Fusion Device Family Overview
flash operation without wait states. The memory block is organized in pages and sectors. Each
page has 128 bytes, with 33 pages comprising one sector and 64 sectors per block. The flash block
can support multiple partitions. The only constraint on size is that partition boundaries must
coincide with page boundaries. The flexibility and granularity enable many use models and allow
added granularity in programming updates.
Fusion devices support two methods of external access to the flash memory blocks. The first
method is a serial interface that features a built-in JTAG-compliant port, which allows in-system
programmability during user or monitor/test modes. This serial interface supports programming of
an AES-encrypted stream. Secure data can be passed through the JTAG interface, decrypted, and
then programmed in the flash block. The second method is a soft parallel interface.
FPGA logic or an on-chip soft microprocessor can access flash memory through the parallel
interface. Since the flash parallel interface is implemented in the FPGA fabric, it can potentially be
customized to meet special user requirements. For more information, refer to the
The flash memory parallel interface provides configurable byte-wide (×8), word-wide
(×16), or dual-word-wide (×32) data port options. Through the programmable flash parallel
interface, the on-chip and off-chip memories can be cascaded for wider or deeper configurations.
The flash memory has built-in security. The user can configure either the entire flash block or the
small blocks to prevent unintentional or intrusive attempts to change or destroy the storage
contents. Each on-chip flash memory block has a dedicated controller, enabling each block to
operate independently.
The flash block logic consists of the following sub-blocks:
•
•
•
•
Flash block – Contains all stored data. The flash block contains 64 sectors and each sector
contains 33 pages of data.
Page Buffer – Contains the contents of the current page being modified. A page contains 8
blocks of data.
Block Buffer – Contains the contents of the last block accessed. A block contains 128 data
bits.
ECC Logic – The flash memory stores error correction information with each block to
perform single-bit error correction and double-bit error detection on all data blocks.
User Nonvolatile FlashROM
In addition to the flash blocks, Actel Fusion devices have 1 kbit of user-accessible, nonvolatile
FlashROM on-chip. The FlashROM is organized as 8×128-bit pages. The FlashROM can be used in
diverse system applications:
•
•
•
•
•
•
•
•
Internet protocol addressing (wireless or fixed)
System calibration settings
Device serialization and/or inventory control
Subscription-based business models (for example, set-top boxes)
Secure key storage for secure communications algorithms
Asset management/tracking
Date stamping
Version management
The FlashROM is written using the standard IEEE 1532 JTAG programming interface. Pages can be
individually programmed (erased and written). On-chip AES decryption can be used selectively over
public networks to securely load data such as security keys stored in the FlashROM for a user
design.
The FlashROM can be programmed (erased and written) via the JTAG programming interface, and
its contents can be read back either through the JTAG programming interface or via direct FPGA
core addressing.
The FlashPoint tool in the Actel Fusion development software solutions, Libero IDE and Designer,
has extensive support for flash memory blocks and FlashROM. One such feature is auto-generation
of sequential programming files for applications requiring a unique serial number in each part.
Another feature allows the inclusion of static data for system version control. Data for the
FlashROM can be generated quickly and easily using the Actel Libero IDE and Designer software
1 -6
Pr e li m i n a r y v1 . 7
ACTEL [ Actel Corporation ]
