Getting Started with eCosTM
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# How to build and install the GDB module on the AEB-1

## Overview

The ARM AEB-1 comes with tools in ROM. These include a simple FLASH management tool and the Angel (R) monitor. eCos for the ARM AEB-1 comes with GDB stubs suitable for programming into the onboard FLASH. GDB is the preferred debug environment for eCos, but Angel must be used to initially install the GDB stubs.

Once this bootstrapping is done, you can use GDB to load and debug programs on the AEB-1 board.

The following steps will have you:

- talk to the AEB-1 board with a terminal emulator (or a real terminal!)

- enable ARM's Angel ROM monitor

- use GDB with Angel to download a configuration of eCos with GDB stubs which will act as a ROM monitor

- talk to the AEB-1 with a terminal emulator again, and tell it to write the new module to flash

- tell the board to use this new monitor, and then hook GDB up to it for real debugging

## Talking to the board

Connect a terminal or computer's serial port to the ARM AEB-1. On a PC with a 9-pin serial port, you can use the cable shipped by ARM with no modification.

Set the terminal or terminal emulator to 9600N1 (9600 baud, no parity, 1 stop bit).

Reset the board by pressing the little reset button on the top. You will see the following text:

    	ARM Evaluation Board Boot Monitor 0.01 (19 APR 1998)
    	Press ENTER within 2 seconds to stop autoboot

Press ENTER quickly, and you will get the boot prompt:

    	Boot:

## Downloading the GDB stubs

Run the angel monitor by typing the following at the Boot: prompt:

        Boot: plugin angel
        Boot: angel

Then exit the terminal emulator and start up gdb with the GDB module:

        $ arm-elf-gdb -nw loaders/arm-aeb/gdb_module.img
        (gdb) set remotebaud 9600
        (gdb) target rdi s=<YOUR SERIAL PORT>

On Windows, the serial port could be com1, com2, etc. On a UNIX or Linux system, the serial port would be /dev/cua0 or /dev/cua1. Examples are:

        (gdb) target rdi s=com1
        (gdb) target rdi s=/dev/cua0

Finally, load the GDB stubs image:

        (gdb) load
        Loading section .rom_vectors, size 0x44 lma 0xc000
        Loading section .text, size 0x3544 lma 0xc044
        Loading section .rodata, size 0x164 lma 0xf588
        Loading section .data, size 0x110 lma 0xf6ec
        Start address 0xc044 , load size 14332
        Transfer rate: 12739 bits/sec.

(Note that the sizes may not exactly match the ones you see on your system.)

Once the loading is done, quit GDB:

        (gdb) quit

## Activating the GDB stubs

Connect a terminal emulator to the board again, reset the board, and type enter within two seconds to get the Boot: prompt. This is the same thing you did at the beginning of this procedure.

Commit the GDB stubs module to flash:

    	Boot: flashwrite 4018000 C000 8000

Verify that the eCos/"GDB stubs" module is now added in the list of modules in the board:

    	Boot: rommodules

You should see the following output:

    	Header   Base     Limit
    	04000004 04000000 040034a8 BootStrap       1.00 (14 Aug 1998)
    	04003a74 04003800 04003bc0 Production Test 1.00 (13 Aug 1998)
    	0400e4f4 04004000 0400e60f Angel           1.02 (12 MAY 1998)
    	0401ac00 04018000 0401aed8 eCos            1.2  (26 Feb 1999) GDB stubs

Now make the eCos/"GDB stubs" module be the default monitor:

    	Boot: plugin eCos

## Running and debugging an application

Configure eCos from scratch for the ARM AEB-1 platform, and build your application. Remember that the AEB-1 board only has 128K of RAM.

Exit from the terminal emulator (you will not need it anymore for normal operations), and run gdb:

        $ arm-elf-gdb -nw executable
        (gdb) set remotebaud 38400
        (gdb) target remote <YOUR SERIAL PORT>
        (gdb) load

You can now run your program in the usual way under GDB'S control

Notice that the GDB stub runs at 38400 baud.

## Building the GDB stubs

We provide the GDB stubs image in the directory loaders/arm-aeb/gdb_module.img, but here are instructions on how to rebuild them if you should ever need to.

1. Configure a minimal eCos system with all packages except 'infra' disabled. If you are doing manual configuration, you can do so with

          tcl /work2/ecc/ecc/pkgconf.tcl                                         \
             --target=arm --platform=aeb --startup=stubs                         \
             --disable CYGPKG_KERNEL --disable CYGPKG_UITRON                     \
             --disable CYGPKG_LIBC --disable CYGPKG_LIBM                         \
             --disable CYGPKG_ERROR --disable CYGPKG_IO                          \
             --disable CYGPKG_IO_SERIAL --disable CYGPKG_DEVICES_WALLCLOCK       \
             --disable CYGPKG_DEVICES_WATCHDOG

   and if you are using the Configuration Tool GUI, you can select the ARM AEB platform, with GDB stubs startup, and enable the HAL and INFRA packages and disable all other packages.

2. Edit <hal/hal.h> to enable GDB:

           #define  CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
           #undef   CYGDBG_HAL_DEBUG_GDB_BREAK_SUPPORT
           #undef   CYGDBG_HAL_DEBUG_GDB_THREAD_SUPPORT

   you can use the following patch:

       --- pkgconf/hal.h~      Wed Mar 10 13:08:58 1999
       +++ pkgconf/hal.h       Thu Mar 11 15:53:16 1999
       @@ -356,9 +356,9 @@

           }}CFG_DATA */

       -#undef   CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
       +#define  CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
        #undef   CYGDBG_HAL_DEBUG_GDB_BREAK_SUPPORT
       -#define  CYGDBG_HAL_DEBUG_GDB_THREAD_SUPPORT
       +#undef   CYGDBG_HAL_DEBUG_GDB_THREAD_SUPPORT

        /*
         * NOTE:

3.     make misc

   The gdb_module.img file will be built in the directory hal/arm/aeb/current/misc

## Alternate way of loading the initial stubs

Using the AEB-1 module tool, install the GDB stubs from the provided ".UU" file.

> Note: This is an annotated 'terminal' session with the AEB-1 monitor:

    ARM Evaluation Board Boot Monitor 0.01 (19 APR 1998)
    Press ENTER within 2 seconds to stop autoboot
    Boot: help
    Module is BootStrap       1.00 (14 Aug 1998)

    Help is available on:
      Help          Modules       ROMModules    UnPlug        PlugIn
      Kill          SetEnv        UnSetEnv      PrintEnv      DownLoad
      Go            GoS           Boot          PC            FlashWrite
      FlashLoad     FlashErase

    Boot: download c000
    Ready to download. Use 'transmit' option on terminal emulator to download file.

     ... at this point, download the ASCII file "loaders/arm-aeb/gdb_module.img.UU".
     The details of this operation differ depending on which terminal emulator is used.
     It may be necessary to enter "^D" (control+D) when the download completes to
     get the monitor to return to command mode.

    Loaded file gdb_module.img.raw at address 0000c000, size = 13905

    Boot: flashwrite 4018000 c000 4000

      As above, this command actually programs the FLASH.

    Boot: rommodules
    Header   Base     Limit
    04000004 04000000 040034a8 BootStrap       1.00 (14 Aug 1998)
    04003a74 04003800 04003bc0 Production Test 1.00 (13 Aug 1998)
    0400e4f4 04004000 0400e60f Angel           1.02 (12 MAY 1998)
    0401b608 04018000 0401b844 eCos            1.2  (26 Feb 1999) GDB stubs

      This verifies that the eCos GDB stubs are available in FLASH.

    Boot: plugin ecos

      This makes the eCos GDB stubs the default "monitor."  When reset the
      AEB-1 will start the GDB stubs, after the initial 2 second escape
      period.

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