Actel Fusion Mixed-Signal FPGAs
The following error indications are possible for Read operations:
1. STATUS = '01' when a single-bit data error was detected and corrected within the block
addressed.
2. STATUS = '10' when a double-bit error was detected in the block addressed (note that the
error is uncorrected).
In addition to data reads, users can read the status of any page in the FB by asserting PAGESTATUS
along with REN. The format of the data returned by a page status read is shown in Table 2-23, and
the definition of the page status bits is shown in Table 2-24.
Table 2-23 • Page Status Read Data Format
31
8
7
4
3
2
1
0
Write Count Reserved Over Threshold Read Protected Write Protected Overwrite Protected
Table 2-24 • Page Status Bit Definition
Page Status Bit(s)
Definition
31–8
7–4
3
The number of times the page addressed has been programmed/erased
Reserved; read as 0
Over Threshold indicator (see the"Program Operation" section on page 2-47)
2
Read Protected; read protect bit for page, which is set via the JTAG interface
and only affects JTAG operations. This bit can be overridden by using the
correct user key value.
1
0
Write Protected; write protect bit for page, which is set via the JTAG interface
and only affects JTAG operations. This bit can be overridden by using the
correct user key value.
Overwrite Protected; designates that the user has set the OVERWRITEPROTECT
bit on the interface while doing a Program operation. The page cannot be
written without first performing an Unprotect Page operation.
Preliminary v1.7
2-51
ACTEL [ Actel Corporation ]
