jpmschweitzerandClaude Fable 5
cb5826e02b
Root cause (verified against our exact IDF tree, not the community guess): the "258" in "sdio_write_task: Failed to send data: 258" is NOT a timeout (that is 263). 258 = 0x102 = ESP_ERR_INVALID_ARG. On the ESP32-P4, block- mode CMD53 writes require the SOURCE buffer to be 64-byte (cache-line) aligned; the IDF sdmmc driver rejects a misaligned source with INVALID_ARG BEFORE any bus activity. esp_hosts write loop then declares "Unrecoverable host sdio state" and reboots the whole P4. The audio TX payload is not 64-aligned, so streaming mic audio wedged on the very FIRST frame (which is exactly what we saw: listening -> instant Failed to send -> reboot). This also explains why buffer/queue/clock/retry tuning all did nothing: the write never reached the bus. And why our symptom was instant, not after ~100 writes (the community block-mode-desync theory) — it is the first misaligned buffer, every time. Fix: vendored esp_hosted 2.12.11 as an editable local component (overrides the registry copy) and bounce a misaligned TX payload through one aligned DMA scratch buffer in hosted_sdio_write_block (port_esp_hosted_host_sdio.c). TX is serialized by the bus lock so a single static bounce buffer is safe; freed in hosted_sdio_deinit. Host-only change — no C6 reflash. VERIFIED ON HARDWARE (autonomous self-test): 40s of continuous mic-audio upstream streaming — the traffic that previously wedged on the first frame — ran clean, zero timeouts, zero reboots. A guarded SDIO_TX_SELFTEST harness is kept (compiled out) for future SDIO stress testing. Credit: root cause + patch designed via multi-agent investigation; the precise 258=INVALID_ARG decode (correcting the upstream community timeout assumption) came from checking our actual esp_err.h. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
53 lines
2.2 KiB
Markdown
53 lines
2.2 KiB
Markdown
# GPIO Expander
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The ESP-Hosted solution provides a feature to control the GPIOs of the slave (co-processor) from the host MCU. This acts as a virtual GPIO expander over the existing transport link (SPI, SDIO, or UART), saving hardware pins and complexity on the host board.
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## Use Cases
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* Driving LEDs or status indicators on the slave board.
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* Reading button presses or sensor states connected to the slave.
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* Resetting or enabling/disabling peripherals connected to the slave.
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* Any application where the host needs simple digital I/O control over the slave.
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## API
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The GPIO control functionality is exposed through the `esp_hosted_cp_gpio.h` header file. The API is designed to be similar to the standard ESP-IDF GPIO driver.
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Key functions include:
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* `esp_hosted_cp_gpio_config()`: Configure a GPIO's mode (input/output), pull-up/pull-down, and interrupt type.
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* `esp_hosted_cp_gpio_set_level()`: Set the logic level of an output GPIO.
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* `esp_hosted_cp_gpio_get_level()`: Read the logic level of an input GPIO.
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* `esp_hosted_cp_gpio_set_direction()`: Change the direction (input/output) of a GPIO.
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* ... and more.
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## Enabling the Feature
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To use this feature, it must be enabled on both the host and the slave firmware.
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### Host Configuration
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In the host's `menuconfig`, enable the following option:
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```
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Component config --->
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ESP-Hosted --->
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[*] Enable GPIO Expander feature on host
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```
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This corresponds to the `CONFIG_ESP_HOSTED_ENABLE_GPIO_EXPANDER=y` option.
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### Slave Configuration
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In the slave's `menuconfig`, enable the following option:
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```
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(Top) → Example Configuration
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[*] Enable GPIO Expander support (host can control slave GPIOs)
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```
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This corresponds to the `CONFIG_ESP_HOSTED_ENABLE_GPIO_EXPANDER=y` option.
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## Safety Guard
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The slave firmware includes a safety mechanism to prevent the host from accidentally or maliciously interfering with GPIOs that are critical for the ESP-Hosted transport link itself. Any RPC request from the host to control a pin used by the active SPI, SDIO, or UART interface will be rejected by the slave.
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## Example
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An example demonstrating the usage of this feature can be found in the `examples/host_gpio_expander` directory.
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