Embedded NVM (eNVM) Controllers
UG0331 User Guide Revision 15.0
148
5.2.2
Data Retention Time
The following table shows the retention time of the eNVM with respect to the number of programming
cycles. The same values are applicable for both commercial and industrial SmartFusion2 product
grades. Refer to
DS0128: IGLOO2 FPGA and SmartFusion2 SoC FPGA Datasheet
on Programming cycles and retention time.
Note:
The eNVM is not prevented from programming, even if a page exceeds the write count threshold. The
eNVM Controller generates a flag through Status register.
5.2.3
eNVM Access Time
Refer to the
Embedded NVM (eNVM) Characteristics
SmartFusion2 SoC FPGA Datasheet
for eNVM Maximum Read Frequency and eNVM Page
Programming Time.
5.2.4
Theory of Operation
The eNVM AHB Controller supports the following operations:
•
Interface from AHBL for read, write, and erase operations
•
Issues all eNVM commands through AHBL read and write bus operation. The data width to and from
AHBL bus is 32 bits, and data to and from eNVM is 64 bits.
•
AB can be read directly from AHBL bus.
•
eNVMs treated as ROM. AHBL write transactions to eNVM user data array receive errors on
HRESP and write will be ignored.
•
Page Program command is used to write the NVM user data array.
•
AB can be written directly or loaded from the write data buffer (WDBUFF). Data can be written to
WDBUFF in byte, half-word or word AHB transfers.
•
Data for Page Program comes from WDBUFF or user data previously written into AB.
•
Command code in
page 151 determines the NVM commands to be issued. The eNVM
user data array is treated as ROM, so any program operations must be performed by submitting
relevant commands to the controller. Any AHBL writes to NVM user data without a valid NVM
command will cause the HRESP signal to be asserted on the AHBL bus. Any data that needs to be
written into the NVM user array must be uploaded first to the WDBUFF and then written into the
NVM user array through the assembly buffer. Program operation for the NVM user array occurs at
the page boundaries.
5.2.4.1
Write Control
The data to be programmed into eNVM must first be uploaded into WDBUFF due to the width difference
between the AHBL bus and the eNVM. Data can be written into WDBUFF by word, half-word, or byte
from the AHBL bus. ProgramDa and ProgramADS commands take care of uploading data into AB from
WDBUFF before programming eNVM.
Data is sent to eNVM from WDBUFF in chunks of double words (64 bits). Subsequent data transfer
commands to the AB and then to eNVM array, or commands such as ProgramAd, ProgramDa, and
ProgramStart, must specify the page address and upload data to AB to start eNVM array programming.
Refer to
page 151 for more information on commands.
Table 95 •
Data Retention Time
Programming Cycles Per eNVM Page
Retention
< 1000
20 years
< 10000
10 years
Содержание SmartFusion2 MSS
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Страница 166: ...Cortex M3 Processor Reference Material UG0331 User Guide Revision 15 0 132 ...
Страница 200: ...Embedded NVM eNVM Controllers UG0331 User Guide Revision 15 0 166 Figure 87 System Builder Window ...
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