Atmel AT91EB01, Руководство пользователя

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Setting Up the AT91EB01 Evaluation Board
3-6 AT91EB01 Evaluation Board User Manual
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“LOWER MEM” uses the bit A16 of the AT91M40400. The entire flash can be reached
by the AT91M40400, and the boot software at location 0x01000000 is executed at the
reset.
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“UPPER MEM” uses the Vcc. Only the upper 64K can be reached, at the location
defined by the application software executed at the reset.
It is important to note that the examples provided by the AT91 library set up the EBI with:
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Flash at address 0x01000000
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SRAM at address 0x02000000
Nevertheless, when SW1 is set with “UPPER_MEM”, these addresses are under user
application responsability.
At delivery, the flash is programmed with the following software:
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Boot from 0x01000000 up to 0x01001FFF,
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Angel from 0x01002000 up to 0x0100FFFF, and
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Demo application from 0x01010000 up to 0101FFFF.
3.7.2 Flash Write Access The upper 64K of the Flash can be overwritten by using the Flash downloader (see
“Using the Flash Downloader” on page 3-13) whatever the position of the switch SW1.
This can also be done by using Angel rather than the Embedded ICE.
The lower 64K are write protected whatever the position of the switch SW1. This is to
prevent the boot and Angel software stored in the lower 64K bytes from being erased.
Nevertheless, it is always possible to make this space unprotected by setting a jumper
or a link on the footprint J7.
Note: If the lower 64K are not protected, the user must be especially careful. Even
though one of the features of the boot is the ability to restore Angel, it cannot be
saved itself. Once it is overwritten, the only way to restore the Flash is to use an
Embedded ICE.
3.7.3 The Boot Software The boot software is started at the reset if SW1 is switched to ”LOWER MEM”.
It first initializes the EBI (see “Programmer’s Model” on page 4-1), then executes the
REMAP procedure (see the AT91M40400 datasheet), and then checks the state of the
buttons:
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If the button FIQ is pressed, all the LEDs are lit, and the Functional Test Software
(FTS) is activated
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If the button TIOB1 is pressed, the red LED is lit, and the SRAM downloader is
activated
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If neither TIOB1 nor FIQ are pressed, the amber LED is lit and Angel is activated.
The code sources of the boot software are included in the AT91 library in the folder
“<MyFolderAT91>\Tools\BootEb01”.
3.7.4 The Functional Test
Software (FTS) The FTS is a part of the boot software which allows testing of the AT91EB01. It is
started by the boot if the FIQ button is pressed at reset. At start of the FTS, the LEDs 1,
2 and 3 light up. The user must then release the FIQ button. The LEDs switch off, and
then blink once.
The FTS then waits for one of the following user actions on the buttons:
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If the TIOB1 button is pressed, the memory size is checked and the green LED blinks:
- 1 = 256K bytes
- 2 = 512K bytes
- 3 = 1024K bytes
- 4 = 2048K bytes
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If the FIQ button is pressed, the USART are tested: