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# Prototype Driver for STM Wi-Fi Expansion Boards based on the SPWFxx Module for STM32 Nucleo #

## Currently supported expansion boards
 * [X-NUCLEO-IDW01M1](http://www.st.com/content/st_com/en/products/ecosystems/stm32-open-development-environment/stm32-nucleo-expansion-boards/stm32-ode-connect-hw/x-nucleo-idw01m1.html), by setting `mbed` configuration variable `idw0xx1.expansion-board` to value `IDW01M1`
 * [X-NUCLEO-IDW04A1](http://www.st.com/content/st_com/en/products/ecosystems/stm32-open-development-environment/stm32-nucleo-expansion-boards/stm32-ode-connect-hw/x-nucleo-idw04a1.html), by setting `mbed` configuration variable `idw0xx1.expansion-board` to value `IDW04A1`. You might also need to define macro `IDW04A1_WIFI_HW_BUG_WA` _(see beyond)_.

## Configuration examples

### Generic concepts

For the ones, which might be less familiar with the **"The mbed configuration system"** in general, here is a [link](https://docs.mbed.com/docs/mbed-os-handbook/en/latest/advanced/config_system/) which points to the latest version of the respective _mbed OS 5 handbook tutorial_.

Furthermore, with respect to this driver, pls. refer to files [`mbed_app_idw01m1.json`](https://github.com/ARMmbed/wifi-x-nucleo-idw01m1/blob/master/mbed_app_idw01m1.json) and [`mbed_app_idw04a1.json`](https://github.com/ARMmbed/wifi-x-nucleo-idw01m1/blob/master/mbed_app_idw04a1.json) regarding additional reference for what is explained beyond.

### IDW01M1

Add the following lines to the `target_overrides`-section of your `mbed_app.json` file.

``` json
            "idw0xx1.expansion-board": "IDW01M1",
            "drivers.uart-serial-txbuf-size": 512,
            "drivers.uart-serial-rxbuf-size": 512
```

`IDW01M1` is the default value in the [`mbed_lib.json`](https://github.com/ARMmbed/wifi-x-nucleo-idw01m1/blob/master/mbed_lib.json) file, so setting the expansion board is not mandatory for `IDW01M1`, while setting the TX & RX buffer sizes is highly recommended.

### IDW04A1

Add the following lines to the `target_overrides`-section of your `mbed_app.json` file.

``` json
            "idw0xx1.expansion-board": "IDW04A1",
            "drivers.uart-serial-txbuf-size": 512,
            "drivers.uart-serial-rxbuf-size": 512
```

### Further configuration macros

All configuration options mentioned in this section are optional and when required have to be added to the `macros`-section of your `mbed_app.json` file, e.g.:

``` json
    "macros": [..., "IDW04A1_WIFI_HW_BUG_WA", "SPWFSAXX_RESET_PIN=D7"]
```

Beyond you can find the list of available configuration macros each with a short explanation:
 * `IDW04A1_WIFI_HW_BUG_WA`: activates the HW bug workaround for `IDW04A1`
 * `SPWFSAXX_WAKEUP_PIN`:    defines module wakeup pin _(requires value)_ 
 * `SPWFSAXX_RESET_PIN`:     defines module reset pin _(requires value)_ 
 * `SPWFSAXX_RTS_PIN`:       defines RTS pin of the UART device used _(requires value)_ 
 * `SPWFSAXX_CTS_PIN`:       defines CTS pin of the UART device used _(requires value)_ 

**Note**: if the values of both `SPWFSAXX_RTS_PIN` and `SPWFSAXX_CTS_PIN` are different from `NC`, hardware flow control - if available on your development board - will be enabled on the used UART device (provided you are using `mbed-os` version greater than or equal to `v5.7.0`).


## Firmware upgrade

Please make sure that you are using the latest firmware available for the expansion boards. For information on how to perform a FW upgrade you may refer to [X-CUBE-WIFI1](http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software-expansion/x-cube-wifi1.html), especially to document **"X-NUCLEO-IDW0xx1- FW upgrading over UART_v1.2.pdf"** which is contained within folder **"Documentation"** of the X-CUBE-WIFI1 software archive you need to download. 

The actual firmware `.bin` or `.hex` files can be found under 
- [STSW-WIFI001](http://www.st.com/content/st_com/en/products/embedded-software/wireless-connectivity-software/stsw-wifi001.html) _for what concerns expansion board_ X-NUCLEO-IDW01M1 _and under_
- [STSW-WIFI004](http://www.st.com/content/st_com/en/products/embedded-software/wireless-connectivity-software/stsw-wifi004.html) _when considering_ X-NUCLEO-IDW04A1.


## Known limitations

 * Like explained in issue [#11](https://github.com/ARMmbed/wifi-x-nucleo-idw01m1/issues/11), sockets might fail to close in case they are connected to a streaming server (e.g. a [RFC 864](https://tools.ietf.org/html/rfc864) test server).
 * As highlighted by issue [#13](https://github.com/ARMmbed/wifi-x-nucleo-idw01m1/issues/13), the module FW limits the maximum segment size for TCP to 730 bytes, while the maximum UDP datagram length might even be further limited (but usually is also equal to 730 bytes).