus) {
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return ESP_ERR_INVALID_STATE;
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}
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i2c_device_config_t cfg = {
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.dev_addr_length = I2C_ADDR_BIT_LEN_7,
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.device_address = addr,
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.scl_speed_hz = I2C_BUS_FREQ_HZ,
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};
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return i2c_master_bus_add_device(s_bus, &cfg, out);
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}
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int i2c_bus_scan(void)
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{
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if (!s_bus) {
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ESP_LOGE(TAG, "scan before init");
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return -1;
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}
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int found = 0;
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ESP_LOGI(TAG, "scanning...");
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for (uint8_t addr = 0x08; addr < 0x78; addr++) {
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if (i2c_master_probe(s_bus, addr, 50) == ESP_OK) {
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const char *who = "?";
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if (addr == 0x21) {
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who = "PCF8574 expander";
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} else if (addr == 0x15) {
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who = "CST826 touch";
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}
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ESP_LOGI(TAG, " 0x%02X %s", addr, who);
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found++;
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}
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}
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if (found == 0) {
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/* Loud, because this means the board or the pinout is wrong, and no
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* amount of display debugging past this point is worth doing. */
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ESP_LOGE(TAG, "no I2C devices found — check SDA=%d / SCL=%d wiring "
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"before debugging anything else",
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I2C_BUS_SDA_GPIO, I2C_BUS_SCL_GPIO);
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} else {
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ESP_LOGI(TAG, "scan done, %d device(s)", found);
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}
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return found;
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}
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