E
1.3
4-MBIT SmartVoltage BOOT BLOCK FAMILY
The 4-Mbit flash memory products are also
excellent design solutions for digital cellular phone
and telecommunication switching applications
requiring very low power consumption, high-
performance, high-density storage capability,
modular software designs, and a small form factor
package. The 4-Mbit’s blocking scheme allows for
easy segmentation of the embedded code with
16 Kbytes of hardware-protected boot code, four
main blocks of program code and two parameter
blocks of 8 Kbytes each for frequently updated data
storage and diagnostic messages (e.g., phone
numbers, authorization codes).
Intel’s boot block architecture provides a flexible
voltage solution for the different design needs of
various applications. The asymmetrically-blocked
memory map allows the integration of several
memory components into a single flash device. The
boot block provides a secure boot PROM; the
parameter
blocks
can
emulate
EEPROM
functionality for parameter store with proper
software techniques; and the main blocks provide
code and data storage with access times fast
enough to execute code in place, decreasing RAM
requirements.
Applications
The 4-Mbit boot block flash memory family
combines
high-density,
low-power,
high-
performance, cost-effective flash memories with
blocking and hardware protection capabilities. Their
flexibility and versatility reduce costs throughout the
product life cycle. Flash memory is ideal for Just-In-
Time production flow, reducing system inventory
and costs, and eliminating component handling
during the production phase.
When your product is in the end-user’s hands, and
updates or feature enhancements become
necessary, flash memory reduces the update costs
by allowing user-performed code changes instead
of costly product returns or technician calls.
The 4-Mbit boot block flash memory family provides
full-function, blocked flash memories suitable for a
wide range of applications. These applications
include extended PC BIOS and ROM-able
applications storage, digital cellular phone program
and data storage, telecommunication boot/firmware,
printer firmware/font storage and various other
embedded applications where program and data
storage are required.
Reprogrammable systems, such as personal
computers, are ideal applications for the 4-Mbit
flash memory products. Increasing software
sophistication greatens the probability that a code
update will be required after the PC is shipped. For
example, the emerging of “plug and play” standard
in desktop and portable PCs enables auto-
configuration of ISA and PCI add-in cards.
However, since the “plug and play” specification
continues to evolve, a flash BIOS provides a cost-
effective capability to update existing PCs. In
addition, the parameter blocks are ideal for storing
the
required
auto-configuration
parameters,
allowing you to integrate the BIOS PROM and
parameter storage EEPROM into a single
component, reducing parts costs while increasing
functionality.
1.4
Pinouts
Intel’s SmartVoltage Boot Block architecture
provides upgrade paths in every package pinout to
the 8-Mbit density. The 28F004B 40-lead TSOP
pinout for space-constrained designs is shown in
Figure 3. The 28F400 44-lead PSOP pinout follows
the industry-standard ROM/EPROM pinout, as
shown in Figure 4. For designs that require x16
operation but have space concerns, refer to the
48-lead pinout in Figure 5. Furthermore, the 28F400
56-lead TSOP pinout shown in Figure 6 provides
density upgrades to future higher density boot block
memories.
Pinouts for the corresponding 2-Mbit and 8-Mbit
components are also provided for convenient
reference. 4-Mbit pinouts are given on the chip
illustration in the center, with 2-Mbit and 8-Mbit
pinouts going outward from the center.
PRELIMINARY
7
INTEL [ INTEL CORPORATION ]
