TA235 ST Microelectronics, Inc., TA235 Datasheet - Page 4

• Manufacturer Part Number: TA235
• Description: Technical Article
• Manufacturer: ST Microelectronics, Inc.

TA 235
The A/A Mux Interface bus operation is similar to
a standard flash programming protocol with the
exception that addressing is latched using the
Row/Column Select inputs. The lower address
signals (A0–A10) determine the Row Address bits
and the higher address signals (A11-A18)
determine the Column Address bits. Figure 5
shows the Address/Address Multiplexed Interface
Read Protocol, and Figure 6 the Address/Address
Multiplexed Interface Write Protocol.
Firmware Security
Intel plans to add new security and software
functions to their chip-sets in a move that will boost
the profile of its future processors for the
multimedia and electronic markets. These are the
key features of the FWH that is basically a flash
with locks on its read and write capabilities that
can be opened using a cryptographic protocol.
The hardware security functions include a
cryptographic engine to authenticate ‘digital
certificates’ which Intel or a third party could load
4/6
Figure 6. Address/Address Multiplexed Interface Write Protocol
A0-A10
RC
W
G
RB
V PP
DQ0-DQ7
RP
tWLWH
Write erase or
program setup
R1
tAVCL
tWHWL
tPHWL
tCLAX
C1
D IN1
valid address and data
Write erase confirm or
tAVCH
R2
tVPHWH
tDVWH
tCHAX
tWHRL
C2
D IN2
tWLCH
tCHWH
in. The FWH could hold multiple certificates, each
able to grant specific features and ensure a
software program licensed to one user could not
be copied and run on another machine. In
addition, the certificates will act as unique serial
numbers, identifying a given machine in any
Internet or corporate network transaction.
Appendix 1
The Firmware Hub comes in two standard
packages of 32 pins PLCC (as shown in Figure 7)
and 40 pins TSOP (as shown in Figure 8).
References
1. Intel’s security plans raise fear from PC build-
Automated erase
or program delay
ers, Rick Boyd-Merritt & Mark Carroll, EDTN
News, 15 Dec 1998.
tWHDX
tWHGL
Register Data
Read Status
VALID SRD
tQVVPL
another command
Ready to write
AI03411