Programming Flash Devices
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development, programs a single device at a time and is referred to as a single-site engineering
programmer.
With ISP, the device is already mounted onto the board when programming occurs, most typically
via the JTAG pins. The JTAG pins can be controlled either by an on-board resource, such as a
microprocessor, or by an off-board programmer through a header connection. Once mounted, it
can be programmed repeatedly. If the application requires it, the system can be designed to
reprogram itself using a microprocessor, without the use of any external programmer.
For production, high-volume multi-site production programmers handle designs that require
device programmers. In addition, Actel can preprogram devices for production, negating the need
for further programming. This service is referred to as in-house programming (IHP).
Live at Power-Up (LAPU) or Boot PROM
Utilizing the technology of the FPGA significantly impacts board-level power-up considerations.
Some technologies are nonvolatile and are considered functional, or "live," as soon as power
reaches the operational level. All Actel FPGA technologies are live at power-up. By contrast, SRAM
technology is volatile, and devices built using SRAM cells lose their contents when power cycling
occurs. These devices must be reprogrammed every time power is applied. Such a design must
include nonvolatile storage for the contents as well as the means to reprogram. There is a delay
before SRAM devices are functional; other parts of the board must come alive first to reprogram
these types of FPGAs. Therefore, such devices can never be part of critical boot circuits.
Design Security
Design security is a growing concern for systems designers. The choice of programming
methodology and technology affects system security. Use of Actel programming technology is the
most secure option available, providing much better protection than SRAM-based devices and
ASICs. Actel provides a number of ways to ensure designs are protected. General information on
design security can be found on the Actel website:
Programming Features for Actel Devices
Actel provides two types of FPGAs: flash and antifuse (
Table 14-1). Some programming methods
are common to both and some are exclusive to flash. This document describes only the
programming solutions supported for flash devices.
Flash Devices
The flash devices supplied by Actel are reprogrammable by either a generic device programmer or
ISP. Actel supports ISP using JTAG, which is supported by the FlashPro3, FlashPro, FlashPro Lite, and
Sculptor programmers.
Levels of ISP support vary depending on the device chosen:
Fusion, ProASIC3, and ProASIC3E devices support ISP.
ProASIC3L devices operate using a 1.2 V core voltage and support ISP at 1.5 V only. Voltage
switching is required in-system to switch from a 1.2 V core to 1.5 V core for programming.
Table 14-1 Programming Features for Actel Devices
Feature
Flash
Antifuse
Reprogrammable
Yes
No
In-system programmable
Yes
No
One-time programmable
Yes (option)
Yes
Live at power-up
Yes
Secure
Yes
Single-site programmer support
Yes
Multi-site programmer support
Yes
In-house programming support
Yes