Atmel AT32UC3C0128C, Руководство пользователя

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32166A–AVR32806–06/11
Atmel AVR32806
mine the frequency of the clock input on Osc0. Trying to communicate with the ISP before it is
detected by the PC OS as a USB device will fail.
7.3 Customizing the ISP configuration words
The purpose of this section is to propose a method for computing ISP Configuration Word1 and
Configuration Word2 for a given set of (ISP_IO_COND_PIN, ISP_IO_COND_LEVEL) values
(refer to
Section 6.2.2
for a detailled description of the ISP configuration words stored in the user
page).
7.3.1 ISP Configuration Word1
7.3.1.1 Step 1: Setting the ISP_BOOT_KEY_1 field
As mentioned in
Table 6-1.,
the ISP_BOOT_KEY_1 field must always be set to 0xE11E at offset
16. At this step, Configuration Word1 is always 0xE11E****.
7.3.1.2 Step 2: Setting the Reserved field
As mentioned in
Table 6-1.
, the reserved field must always be set to 0x3F at offset 10. At this
step, Configuration Word1 is always 0xE11EFC**, with bits 9 and 8 unset.
7.3.1.3 Step 3: Setting the ISP_FORCE field
As mentioned in
Table 6-1.,
the ISP_FORCE field is either activated (1) or not (0), and set at bit
9 of ISP Configuration Word1.
When ISP_FORCE is set to 1, ISP Configuration Word1 is always 0xE11EFE** (with bit 8 not set
yet).
Otherwise, ISP Configuration Word1 is always 0xE11EFC** (with bit 8 not set yet).
7.3.1.4 Step 4: Setting the ISP_IO_COND_EN field
As mentioned in
Table 6-1.,
the ISP_IO_COND_EN field is either enabled (1) or disabled (0),
and set at bit 8 of ISP Configuration Word1.
If ISP_FORCE is not set, ISP Configuration Word1 is then 0xE11EFD.
7.3.1.5 Step 5: Setting the ISP_CRC8_1 field
As mentioned in
Table 6-1.,
the ISP_CRC8_1 value is the CRC of the three other bytes of ISP
Configuration Word1.
Using the example from step 4, the CRC8 of 0xE11EFD is 0xD9. ISP Configuration Word1
would then be 0xE11EFDD9.
There are several methods to compute a CRC8, and several resources are available on the web
f o r t h i s p u r p o s e . F o r e x a m p l e , t o u s e t h e J a v a
®
a p p l e t o n t h e s i t e ,
http://www.smbus.org/faq/crc8Applet.htm
, fill in the “Enter hex-coded message...” field with
E11EFD, press the OK button, and then read the “Frame Check Sequence...” field that contains
the CRC8 value (“Frame Check = 0xd9”).
7.3.1.6 Step 6: Program ISP Configuration Word1 to the user page
• Using avr32program: