Adaptec AVA-1505A Betriebsanweisung PDF herunterladen (Seite 26)

26 FAQ’s for Actel’s Antifuse FPGA Programming

69. How do I verify that a device has been programmed?

Ans. You can verify that an Actel FPGA has been programmed by placing it in any supported

programmer and running a blank check/Dev_Status. If the device is programmed then you will see Fuse

checksum in the Design Checksum. See figure 4 above.

70. How do I determine the status of the Actel security fuse?

Ans. To determine the status of the Actel security fuse, run Dev_Status. See figure 4.

71. What is the fuse checksum?

Ans. The fuse checksum is a four digit hexadecimal number programmed into all Actel devices at the end

of the programming sequence. This information can be used to match a programmed device to its

programming (*.afm) file. The fuse checksum is calculated from the fuses in the *.afm file and stored in

the device. This number is unique for each fuse map. This number can also change when the target die is

changed, even if no change is made to the layout of the device. The checksum is the last information

programmed to the device, which is the best way to ensure that all the information has been programmed

successfully.

72. Why do I see a different fuse checksum in the Axcelerator

*.afm file

when it is regenerated from 8.0 Sp2 or later?

Ans. Starting from 8.0 SP2, the checksum calculation of an AX/RTAX-S device includes IO CSR

(configuration shift register, responsible for I/O attributes) fuses. If you regenerate the *.afm file from an

older *.adb file, you will see a change in the checksum, even though nothing has changed. Previously,

only a layout change would trigger to change the checksum. When you change the I/O attribute (in MVN)

you do not need to run-layout. The layout button stays green, so the checksum remains the same.

With the new change, we are now calculating the checksum taking I/O attributes into consideration, so

that if there are any changes in I/O attributes, the change will be reflected in checksum.

However, as we are adding I/O fuse into calculation, even if there is no change in IO attribute, opening

Libero IDE 8.0 SP2 will change the checksum.

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