Development Environment Introduction i.MX6SoloX : A9 + M4 Development Environment Introduction 2014.03.21

Scope Develop the application for i.MX6SX Cortex-M4 core 6SX SDB as the target board Bare Metal Code (No OS) Development Tools Choices: GNU Toolchain ARM DS-5

Material 6SX SDB SD card & card reader Development Tool from GNU GNU Tools for ARM Embedded Processors x86 Linux Machine e.g. Ubuntu Development Tools from ARM ARM Development Studio 5, DS-5 MS Windows RealView ICE

6SX SDB SD4 boot USB for UART1 UART2 JTAG SW10 = 00000000

Download the Linux installation tarball: GNU Tools Download the Linux installation tarball: https://launchpad.net/gcc-arm-embedded

Linux Development Machine Setup Install the gnu tools tarball mkdir –p /opt/toolchain cd /opt/toolchain tar jxf gcc-arm-none-eabi-4_8-2013q4-20131204-linux.tar.tar.bz2 Version will be changed in future release Create the build environment setup script Let’s say the name of the script is “m4-build-env”, save it under ~/bin/ It contains: #!/bin/bash TOOLBIN=/opt/toolchain/gcc-arm-none-eabi-4_8-2013q4/bin export CROSS_COMPILE=$TOOLBIN/arm-none-eabi- export PATH=$PATH:$TOOLBIN bash

M4 Code Skeleton – linker script ENTRY(_reset) OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm") OUTPUT_ARCH(arm) MEMORY { TCML_ALIAS (rwx) : ORIGIN = 0x00000000, LENGTH = 32K } SECTIONS .vectors : *o(.vectors_) }>TCML_ALIAS .text : . = ALIGN (4); *(.text) .data : *(.data) .bss : *(.bss)

M4 Code Skeleton - vectors On system reset, the vector table is fixed at address 0x00000000 Address Vector 0x00000000 Initial SP value 0x00000004 Reset 0x00000008 NMI 0x0000000C Hard fault 0x00000010 Memory management fault 0x00000014 Bus fault 0x00000018 Usage fault Reserved 0x0000002C SVCall 0x00000038 PendSV 0x0000003C SysTick 0x00000040 IRQ0 0x00000044 IRQ1 . /* vectors.s */ .thumb .word 0x20007000 /* stack top address */ .word _reset /* 1 Reset */ .word hang /* 2 NMI */ .word hang /* 3 HardFault */ .word hang /* 4 MemManage */ .word hang /* 5 BusFault */ .word hang /* 6 UsageFault */ .word hang /* 7 RESERVED */ .word hang /* 8 RESERVED */ .word hang /* 9 RESERVED*/ .word hang /* 10 RESERVED */ .word hang /* 11 SVCall */ .word hang /* 12 Debug Monitor */ .word hang /* 13 RESERVED */ .word hang /* 14 PendSV */ .word SysTickHandler /* 15 SysTick */ .word hang /* 16 IRQ 0 */ .word hang /* 17 IRQ 1 */ .word hang /* 18 IRQ 2) */ .word hang /* 19 ... */ .thumb_func .global _reset _reset: mov r0, #0 ldr r1, [r0] mov sp, r1 bl main b hang hang: b .

M4 Code Skeleton int main(int argc, char ** argv) { … } void SysTickHandler(void)

Example code for M4 Purpose: To print “Hello World” on UART2 It is a bare metal code which can build under GNU toolchain under linux host The source include: Vector Table: vectors.s Link Script: cortex_m4.ld C code: main() … Usage tar zxf the m4_apps.tar.gz cd m4_apps m4-build-env make

Example code for M4 What the “make” does: Compile with “-mcpu=cortex-m4 -mthumb” options arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -c -g vectors.s -o vectors.o arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -c -g main.c -o main.o arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -c -g iomux-v3.c -o iomux-v3.o arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -c -g timer.c -o timer.o arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -c -g uart.c -o uart.o Link arm-none-eabi-ld -g -T cortex_m4.ld vectors.o main.o iomux-v3.o timer.o uart.o -o cortex_m4.elf - Extract the binary from elf arm-none-eabi-objcopy -O binary cortex_m4.elf cortex_m4.bin Convert cortex_m4.bin to m4_binary[ ] C char array It will be loaded to TCM by A9 echo "unsigned char M4_binary[] = {" > m4_bin.h bin2chex cortex_m4.bin >> m4_bin.h echo "};" >> m4_bin.h

Basic Workflow The Cortex-M4 implementation includes two tightly coupled memories TCML, TCMH 32K Byte + 32K Byte Tasks for A9 Boot from any boot source (e.g. SD4) Setup the environment for M4 Enable the peripheral access for M4 Turn on M4 clock Load the M4 binary image to TCM The image included the vectors table for M4 Enable M4 and Release the reset for M4 Continue his business… After M4 Reset M4 jumps to the address according to the reset vector in 0x00000004 Branch to main() m4_binary[]

Note M4 core can access most of the peripherals, but the memory map is different from A9 For example: AIPS1, AIPS2 & AIPS3 have +0x4000000 offset in M4 Please check memory map chapter from the Reference Manual TCML Address for A9 is 0x007f8000 TCML Address for M4 is 0x1FFF8000 and alias at 0x00000000

Example Code for A9 to Launch M4 app unsigned char M4_binary[] = { 0x00, 0xe0, 0xff, 0x1f, 0x51, ………… } void m4_run_bin(unsigned char *bin, size_t size) { /* M4 access for all peripherals on the bus */ writel(0x77777777, 0x0207C000); writel(0x77777777, 0x0217C000); writel(0x77777777, 0x0227C000); /* M4 Clock On */ writel(readl(0x020c4074) | (0x3<<2), 0x020c4074); memcpy(TCM, bin, size); /* Enable M4 and Assert the soft reset */ writel(readl(0x020d8000) | (1<<22) | (1<<4), 0x020d8000); /* Release the reset for M4 */ writel(readl(0x020d8000) & ~(1<<4), 0x020d8000); void func(void) m4_run_bin(M4_binary, sizeof(M4_binary));

Workflow M4 apps source M4 apps .elf/.axf M4 apps binary A9 apps unsigned char M4_binary[ ] Compile & Link objcopy bin2chex A9 apps source SD Card boot A9 apps image Compile & Link dd the image to SD Card unsigned char M4_binary[ ] A9 loads the apps image to TCM A9 kicks off M4 to run the apps

Running The Demo Code Transfer the A9 binary to a SD card sudo dd if=output/mx6slx/smart_device_rev_a/bin/mx6slx-smart_device-reva-obds.bin of=/dev/sdb bs=1K skip=1 seek=1 && sync Connect “UART to USB” port to PC The port contains 2 devices UART1 for A9 UART2 for M4 Boot the card from SD4 port You should see “Hello World from Cortex-M4!” in UART2 port

ARM DS-5 Complete IDE Source Code Editor, Browser Compiler & Linker DS-5 Debugger Source Level Debug Can debug .elf file, which build by GNU tools for ARM Embedded Processors

DS-5 Setup: i.MX6 Solo X Debug Target Besides the DS-5 installation & software license, you also need the debug target files for 6SX Unzip attached files and copy them to: C:\Program Files\DS-5\sw\debugger\configdb\Boards\Freescale

ARM DS-5 Demo Video 01_Import_Project_Build.mp4 Import Existing Project Build the project Generate .axf – ARM Executable & Linkable Format file

ARM DS-5 Demo Video 02_Configure_DS-5_Debug.mp4 Open DS-5 Debugger Create 2 debug configurations for 6SX Connect A9 core, Run init script Set up the environment for M4 For the first connection after power up, the debugger cannot control the target and the init script failed to run The problem can be solved by “Interrupt”, then “Connect” once again Disconnect A9 Connect M4 core Load and Execute the apps Source Level Debugging Add/Toggle Breakpoint

ARM DS-5 Demo Video 03_Edit_Source_Build_Debug.mp4 Return to the project source code Edit Source Build Open DS-5 Debugger Connect the A9 then M4 Load and Execute the modified apps Debug the apps