| The HAL Port | ||
|---|---|---|
 | Chapter 241. Atmel AT91SAM7A2-EK Board Support |  |
Name
HAL Port — Implementation Details
Overview
This documentation explains how the eCos HAL specification has been mapped onto the AT91SAM7A2-EK hardware, and should be read in conjunction with that specification. The AT91SAM7A2-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:
- Flash
- This is located at address 0x40000000 of the physical memory space.
- RAM
- This is located at address 0x48000000 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 0x48008000, with the bottom 32KiB reserved for use by RedBoot.
- 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.
Example 241.1. at91sam7a2ek Real-time characterization
Startup, main stack : stack used 416 size 3920
Startup : Interrupt stack used 148 size 4096
Startup : Idlethread stack used 88 size 2048
eCos Kernel Timings
Notes: all times are in microseconds (.000001) unless otherwise stated
Reading the hardware clock takes 1 'ticks' overhead
... this value will be factored out of all other measurements
Clock interrupt took 61.00 microseconds (57 raw clock ticks)
Testing parameters:
Clock samples: 32
Threads: 10
Thread switches: 128
Mutexes: 32
Mailboxes: 32
Semaphores: 32
Scheduler operations: 128
Counters: 32
Flags: 32
Alarms: 32
Confidence
Ave Min Max Var Ave Min Function
====== ====== ====== ====== ========== ========
46.93 43.73 50.13 1.71 40% 30% Create thread
8.96 8.53 9.60 0.51 60% 60% Yield thread [all suspended]
9.28 8.53 9.60 0.45 70% 30% Suspend [suspended] thread
10.03 9.60 10.67 0.51 60% 60% Resume thread
13.87 13.87 13.87 0.00 100% 100% Set priority
1.49 1.07 2.13 0.51 60% 60% Get priority
32.00 32.00 32.00 0.00 100% 100% Kill [suspended] thread
9.07 8.53 9.60 0.53 100% 50% Yield [no other] thread
16.96 16.00 17.07 0.19 90% 10% Resume [suspended low prio] thread
9.60 9.60 9.60 0.00 100% 100% Resume [runnable low prio] thread
12.80 12.80 12.80 0.00 100% 100% Suspend [runnable] thread
8.96 8.53 9.60 0.51 60% 60% Yield [only low prio] thread
9.17 8.53 9.60 0.51 60% 40% Suspend [runnable->not runnable]
32.00 32.00 32.00 0.00 100% 100% Kill [runnable] thread
23.15 22.40 23.47 0.45 70% 30% Destroy [dead] thread
46.51 45.87 46.93 0.51 60% 40% Destroy [runnable] thread
62.29 60.80 69.33 1.41 60% 90% Resume [high priority] thread
24.07 23.47 32.00 0.59 50% 49% Thread switch
1.60 1.07 2.13 0.53 100% 50% Scheduler lock
6.93 6.40 7.47 0.53 100% 50% Scheduler unlock [0 threads]
6.93 6.40 7.47 0.53 100% 50% Scheduler unlock [1 suspended]
6.93 6.40 7.47 0.53 100% 50% Scheduler unlock [many suspended]
6.93 6.40 7.47 0.53 100% 50% Scheduler unlock [many low prio]
2.67 2.13 3.20 0.53 100% 50% Init mutex
10.40 9.60 10.67 0.40 75% 25% Lock [unlocked] mutex
11.73 11.73 11.73 0.00 100% 100% Unlock [locked] mutex
9.87 9.60 10.67 0.40 75% 75% Trylock [unlocked] mutex
8.47 7.47 8.53 0.12 93% 6% Trylock [locked] mutex
1.07 1.07 1.07 0.00 100% 100% Destroy mutex
62.57 61.87 62.93 0.48 65% 34% Unlock/Lock mutex
3.53 3.20 4.27 0.46 68% 68% Create mbox
1.00 0.00 1.07 0.12 93% 6% Peek [empty] mbox
11.73 11.73 11.73 0.00 100% 100% Put [first] mbox
1.00 0.00 1.07 0.12 93% 6% Peek [1 msg] mbox
11.20 10.67 11.73 0.53 100% 50% Put [second] mbox
1.00 0.00 1.07 0.12 93% 6% Peek [2 msgs] mbox
11.67 10.67 11.73 0.12 93% 6% Get [first] mbox
11.60 10.67 11.73 0.23 87% 12% Get [second] mbox
9.53 8.53 9.60 0.12 93% 6% Tryput [first] mbox
8.93 8.53 9.60 0.50 62% 62% Peek item [non-empty] mbox
10.40 9.60 10.67 0.40 75% 25% Tryget [non-empty] mbox
8.73 8.53 9.60 0.32 81% 81% Peek item [empty] mbox
9.13 8.53 9.60 0.52 56% 43% Tryget [empty] mbox
1.13 1.07 2.13 0.12 93% 93% Waiting to get mbox
1.13 1.07 2.13 0.12 93% 93% Waiting to put mbox
3.47 3.20 4.27 0.40 75% 75% Delete mbox
43.40 42.67 43.73 0.46 68% 31% Put/Get mbox
2.27 2.13 3.20 0.23 87% 87% Init semaphore
8.60 8.53 9.60 0.12 93% 93% Post [0] semaphore
9.60 9.60 9.60 0.00 100% 100% Wait [1] semaphore
8.00 7.47 8.53 0.53 100% 50% Trywait [0] semaphore
8.33 7.47 8.53 0.33 81% 18% Trywait [1] semaphore
2.47 2.13 3.20 0.46 68% 68% Peek semaphore
1.20 1.07 2.13 0.23 87% 87% Destroy semaphore
39.17 38.40 39.47 0.43 71% 28% Post/Wait semaphore
3.73 3.20 4.27 0.53 100% 50% Create counter
1.33 1.07 2.13 0.40 75% 75% Get counter value
1.33 1.07 2.13 0.40 75% 75% Set counter value
10.20 9.60 10.67 0.52 56% 43% Tick counter
1.27 1.07 2.13 0.32 81% 81% Delete counter
2.27 2.13 3.20 0.23 87% 87% Init flag
9.13 8.53 9.60 0.52 56% 43% Destroy flag
7.93 7.47 8.53 0.52 56% 56% Mask bits in flag
9.53 8.53 9.60 0.12 93% 6% Set bits in flag [no waiters]
13.87 13.87 13.87 0.00 100% 100% Wait for flag [AND]
13.60 12.80 13.87 0.40 75% 25% Wait for flag [OR]
13.93 13.87 14.93 0.12 93% 93% Wait for flag [AND/CLR]
13.73 12.80 13.87 0.23 87% 12% Wait for flag [OR/CLR]
0.93 0.00 1.07 0.23 87% 12% Peek on flag
5.97 5.33 6.40 0.51 59% 40% Create alarm
17.60 17.07 18.13 0.53 100% 50% Initialize alarm
8.23 7.47 8.53 0.43 71% 28% Disable alarm
16.23 16.00 17.07 0.36 78% 78% Enable alarm
9.87 9.60 10.67 0.40 75% 75% Delete alarm
11.87 11.73 12.80 0.23 87% 87% Tick counter [1 alarm]
74.13 73.60 74.67 0.53 100% 50% Tick counter [many alarms]
22.67 22.40 23.47 0.40 75% 75% Tick & fire counter [1 alarm]
452.10 450.13 504.53 3.28 96% 96% Tick & fire counters [>1 together]
85.70 85.33 86.40 0.48 65% 65% Tick & fire counters [>1 separately]
58.67 58.67 58.67 0.00 100% 100% Alarm latency [0 threads]
65.02 58.67 72.53 3.94 42% 30% Alarm latency [2 threads]
64.89 58.67 72.53 3.99 42% 35% Alarm latency [many threads]
100.33 100.27 108.80 0.13 99% 99% Alarm -> thread resume latency
10.68 10.67 11.73 0.00 Clock/interrupt latency
24.98 21.33 146.13 0.00 Clock DSR latency
274 232 292 (main stack: 804) Thread stack used (1360 total)
All done, main stack : stack used 804 size 3920
All done : Interrupt stack used 208 size 4096
All done : Idlethread stack used 252 size 2048
Timing complete - 30940 ms total
PASS:<Basic timing OK>
EXIT:<done>Other Issues
The AT91SAM7A2-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.
| |  | |
| JTAG debugging support |  | Chapter 242. Atmel AT91SAM7A3-EK Board Support |
| 2024-12-10 | eCosPro Non-Commercial Public License |