Hello World on the M4¶

Objectives¶

• Build a hello world program for the mcu
• Load the program over JTAG, step through the program, see the output
• Load the program using the remoteproc system
• Load the program at boot time

Reference Documentation¶

• https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_06_00_18/exports/docs/api_guide_am62x/index.html
• https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_06_00_18/exports/docs/api_guide_am62x/GETTING_STARTED.html
• https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_06_00_18/exports/docs/api_guide_am62x/EXAMPLES_HELLO_WORLD.html

Prerequisites¶

• Install CCS and SDK
  • See M4FMCU_Development
• Fix target configuration paths in CCS 12.2
  • See CCS_am62x_target_configuration_fix
• Setup a name (target_62x) for your target
  • See Ssh_target_naming_and_port_forwarding
  • If you don't set up a name, replace the target_62x in the comands below with your target ip address
• Monitor the M4 uart
  • Use your favorite terminal connection program
    • Code Composer Terminal View
    • tera-term
    • putty

Steps - building the hello world program¶

• Start Code Composer with a new workspace
• Import a CCS Project from ~/ti/mcu_plus_sdk_am62x_08_06_00_18/examples/hello_world
  • pick am62x-sk/m4fss0-0_freertos
• Correct the JTAG emulator type if needed. Default is XDS110
  • Open the targetConfigs/AM62.ccxml target configuration
    • Use the drop-down list for Connection to pick the correct debug probe type
    • Click on the Save Configuration button to save the modification
  • If you get an error on the target configuration, make sure you followed the steps listed above about fixing the target configuration paths.
• Build program for debug

Steps - Load the program over JTAG, step through the program, see the output¶

• Launch Am62x Target configuration
  • Open Target Configurations View
  • Expand the Projects, expand hello_world..., expand targetConfigs
  • Select AM62.ccxml, right-mouse->Launch Selected Configuration
• Connect to target.
  • Select BLAZER_Cortex_M4F_1, right-mouse->Connect Target
• Reset CPU.
  • Menu Bar->Run->Reset->CPU Reset
• Load program.
  • Menu Bar->Run->Load->Load Program.
  • Browse Project. Pick debug executable (hello_world_....arm_clang.out)
    • The am62-mcu-m4f0_0-fw is a stripped version of the .out file so it is not suitable for debugging.
    • Press OK
  • Press OK
• Put breakpoint after call to DebugP_log() in hello_world.c
• Continue
• See output in console in Code Composer
  • Output will also appear on the M4 uart

Steps - Load the program using the remoteproc system¶

• Apply patches to the imported project
  • Without the patches, the program can be loaded via JTAG but not through the remoteproc process.
  • With the patches, the program can be loaded through the remoteproc process, but not through JTAG.
  • See m4_hello_world_patches_for_use_with_remoteproc
• Build release version
• Copy release version to /lib/firmware/hello_world/am62-mcu-m4f0_0-fw
  

  ssh target_62x mkdir -p /lib/firmware/hello_world
  scp Release/am62-mcu-m4f0_0-fw target_62x:/lib/firmware/hello_world
  

• link /lib/firmware/am62-mcu-m4f0_0-fw to hello_world
  

  ssh target_62x ln -sf /lib/firmware/hello_world/am62-mcu-m4f0_0-fw /lib/firmware/am62-mcu-m4f0_0-fw
  

• On the target
  • See the different remote processors
    

    cd /sys/class/remoteproc
    
    root@mitysom-am62x:/sys/class/remoteproc# tail */name
    ==> remoteproc0/name <==
    5000000.m4fss
    
    ==> remoteproc1/name <==
    78000000.r5f
    
    ==> remoteproc2/name <==
    30074000.pru
    
    ==> remoteproc3/name <==
    30078000.pru
    

  • Pick out the one for the mcu. e.g. remoteproc0
  • See the current state of the processor.
    

    tail *0/state
    running
    

  • Stop the processor
    

    echo 'stop' > *0/state
    [73439.834056] remoteproc remoteproc0: stopped remote processor 5000000.m4fss
    

  • Start the processor (will load the new program)
    

    echo 'start' > *0/state
    [73473.037249] remoteproc remoteproc0: powering up 5000000.m4fss
    [73473.044197] remoteproc remoteproc0: Booting fw image am62-mcu-m4f0_0-fw, size 79552
    [73473.052693]  remoteproc0#vdev0buffer: assigned reserved memory node m4f-dma-memory@9cb00000
    [73473.061740] virtio_rpmsg_bus virtio0: rpmsg host is online
    [73473.068466]  remoteproc0#vdev0buffer: registered virtio0 (type 7)
    [73473.074680] remoteproc remoteproc0: remote processor 5000000.m4fss is now up
    

  • Should see Hello World on the mcu uart.

Steps - Load the program at boot time¶

• Change program to repeatedly print hello world.
  • In hello_world.c change
    

        DebugP_log("Hello World!\r\n");
    

    
    to
    

        for (int ii = 0; ii < 1000; ++ii)
        {
            DebugP_log("%3d: Hello World!\r\n", ii);
            ClockP_sleep(5);
        }
    

  • Build release version
  • Copy Release/am62-mcu-m4f0_0-fw to target at /lib/firmware/hello_world/am62-mcu-m4f0_0-fw
    

    scp Release/am62-mcu-m4f0_0-fw target_62x:/lib/firmware/hello_world/am62-mcu-m4f0_0-fw
    

  • Reboot the target
  • Monitor the mcu uart. Should see lines like:
    

      0: Hello World!
      1: Hello World!
      2: Hello World!
      3: Hello World!
      4: Hello World!
      5: Hello World!
      6: Hello World!
      7: Hello World!
      8: Hello World!
      9: Hello World!
     10: Hello World!
     11: Hello World!
    

    
    with a new line being printed every 5 seconds up to 1000 times

Summary¶

This wiki page has demonstrated the following:

• Building, running and debugging hello world on the M4 processorusing a JTAG connection within Code Composer Studio
• Starting the hello world program using remoteproc
• Starting a hello world program when booting the target.