system/get_cp_fw_version/mcu_host

# get_cp_fw_version — Host

Smallest end-to-end ESP-Hosted scenario: bring up the host stack, open
a transport to the coprocessor, fetch the CP firmware version via
`eh_host_sys_get_cp_fw_version` (RPC `system` feature), print
`major.minor.patch` + revision / prerelease / build, exit. Used as
the bring-up smoke test for new ports — exercises every layer that
moves a single RPC round-trip, with no Wi-Fi / BT / OTA moving parts.

## Supported Platforms and Transports

### Supported Coprocessors

| Coprocessor | ESP32 | ESP32-C Series | ESP32-S Series |
| :----------: | :---: | :------------: | :------------: |
| Support     | Yes   | Yes            | Yes            |

### Supported Host Devices

| Host Device | ESP32-P4 | ESP32-H2 | Other MCUs | Linux |
| :---------: | :------: | :------: | :--------: | :---: |
| Support     | Yes | Yes | [Yes](https://github.com/espressif/esp-hosted/blob/master/docs/getting-started-mcu.md) | [Yes](https://github.com/espressif/esp-hosted/blob/master/docs/getting-started-linux.md) |

### Supported Connection buses

| Connection bus | SDIO | SPI Full-Duplex | SPI Half-Duplex | UART |
| :------------- | :--: | :-------------: | :-------------: | :--: |
| Linux host     | Yes  | Yes             | No              | No   |
| MCU host       | Yes  | Yes             | Yes             | Yes  |

## Scenario

The simplest control-path round trip — a single RPC request and its response. It is the transport-health gate: if this works, the link is up.

```mermaid
sequenceDiagram
    participant App as Host app
    participant CP as Co-processor
    App->>CP: esp_hosted_get_coprocessor_fwversion() (RPC request)
    CP-->>App: version (major.minor.patch)
```

Select the transport (must match the co-processor):

```bash
cd examples/system/get_cp_fw_version/mcu_host
idf.py set-target esp32p4
idf.py menuconfig
```

```text
Component config
└── ESP-Hosted
     └── Configure host
          └── Host transport
               ├── Communication bus (co-processor <== bus ==> host)
               │    ├── ( ) SPI Full Duplex
               │    ├── (X) SDIO                    <── default (match the co-processor)
               │    ├── ( ) SPI Half Duplex
               │    └── ( ) UART
               └── SDIO Configuration               ← slot, bus width, GPIOs (defaults OK)
```

```text
Example Configuration
└── [ ] Use legacy esp_hosted_* compat-surface main    <── default off
```

Host dependency config is **pre-set in `sdkconfig.defaults`** (do not remove):

```text
CONFIG_ESP_HOSTED_HOST_FEAT_RPC=y          # RPC control path
CONFIG_ESP_HOSTED_HOST_FEAT_RPC_EXT_V2=y   # RPC ext-v2 (required)
CONFIG_ESP_HOSTED_HOST_FEAT_SYSTEM=y       # system feature — serves the CP fw-version query
```

Then flash and monitor:

```bash
idf.py -p <host_usb_serial_port> flash monitor
```

<!-- generated from ../README.md — edit that file, not this one -->