# FreeRTOS on XMOS
###### tags: `xcore` `xmos`

[SMP Demo for the XMOS XCORE.AI Explorer Board](https://freertos.org/smp-demo-for-xmos-xcore-ai-explorer-board.html)

https://github.com/FreeRTOS/FreeRTOS-SMP-Demos

* The project files for this demo
`FreeRTOS/Demo/XCORE.AI_xClang/RTOSDemo directory`

* FreeRTOS Port files compiled in the project
`FreeRTOS/Source/portable/ThirdParty/xClang/XCORE.AI`

* Common I/O interfaces
GPIO
UART
I2C
I2S
PDM microphones
QSPI flash
SPI
USB
Clock control

* xcore features
Intertile channel communication
Software defined memory (xcore.ai only)
Software defined L2 Cache (xcore.ai only)

* External parts
Silicon Labs WF200 series WiFi transceiver

* Software Services
DHCP server
Dispatcher
FAT filesystem
HTTP parser
JSON parser
MQTT client
SNTP client
TLS
USB stack
WiFi connection manager

---

These drivers are all found in the SDK under the path **modules/rtos/modules/drivers (fwk_rtos/modules/drivers)**.

Abstraction layer is found under the path **modules/rtos/modules/osal (fwk_rtos/modules/osal)**.

These services are all found in the SDK under the path **modules/rtos/modules/sw_services (fwk_rtos/modules/sw_services)**.

A fully functional example application that can be found in the SDK under the path **examples/freertos/explorer_board (xcore_sdk/examples/freertos/explorer_board)**.

Additional code to initialize the SoC platform for this example is provided by a board support configuration library **modules/rtos/modules/board_support/XCORE-AI-EXPLORER_2V0/platform (fwk_rtos/modules/bsp_config/XCORE-AI-EXPLORER_2V0/platform)**.

The bsp_configs provided with the XCORE SDK in **modules/rtos/modules/bsp_config (fwk_rtos/modules/bsp_config)** are an excellent starting point.

* Set XTC environment
* Looking files
* /FreeRTOS/Demo/XCORE.AI_xClang/RTOSDemo/src/FreeRTOSConfig.h

    #define configNUM_CORES
    ...
    #define configRUN_MULTIPLE_PRIORITIES 
    #define configUSE_CORE_AFFINITY   

* /FreeRTOS-SMP-Demos/FreeRTOS/Demo/XCORE.AI_xClang/RTOSDemo/src/testing_main.h

    #define mainCREATE_SIMPLE_BLINKY_DEMO_ONLY  1

* /FreeRTOS-SMP-Demos/FreeRTOS/Demo/XCORE.AI_xClang/RTOSDemo/src/XCORE-AI-EXPLORER.xn

    <Packages>
    <Package id="0" Type="XS3-UnA-1024-QF60A">
      <Nodes>
        <Node Id="0" InPackageId="0" Type="XS3-L16A-1024" Oscillator="24MHz" SystemFrequency="600MHz" ReferenceFrequency="100MHz">
          <Boot>
            <Source Location="bootFlash"/>
          </Boot>
          <Extmem sizeMbit="1024" Frequency="300MHz">
            <Padctrl clk="0x30" cke="0x30" cs_n="0x30" we_n="0x30" cas_n="0x30" ras_n="0x30" addr="0x30" ba="0x30" dq="0x31" dqs="0x31" dm="0x30"/>
          </Extmem>
          <Tile Number="0" Reference="tile[0]">
            <Port Location="XS1_PORT_1B" Name="PORT_SQI_CS"/>
            <Port Location="XS1_PORT_1C" Name="PORT_SQI_SCLK"/>
            <Port Location="XS1_PORT_4B" Name="PORT_SQI_SIO"/>

            <!-- SPI ports -->
            <Port Location="XS1_PORT_1A"  Name="PORT_SSB"/>
            <Port Location="XS1_PORT_1C"  Name="PORT_SQI_SCLK_0"/>
            <Port Location="XS1_PORT_1D"  Name="PORT_SPI_MOSI"/>
            <Port Location="XS1_PORT_1P"  Name="PORT_SPI_MISO"/>

            <!-- I2C ports -->
            <Port Location="XS1_PORT_1N"  Name="PORT_I2C_SCL"/>
            <Port Location="XS1_PORT_1O"  Name="PORT_I2C_SDA"/>
            
            <!-- LED -->
            <Port Location="XS1_PORT_4F" Name="PORT_LEDS"/>

          </Tile>
          <Tile Number="1" Reference="tile[1]">
            <!-- Mic related ports -->
            <Port Location="XS1_PORT_1G" Name="PORT_PDM_CLK"/>
            <Port Location="XS1_PORT_1F" Name="PORT_PDM_DATA"/>

            <!-- Audio ports -->
            <Port Location="XS1_PORT_1D"  Name="PORT_MCLK_IN_OUT"/>
            <Port Location="XS1_PORT_1C"  Name="PORT_I2S_BCLK"/>
            <Port Location="XS1_PORT_1B"  Name="PORT_I2S_LRCLK"/>
            <Port Location="XS1_PORT_1A"  Name="I2S_MIC_DATA"/>
            <Port Location="XS1_PORT_1K"  Name="I2S_DATA_IN"/>

          </Tile>
        </Node>
      </Nodes>
    </Package>
  </Packages>

* /FreeRTOS-SMP-Demos/FreeRTOS/Demo/XCORE.AI_xClang/RTOSDemo/src/partest/partest.c

    static int led_seq = 0;

    typedef enum {
        LED_BLACK = 0xFF,
        LED_RED = 0xFD,
        LED_GREEN = 0xFB,
        LED_BLUE = 0xF7,
        LED_YELLOW = 0xF9,
        LED_PURPLE = 0xF5,
        LED_AQUA = 0xF3,
        LED_WHITE = 0xF1,
    };

    uint8_t led_color[] = {
        LED_BLACK, LED_RED, LED_GREEN, LED_BLUE,
        LED_YELLOW, LED_PURPLE, LED_AQUA, LED_WHITE
    };
    ...
    DEFINE_RTOS_INTERRUPT_CALLBACK( pxLEDUpdateISR, pvData )
    {
        led_bitmap = led_color[led_seq] & 0xFFFF;
	    if(xCmd.led==1)
		led_seq = (led_seq+1)%8;
    }