afs600 Actel Corporation, afs600 Datasheet - Page 62

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Unprotect Page Operation
An Unprotect Page operation will clear the protection
for a page addressed on the ADDR input. It is initiated by
setting the UNPROTECTPAGE signal on the interface
along with the page address on ADDR.
If the page is not in the Page Buffer, the Unprotect Page
operation will copy the page into the Page Buffer. The
Figure 2-41 • FB Unprotected Page Waveform
The Unprotect Page operation can incur the following
error conditions:
Figure 2-42 • FB Discard Page Waveform
2 -4 8
Actel Fusion Programmable System Chips
1. If the copy of the page to the Page Buffer
2. If the address on ADDR does not match the
determines that the page has a single-bit
correctable error in the data, it will report a
STATUS = '01'.
address of the Page Buffer, PAGELOSSPROTECT is
asserted, and the Page Buffer has been modified,
then STATUS = '11' and the addressed page is not
loaded into the Page Buffer.
DISCARDPAGE
UNPROTECTPAGE
STATUS[1:0]
ADDR[17:0]
BUSY
CLK
BUSY
CLK
Page
A d v a n c e d v 1 . 4
Copy Page operation occurs only if the current page in
the Page Buffer is not Page Loss Protected.
The waveform for an Unprotect Page operation is shown
in
Discard Page Operation
If the contents of the modified Page Buffer have to be
discarded, the DISCARDPAGE signal should be asserted.
This command results in the Page Buffer being marked as
unmodified.
The timing for the operation is shown in
BUSY signal will remain asserted until the operation has
completed.
Figure
3. If the copy of the page to the Page Buffer
determines that at least one block in the page has
a double-bit uncorrectable error, STATUS = '10' and
the Page Buffer will contain the corrupted data.
2-41.
Valid
Figure
2-42. The