Notes /Axle /6 Axis Arm

6 Axis Arm

Contents

RTOS
Limit where bare metal runs
Tell BSP that CPU1 is an AMP secondary core
Run .elf on only one cpu
Servo high inrush current
Index

Memory reserved for shared purpose is 0x1e00000 with size 0x10000 Memory reserved for rtos is 0x1e010000 with size 0x1ff0000

CPU0 runs petalinux CPU1 runs RTOS

§RTOS

You must first create platform with cortex1. Ensure you are using the same .xsa file as the one used for creating petalinux project for Application. You're not running bare-metal "on the fabric." You're running bare-metal on the ARM processor, and the ARM talks to hardware you've built in the fabric.

§Limit where bare metal runs

Go find lscript.ld in your application directory. It should be inside src folder. Create a new available memory space called rtos_mem_ps with base address 0x1E010000 with size 0x1FF0000. This should match what area of memory is reserved by petalinux. Set all sections of the memory to use rtos_mem_ps

§Tell BSP that CPU1 is an AMP secondary core

Go click on Platform project (eg. jinnysus_led)
double click on platform.spr to open platform configuration window
Look for "ps_cortexa9_1" on the left nav -> "Board Support Package" -> Modify BSP Settings. Go to drivers -> ps7_cortexa9_1. You should see a configuration name "extra_compiler_flags". Append a space and then add exactly this macro to the existing flags:

-DUSE_AMP=1

Click okay

§Why this works

SMP (Symmetric Multiprocessing): This is what your phone or laptop does. All CPU cores are bundled together under one operating system. OS treats all cores equally AMP (Asymmetric Multiprocessing): This is when different cores are controlled by different operating system. By setting "Define: Use_AMP equals True (1)", we are telling vitis we force compiler to skip these danger lines

#ifndef USE_AMP
    // If USE_AMP is NOT defined, assume we own the whole house!
    Initialize_Global_Caches();
    Overwrite_MMU_Tables();
#endif

§Run .elf on only one cpu

Make sure you have clean and built application project. Power cycle if need to. Open up XSCT Console

targets 3
dow "D:/Work/projects/zybo_z7_projects/lab3_vitis_workspace/{application_name}/Debug/{application_name}.elf"
con

Note: APU Application Processing Unit (target 1) ARM Cortex-A9 MPCore #0 (target 2) ARM Cortex-A9 MPCore #1 (target 3)

Note: target 0 is the Whole Chip Level Debugger (or the JTAG Cable / Whole Chain itself).

§Servo high inrush current

Commanding the servo to move from $180^\circ$ to $10^\circ$ will attempt to turn at full torque to bridge the $170^\circ$ gap as fast as possible. This causes a spike in power draw. This will possibly disconnect USB to UART connection as all the power flows to the servo to meet that demand TLDR, motors use a lot of energy, have external power source for your motors to prevent brownout.