eCosPro® Reference Manual
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# The HAL Port

## Name

HAL Port -- Implementation Details

## Overview

This documentation explains how the eCos HAL specification has been mapped onto the AT91SAM7A3-EK hardware, and should be read in conjunction with that specification. The AT91SAM7A3-EK platform HAL package complements the ARM architectural HAL, the AT91 variant HAL and the AT91SAM7 processor HAL. It provides functionality which is specific to the target board.

## Startup

Following a hard or soft reset, the HAL will initialize or reinitialize most of the on-chip peripherals. There is an exception for RAM startup applications which depend on a ROM monitor or JTAG device for certain services.

For ROM startup, the HAL will perform additional initialization, setting up the PLL and programming the various internal registers. This is all done in the `PLATFORM_SETUP1` macro in the assembler header file `hal_platform_setup.h`.

## Linker Scripts and Memory Maps

The AT91SAM7 processor HAL package provides the memory layout information needed to generate the linker script. The key memory locations are as follows:

On-chip Flash

  This is located at address 0x00100000 of the physical memory space.

On-chip RAM

  This is located at address 0x00200000 of the physical memory space. During booting this memory is only available at this address, but during the boot process it is also remapped to location 0x00000000 in order to allow the hardware exception vectors to be in RAM. The first 32 bytes are used for hardware exception vectors. The next 32 bytes are used for the VSR table and the next 256 bytes are normally used for the eCos virtual vectors, allowing RAM-based applications to use services provided by the ROM monitor. For ROM startup, all remaining RAM is available. For RAM startup, available RAM starts at location 0x00201000, with the bottom 4KiB reserved for use by the GDB stubs.

On-chip Peripheral Registers

  These are located at address 0xFF000000 in the physical memory space.

## Real-time characterization

The tm_basic kernel test gives statistics gathered about the real-time characterization and performance of the kernel. The sample output is shown here for information. The test was built in ARM mode, which provided better performance than Thumb mode.

                Startup, main stack : stack used   456 size  3920
                 Startup :  Interrupt stack used  4064 size  4096
                 Startup : Idlethread stack used   120 size  2048

    eCos Kernel Timings
    Notes: all times are in microseconds (.000001) unless otherwise stated

    Reading the hardware clock takes 3 'ticks' overhead
    ... this value will be factored out of all other measurements
    Clock interrupt took   47.13 microseconds (141 raw clock ticks)

    Testing parameters:
       Clock samples:            32
       Threads:                   1
       Thread switches:         128
       Mutexes:                  32
       Mailboxes:                21
       Semaphores:               32
       Scheduler operations:    128
       Counters:                 32
       Flags:                    32
       Alarms:                   32

                                     Confidence
         Ave     Min     Max     Var  Ave  Min  Function
      ======  ======  ======  ====== ========== ========
      144.33  144.33  144.33    0.00  100% 100% Create thread
       18.33   18.33   18.33    0.00  100% 100% Yield thread [all suspended]
       14.67   14.67   14.67    0.00  100% 100% Suspend [suspended] thread
       14.67   14.67   14.67    0.00  100% 100% Resume thread
       17.33   17.33   17.33    0.00  100% 100% Set priority
        0.67    0.67    0.67    0.00  100% 100% Get priority
       32.33   32.33   32.33    0.00  100% 100% Kill [suspended] thread
       18.67   18.67   18.67    0.00  100% 100% Yield [no other] thread
       22.67   22.67   22.67    0.00  100% 100% Resume [suspended low prio] thread
       14.67   14.67   14.67    0.00  100% 100% Resume [runnable low prio] thread
       18.00   18.00   18.00    0.00  100% 100% Suspend [runnable] thread
       18.67   18.67   18.67    0.00  100% 100% Yield [only low prio] thread
       14.67   14.67   14.67    0.00  100% 100% Suspend [runnable->not runnable]
       32.00   32.00   32.00    0.00  100% 100% Kill [runnable] thread
       31.33   31.33   31.33    0.00  100% 100% Destroy [dead] thread
       55.67   55.67   55.67    0.00  100% 100% Destroy [runnable] thread
      106.67  106.67  106.67    0.00  100% 100% Resume [high priority] thread

        0.85    0.67    1.00    0.16   56%  43% Scheduler lock
       13.31   13.00   13.33    0.04   93%   6% Scheduler unlock [0 threads]
       13.31   13.00   13.33    0.04   93%   6% Scheduler unlock [1 suspended]
       13.31   13.00   13.33    0.04   93%   6% Scheduler unlock [many suspended]
       13.31   13.00   13.33    0.04   93%   6% Scheduler unlock [many low prio]

        2.33    2.33    2.33    0.00  100% 100% Init mutex
       18.58   18.33   18.67    0.13   75%  25% Lock [unlocked] mutex
       20.68   20.67   21.00    0.02   96%  96% Unlock [locked] mutex
       16.58   16.33   16.67    0.13   75%  25% Trylock [unlocked] mutex
       15.96   15.67   16.00    0.07   87%  12% Trylock [locked] mutex
        1.00    1.00    1.00    0.00  100% 100% Destroy mutex
       85.56   85.33   85.67    0.14   68%  31% Unlock/Lock mutex

        3.90    3.67    4.00    0.14   71%  28% Create mbox
        0.29    0.00    0.33    0.08   85%  14% Peek [empty] mbox
       19.90   19.67   20.00    0.14   71%  28% Put [first] mbox
        0.33    0.33    0.33    0.00  100% 100% Peek [1 msg] mbox
       19.92   19.67   20.00    0.12   76%  23% Put [second] mbox
        0.33    0.33    0.33    0.00  100% 100% Peek [2 msgs] mbox
       20.00   20.00   20.00    0.00  100% 100% Get [first] mbox
       20.00   20.00   20.00    0.00  100% 100% Get [second] mbox
       18.92   18.67   19.00    0.12   76%  23% Tryput [first] mbox
       16.49   16.33   16.67    0.17   52%  52% Peek item [non-empty] mbox
       17.49   17.33   17.67    0.17   52%  52% Tryget [non-empty] mbox
       16.33   16.33   16.33    0.00  100% 100% Peek item [empty] mbox
       16.56   16.33   16.67    0.15   66%  33% Tryget [empty] mbox
        0.40    0.33    0.67    0.10   80%  80% Waiting to get mbox
        0.40    0.33    0.67    0.10   80%  80% Waiting to put mbox
        2.16    2.00    2.33    0.17   52%  52% Delete mbox
       68.73   68.67   69.00    0.10   80%  80% Put/Get mbox

        2.33    2.33    2.33    0.00  100% 100% Init semaphore
       14.00   14.00   14.00    0.00  100% 100% Post [0] semaphore
       14.50   14.33   14.67    0.17  100%  50% Wait [1] semaphore
       13.96   13.67   14.00    0.07   87%  12% Trywait [0] semaphore
       14.00   14.00   14.00    0.00  100% 100% Trywait [1] semaphore
        2.38    2.33    2.67    0.07   87%  87% Peek semaphore
        0.83    0.67    1.00    0.17  100%  50% Destroy semaphore
       58.07   58.00   58.33    0.11   78%  78% Post/Wait semaphore

        4.00    4.00    4.00    0.00  100% 100% Create counter
        0.46    0.33    0.67    0.16   62%  62% Get counter value
        0.46    0.33    0.67    0.16   62%  62% Set counter value
       15.46   15.33   15.67    0.16   62%  62% Tick counter
        0.50    0.33    0.67    0.17  100%  50% Delete counter

        2.25    2.00    2.33    0.13   75%  25% Init flag
       14.33   14.33   14.33    0.00  100% 100% Destroy flag
       13.75   13.67   14.00    0.13   75%  75% Mask bits in flag
       15.67   15.67   15.67    0.00  100% 100% Set bits in flag [no waiters]
       19.83   19.67   20.00    0.17  100%  50% Wait for flag [AND]
       19.58   19.33   19.67    0.13   75%  25% Wait for flag [OR]
       19.83   19.67   20.00    0.17  100%  50% Wait for flag [AND/CLR]
       19.58   19.33   19.67    0.13   75%  25% Wait for flag [OR/CLR]
        0.25    0.00    0.33    0.13   75%  25% Peek on flag

        5.27    5.00    5.33    0.10   81%  18% Create alarm
       20.54   20.33   20.67    0.16   62%  37% Initialize alarm
       13.90   13.67   14.00    0.14   68%  31% Disable alarm
       19.85   19.67   20.00    0.16   56%  43% Enable alarm
       14.65   14.33   14.67    0.04   93%   6% Delete alarm
       17.42   17.33   17.67    0.13   75%  75% Tick counter [1 alarm]
       82.65   82.33   82.67    0.04   93%   6% Tick counter [many alarms]
       26.08   26.00   26.33    0.13   75%  75% Tick & fire counter [1 alarm]
      371.00  369.67  402.67    1.98   96%  96% Tick & fire counters [>1 together]
       91.63   91.33   91.67    0.07   87%  12% Tick & fire counters [>1 separately]
       38.33   38.33   38.33    0.00  100% 100% Alarm latency [0 threads]
       40.89   38.33   44.67    2.44   27%  47% Alarm latency [many threads]
       93.75   93.67  104.67    0.17   99%  99% Alarm -> thread resume latency

        6.66    6.33    6.67    0.00            Clock/interrupt latency

       14.37   13.00  261.33    0.00            Clock DSR latency

     1360   1360    1360  (main stack:  3920)  Thread stack used (1360 total)
               All done, main stack : stack used   896 size  3920
                All done :  Interrupt stack used   212 size  4096
                All done : Idlethread stack used   304 size  2048

    Timing complete - 23730 ms total

    PASS:<Basic timing OK>
    EXIT:<done>

## Other Issues

The AT91SAM7A3-EK platform HAL does not affect the implementation of other parts of the eCos HAL specification. The AT91SAM7 processor HAL, AT91 variant HAL, and the ARM architectural HAL documentation should be consulted for further details.

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