AFS090 datasheet(69/334 Pages) MICROSEMI

69 / 334 page

Fusion Family of Mixed Signal FPGAs

R e visio n 2

2 - 53

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 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 Figure 2-42.

The Unprotect Page operation can incur the following error conditions:

1. If the copy of the page to the Page Buffer determines that the page has a single-bit correctable

error in the data, it will report a STATUS = '01'.

2. If the address on ADDR does not match the 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.

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.

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 Figure 2-43. The BUSY signal will remain asserted until the

operation has completed.

Figure 2-42 • FB Unprotected Page Waveform

CLK

UNPROTECTPAGE

ADDR[17:0]

BUSY

STATUS[1:0]

Page

Valid

Figure 2-43 • FB Discard Page Waveform

CLK

DISCARDPAGE

BUSY

AFS090 데이터시트(PDF) 69 Page - Microsemi Corporation